ORCID Profile
0000-0002-5081-5684
Current Organisation
University of Adelaide
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Nanotechnology | Functional Materials | Nanofabrication, Growth and Self Assembly | Nanomanufacturing | Nanomaterials | Materials Engineering | Energy Generation, Conversion and Storage Engineering | Environmental Technologies | Structural Chemistry and Spectroscopy | Medical Biotechnology Diagnostics (incl. Biosensors) | Nanometrology | Nanophotonics |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Expanding Knowledge in Technology | Renewable Energy not elsewhere classified | Cardiovascular System and Diseases | Expanding Knowledge in the Chemical Sciences | Manufacturing not elsewhere classified
Related Links
Publications
Advanced biopolymer-coated drug-releasing titania nanotubes (TNTs) implants with simultaneously enhanced osteoblast adhesion and antibacterial properties
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.COLSURFB.2015.04.021
Abstract: Here, we report on the development of advanced biopolymer-coated drug-releasing implants based on titanium (Ti) featuring titania nanotubes (TNTs) on its surface. These TNT arrays were fabricated on the Ti surface by electrochemical anodization, followed by the loading and release of a model antibiotic drug, gentamicin. The osteoblastic adhesion and antibacterial properties of these TNT-Ti s les are significantly improved by loading antibacterial payloads inside the nanotubes and modifying their surface with two biopolymer coatings (PLGA and chitosan). The improved osteoblast adhesion and antibacterial properties of these drug-releasing TNT-Ti s les are confirmed by the adhesion and proliferation studies of osteoblasts and model Gram-positive bacteria (Staphylococcus epidermidis). The adhesion of these cells on TNT-Ti s les is monitored by fluorescence and scanning electron microscopies. Results reveal the ability of these biopolymer-coated drug-releasing TNT-Ti substrates to promote osteoblast adhesion and proliferation, while effectively preventing bacterial colonization by impeding their proliferation and biofilm formation. The proposed approach could overcome inherent problems associated with bacterial infections on Ti-based implants, simultaneously enabling the development of orthopedic implants with enhanced and synergistic antibacterial functionalities and bone cell promotion.
Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR01068G
Abstract: Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information.
Modulation of Macrophages Differentiation by Nanoscale-Engineered Geometric and Chemical Features.
Publisher: American Chemical Society (ACS)
Date: 16-02-2020
Abstract: Macrophage differentiation into M1 (inflammatory) and M2 (healing) phenotypes plays a vital role in determining the fate of biomaterials. The biophysical properties of the extracellular matrix are known to affect macrophage behavior. Mimicking these special biophysical properties of the extracellular matrix has led to increasing interest in biomaterial constructs with tailor-engineered surface nanotopographical and chemical properties. However, a significant gap of knowledge exists in the role played by the combinational effect of surface nanotopography and chemistry. To address this gap, we have fabricated nanoporous surfaces of controlled pore size (30, 65, and 200 nm) and lateral spacing with uniform outermost surface chemistry tailored with amines (NH
Assessment of Binding Affinity between Drugs and Human Serum Albumin Using Nanoporous Anodic Alumina Photonic Crystals
Publisher: American Chemical Society (ACS)
Date: 10-05-2016
DOI: 10.1021/ACS.ANALCHEM.6B00993
Abstract: In this study, we report an innovative approach aiming to assess the binding affinity between drug molecules and human serum albumin by combining nanoporous anodic alumina rugate filters (NAA-RFs) modified with human serum albumin (HSA) and reflectometric interference spectroscopy (RIfS). NAA-RFs are photonic crystal structures produced by sinusoidal pulse anodization of aluminum that present two characteristic optical parameters, the characteristic reflection peak (λPeak), and the effective optical thickness of the film (OTeff), which can be readily used as sensing parameters. A design of experiments strategy and an ANOVA analysis are used to establish the effect of the anodization parameters (i.e., anodization period and anodization offset) on the sensitivity of HSA-modified NAA-RFs toward indomethacin, a model drug. To this end, two sensing parameters are used, that is, shifts in the characteristic reflection peak (ΔλPeak) and changes in the effective optical thickness of the film (ΔOTeff). Subsequently, optimized NAA-RFs are used as sensing platforms to determine the binding affinity between a set of drugs (i.e., indomethacin, coumarin, sulfadymethoxine, warfarin, and salicylic acid) and HSA molecules. Our results verify that the combination of HSA-modified NAA-RFs with RIfS can be used as a portable, low-cost, and simple system for establishing the binding affinity between drugs and plasma proteins, which is a critical factor to develop efficient medicines for treating a broad range of diseases and medical conditions.
On The Generation of Interferometric Colors in High Purity and Technical Grade Aluminum: An Alternative Green Process for Metal Finishing Industry
Publisher: Elsevier BV
Date: 08-2015
Rational Design of Ultra-Short Anodic Alumina Nanotubes by Short-Time Pulse Anodization
Publisher: Elsevier BV
Date: 02-2015
Hierarchical nanoporous anodic alumina templates by asymmetric two-step anodization
Publisher: Wiley
Date: 07-12-2011
Nanoporous Anodic Alumina Photonic Crystals for Sunlight Harvesting Applications: A Perspective
Publisher: Wiley
Date: 09-08-2022
Abstract: Nanoporous anodic alumina (NAA) fabricated by anodization of aluminum is a versatile platform material with tailorable geometric, optical, and chemical features for specific light‐based technologies and applications. Recent advances in anodization technology have enabled a new generation of NAA‐based photonic crystals (PCs)—periodic dielectric nanoporous structures that selectively allow, forbid, and confine the flow of incoming electromagnetic waves of specific wavelengths across their structure. NAA–PCs provide exciting new opportunities to engineer light–matter interactions with versatility across the broad spectrum, from UV to IR. But despite these fundamental advances, demonstrations of sunlight‐harvesting technologies based on NAA–PCs are still limited. Herein, an up‐to‐date summary of recent advances in NAA–PC technology is provided, and proof‐of‐concept demonstrations and future pathways to propel this versatile platform material across sunlight‐harvesting technologies such as photocatalysis, photoelectrocatalysis, photothermal energy conversion, and solar cells are discussed.
Structural tailoring of nanoporous anodic alumina optical microcavities for enhanced resonant recirculation of light
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR04263B
Abstract: A study about the structural engineering of high quality nanoporous anodic alumina optical microcavities (NAA-μCVs) fabricated by rationally designed anodisation strategies to enhance the light-confining capabilities of these photonic crystal (PC) structures is presented.
Role of Spectral Resonance Features and Surface Chemistry in the Optical Sensitivity of Light-Confining Nanoporous Photonic Crystals
Publisher: American Chemical Society (ACS)
Date: 18-03-2021
Nanoporous Anodic Alumina Photonic Crystals for Sunlight Harvesting Applications: A Perspective
Publisher: Wiley
Date: 10-2022
Generation of Tamm Plasmon Resonances for Light Confinement Applications in Narrowband Gradient-Index Filters Based on Nanoporous Anodic Alumina
Publisher: American Chemical Society (ACS)
Date: 22-03-2023
The influence of rest break frequency and duration on physical performance and psychophysiological responses: a mining simulation study
Publisher: Springer Science and Business Media LLC
Date: 21-06-2022
DOI: 10.1007/S00421-022-04979-3
Abstract: To investigate the influence of shorter, more frequent rest breaks during simulated work (outdoor mining) in the heat on physical performance and psychophysiological responses. On separate days, thirteen males undertook two 225 min simulation trials in the afternoon (12.00–3.45 pm) including 180 min of treadmill walking at a constant rate of perceived exertion of 11 (or ‘light’) on the 6–20 Borg scale in a heat chamber (37 °C, 40% RH), interspersed with 45 min of rest breaks in an air-conditioned room (22 °C, 35% RH). Rest breaks in the current practice (CP) trial occurred at 1.00 and 2.30 pm (30 min and 15 min, respectively), while in the experimental (EXP) trial were at 1.00 (15 min), 1.45, 2.25 and 3.05 pm (10 min each). Total distance covered was not different ( p = 0.086) between CP (12,858 ± 2207 m) and EXP (12,094 ± 2174 m). Heart rate, thermal sensation and thermal comfort were significantly higher at 120–180 min (all p 0.05) in CP compared to EXP. Moderate- to large-effect sizes (Hedge’s g) between trials were also found at 120–180 min for core temperature ( g = 0.50 and 0.99, respectively). No differences were found between trials for cognitive performance, perceived fatigue, urine specific gravity, or total water intake ( p 0.05). Shorter, more frequent rest breaks have little impact on physical performance, thermal strain and exercise-related sensations. Current practices should remain in place until further studies can be conducted on an actual mine site during summer where outdoor workers perform their work duties.
Structural Engineering of the Barrier Oxide Layer of Nanoporous Anodic Alumina for Iontronic Sensing
Publisher: American Chemical Society (ACS)
Date: 29-04-2022
Abstract: The hemispherical barrier oxide layer (BOL) closing the bottom tips of hexagonally distributed arrays of cylindrical nanochannels in nanoporous anodic alumina (NAA) membranes is structurally engineered by anodizing aluminum substrates in three distinct acid electrolytes at their corresponding self-ordering anodizing potentials. These nanochannels display a characteristic ionic current rectification (ICR) signal between high and low ionic conduction states, which is determined by the thickness and chemical composition of the BOL and the pH of the ionic electrolyte solution. The rectification efficiency of the ionic current associated with the flow of ions across the anodic BOL increases with its thickness, under optimal pH conditions. The inner surface of the nanopores in NAA membranes was chemically modified with thiol-terminated functional molecules. The resultant NAA-based iontronic system provides a model platform to selectively detect gold metal ions (Au
Carbon Nanotubes-Nanoporous Anodic Alumina Composite Membranes: Influence of Template on Structural, Chemical, and Transport Properties
Publisher: American Chemical Society (ACS)
Date: 19-06-2017
Interferometric nanoporous anodic alumina photonic coatings for optical sensing
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR00369E
Abstract: Herein, we present a systematic study on the development, optical optimization and sensing applicability of colored photonic coatings based on nanoporous anodic alumina films grown on aluminum substrates. These optical nanostructures, so-called distributed Bragg reflectors (NAA-DBRs), are fabricated by galvanostatic pulse anodization process, in which the current density is altered in a periodic manner in order to engineer the effective medium of the resulting photonic coatings. As-prepared NAA-DBR photonic coatings present brilliant interference colors on the surface of aluminum, which can be tuned at will within the UV-visible spectrum by means of the anodization profile. A broad library of NAA-DBR colors is produced by means of different anodization profiles. Then, the effective medium of these NAA-DBR photonic coatings is systematically assessed in terms of optical sensitivity, low limit of detection and linearity by reflectometric interference spectroscopy (RIfS) in order to optimize their nanoporous structure toward optical sensors with enhanced sensing performance. Finally, we demonstrate the applicability of these photonic nanostructures as optical platforms by selectively detecting gold(iii) ions in aqueous solutions. The obtained results reveal that optimized NAA-DBR photonic coatings can achieve an outstanding sensing performance for gold(iii) ions, with a sensitivity of 22.16 nm μM(-1), a low limit of detection of 0.156 μM (i.e. 30.7 ppb) and excellent linearity within the working range (0.9983).
Fine tuning of optical signals in nanoporous anodic alumina photonic crystals by apodized sinusoidal pulse anodisation
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR06796D
Abstract: In this study, we present an advanced nanofabrication approach to produce gradient-index photonic crystal structures based on nanoporous anodic alumina. An apodization strategy is for the first time applied to a sinusoidal pulse anodisation process in order to engineer the photonic stop band of nanoporous anodic alumina (NAA) in depth. Four apodization functions are explored, including linear positive, linear negative, logarithmic positive and logarithmic negative, with the aim of finely tuning the characteristic photonic stop band of these photonic crystal structures. We systematically analyse the effect of the litude difference (from 0.105 to 0.840 mA cm
Biomimetic Nanoporous Anodic Alumina Distributed Bragg Reflectors in the Form of Films and Microsized Particles for Sensing Applications
Publisher: American Chemical Society (ACS)
Date: 26-08-2015
Abstract: In this study, we produce for the first time biomimetic films and microsized particles based on nanoporous anodic alumina distributed Bragg reflectors (NAA-DBRs) by a rational galvanostatic pulse-anodization approach. These biomimetic photonic structures can feature a broad range of vivid bright colors, which can be tuned across the UV-visible spectrum by engineering their nanoporous structure through different anodization parameters. The effective medium of NAA-DBRs films is systematically assessed as a function of the anodization period, the anodization temperature, and the current density ratio by reflectometric interference spectroscopy (RIfS). This analysis makes it possible to establish the most sensitive structure toward changes in its effective medium. Subsequently, specific detection of vitamin C molecules is demonstrated. The obtained results reveal that NAA-DBRs with optimized structure can achieve a low limit of detection for vitamin C molecules as low as 20 nM, a sensitivity of 227±4 nm μM(-1), and a linearity of 0.9985. Finally, as proof of concept, we developed a new photonic nanomaterial based on NAA-DBR microsized particles, which could provide new opportunities to produce microsized photonic analytical tools.
Luminescent Silicon Diatom Replicas: Self-Reporting and Degradable Drug Carriers with Biologically Derived Shape for Sustained Delivery of Therapeutics
Publisher: Wiley
Date: 14-07-2015
Optically optimized photoluminescent and interferometric biosensors based on nanoporous anodic alumina: A comparison
Publisher: American Chemical Society (ACS)
Date: 02-08-2013
DOI: 10.1021/AC401609C
Abstract: Herein, we present a comparative study about the sensing performance of optical biosensors based on photoluminescence spectroscopy (PLS) and reflectometric interference spectroscopy (RIfS) combined with nanoporous anodic alumina (NAA) platforms when detecting different analytes under distinct adsorption conditions. First, NAA platforms are structurally engineered in order for optimizing the optical signals obtained by PLS and RIfS. Then, the most optimal NAA platforms combined with PLS and RIfS are quantitatively compared by detecting two different analytes: d-glucose and l-cysteine under nonspecific and specific adsorption conditions, respectively. The obtained results demonstrate that such parameters as the analyte nature and adsorption conditions play a direct role in the sensing performance of these platforms. However, as this study demonstrates, PLS-NAA platforms are more sensitive than RIfS-NAA ones. The former shows better linearity (i.e., proportional change in the sensing parameter with analyte concentration), higher sensitivity toward analytes (i.e., sharper change in the sensing parameter with analyte concentration), and lower limit of detection (i.e., minimum detectable concentration of analyte).
Harnessing Slow Light in Optoelectronically Engineered Nanoporous Photonic Crystals for Visible Light-Enhanced Photocatalysis
Publisher: American Chemical Society (ACS)
Date: 11-10-2021
Real-Time Binding Monitoring between Human Blood Proteins and Heavy Metal Ions in Nanoporous Anodic Alumina Photonic Crystals
Publisher: American Chemical Society (ACS)
Date: 25-07-2018
DOI: 10.1021/ACS.ANALCHEM.8B02732
Abstract: This study reports on the real-time binding assessment between heavy metal ions and blood proteins immobilized onto nanoporous anodic alumina photonic crystals (NAA-PCs) by reflectometric interference spectroscopy (RIfS). The surface of NAA-PCs is chemically functionalized with γ-globulin (GG), transferrin (TFN), and serum albumin (HSA), the major proteins present in human blood plasma. Protein-modified NAA-PC platforms are exposed to analytical solutions of mercury ions of different concentrations. Dynamic changes in the effective optical thickness of protein-modified NAA-PCs in response to heavy metal ions are assessed in real time to evaluate the binding kinetics, affinity, and mechanism. Protein molecules undergo conformational changes upon exposure to mercury ions, with HSA exhibiting the strongest affinity. The combination of protein-modified NAA-PCs with RIfS allows real-time monitoring of protein-heavy metal ions interactions under dynamic flow conditions. This system is capable of detecting dynamic conformational changes in these proteins upon exposure to heavy metal ions. Our results provide new insights into these binding events, which could enable new methodologies to study the toxicity of heavy metal ions and other biomolecular interactions.
Light-confining semiconductor nanoporous anodic alumina optical microcavities for photocatalysis
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TA08585H
Abstract: An extensive study on the structural engineering of titanium dioxide-functionalized nanoporous anodic alumina optical microcavities (TiO 2 -NAA-μQVs) for photocatalysis enhanced by light confinement is presented.
From The Mine to Cancer Therapy: Natural and Biodegradable Theranostic Silicon Nanocarriers from Diatoms for Sustained Delivery of Chemotherapeutics
Publisher: Wiley
Date: 05-09-2016
Realisation and advanced engineering of true optical rugate filters based on nanoporous anodic alumina by sinusoidal pulse anodisation
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5NR05462A
Abstract: This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic mode is used with the aim of engineering the effective medium of NAA in a sinusoidal fashion. A precise control over the different anodisation parameters (i.e. anodisation period, anodisation litude, anodisation offset, number of pulses, anodisation temperature and pore widening time) makes it possible to engineer the characteristic reflection peaks and interferometric colours of NAA-RFs, which can be finely tuned across the UV-visible-NIR spectrum. The effect of the aforementioned anodisation parameters on the photonic properties of NAA-RFs (i.e. characteristic reflection peaks and interferometric colours) is systematically assessed in order to establish for the first time a comprehensive rationale towards NAA-RFs with fully controllable photonic properties. The experimental results are correlated with a theoretical model (Looyenga-Landau-Lifshitz - LLL), demonstrating that the effective medium of these photonic nanostructures can be precisely described by the effective medium approximation. NAA-RFs are also demonstrated as chemically selective photonic platforms combined with reflectometric interference spectroscopy (RIfS). The resulting optical sensing system is used to assess the reversible binding affinity between a model drug (i.e. indomethacin) and human serum albumin (HSA) in real-time. Our results demonstrate that this system can be used to determine the overall pharmacokinetic profile of drugs, which is a critical aspect to be considered for the implementation of efficient medical therapies.
Enhanced Visible Light Photocatalysis in Titanium Dioxide-Functionalized Nanoporous Anodic Alumina Photonic Crystals
Publisher: OSA
Date: 2018
Rational Design of Photonic Dust from Nanoporous Anodic Alumina Films: A Versatile Photonic Nanotool for Visual Sensing
Publisher: Springer Science and Business Media LLC
Date: 06-08-2015
DOI: 10.1038/SREP12893
Abstract: Herein, we present a systematic study on the development, optimisation and applicability of interferometrically coloured distributed Bragg reflectors based on nanoporous anodic alumina (NAA-DBRs) in the form of films and nanoporous microparticles as visual/colorimetric analytical tools. Firstly, we synthesise a complete palette of NAA-DBRs by galvanostatic pulse anodisation approach, in which the current density is altered in a periodic fashion in order to engineer the effective medium of the resulting photonic films in depth. NAA-DBR photonic films feature vivid colours that can be tuned across the UV-visible-NIR spectrum by structural engineering. Secondly, the effective medium of the resulting photonic films is assessed systematically by visual analysis and reflectometric interference spectroscopy (RIfS) in order to establish the most optimal nanoporous platforms to develop visual/colorimetric tools. Then, we demonstrate the applicability of NAA-DBR photonic films as a chemically selective sensing platform for visual detection of mercury(II) ions. Finally, we generate a new nanomaterial, so-called photonic dust, by breaking down NAA-DBRs films into nanoporous microparticles. The resulting microparticles (μP-NAA-DBRs) display vivid colours and are sensitive towards changes in their effective medium, opening new opportunities for developing advanced photonic nanotools for a broad range of applications.
Tunable Nanoporous Anodic Alumina Photonic Crystals by Gaussian Pulse Anodization
Publisher: American Chemical Society (ACS)
Date: 31-03-0005
Generation of guided pores in nanoporous anodic alumina by nanoimprinting
Publisher: IEEE
Date: 02-2011
Nanoporous Anodic Alumina Rugate Filters for Sensing of Ionic Mercury: Toward Environmental Point-of-Analysis Systems
Publisher: American Chemical Society (ACS)
Date: 24-07-2014
DOI: 10.1021/AM502882D
Abstract: Herein, we present an ultrasensitive, cost-competitive, and portable optical sensing system for detecting ionic mercury in environmental water. This analytical system combines structurally engineered and chemically modified nanoporous anodic alumina rugate filters (NAA-RFs) with reflection spectroscopy (RfS). The sensing performance of the proposed system is assessed through several tests, establishing its sensing performance (i.e., linear working range from 1 to 100 μM of Hg(2+), low limit of detection 1 μM of Hg(2+) ions (i.e., 200 ppb), and sensitivity of 0.072 nm μM(-1)), chemical selectivity (i.e., exposure to different metal ions Co(2+), Mg(2+), Ni(2+), Cu(2+), Pb(2+), Fe(3+), Ca(2+), Cr(6+), and Ag(+)) and metal ions binding mechanism (i.e., fitting to Langmuir and Freundlich isotherm models). Furthermore, the detection of Hg(2+) ions in tap and environmental water (River Torrens) is successfully carried out, demonstrating the suitability of this system for developing environmental point-of-analysis systems.
Nanoporous anodic alumina barcodes: Toward smart optical biosensors
Publisher: Wiley
Date: 20-01-2012
Abstract: Toward a smart optical biosensor based on nanoporous anodic alumina (NAA): by modifying the pore geometry in nanoporous anodic alumina we are able to change the effective medium at will and tune the photoluminescence of NAA. The oscillations in the PL spectrum are converted into exclusive barcodes, which are useful for developing optical biomedical sensors in the UV-Visible region.
On the Precise Tuning of Optical Filtering Features in Nanoporous Anodic Alumina Distributed Bragg Reflectors
Publisher: Springer Science and Business Media LLC
Date: 15-03-2018
DOI: 10.1038/S41598-018-22895-5
Abstract: This study presents a nanofabrication approach that enables the production of nanoporous anodic alumina distributed Bragg reflectors (NAA-DBRs) with finely engineered light filtering features across the spectral regions. The photonic stopband (PSB) of these NAA-based photonic crystal (PC) structures is precisely tuned by an apodization strategy applied during stepwise pulse anodization with the aim of engineering the effective medium of NAA-DBRs in depth. We systematically assess the effect of different fabrication parameters such as apodization function (i.e. linear positive, linear negative, logarithmic positive and logarithmic negative), litude difference (from 0.105 to 0.420 mA cm −2 ), current density offset (from 0.140 to 0.560 mA cm −2 ), anodization period (from 1100 to 1700 s), and pore widening time (from 0 to 6 min) on the quality and central wavelength of the PSB of NAA-DBRs. The PSB’s features these PC structures are demonstrated to be highly tunable with the fabrication parameters, where a logarithmic negative apodization is found to be the most effective function to produce NAA-DBRs with high quality PSBs across the UV-visible-NIR spectrum. Our study establishes that apodized NAA-DBRs are more sensitive to changes in their effective medium than non-apodized NAA-DBRs, making them more suitable sensing platforms to develop advanced optical sensing systems.
Spectral Engineering of Tamm Plasmon Resonances in Dielectric Nanoporous Photonic Crystal Sensors
Publisher: American Chemical Society (ACS)
Date: 19-10-2021
Structural engineering of nanoporous anodic alumina funnels with high aspect ratio
Publisher: Elsevier BV
Date: 05-2011
Nanoporous anodic alumina-based iontronics: fundamentals and applications
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3TC01735D
Abstract: An overview of structural, chemical, and iontronic properties of nanoporous anodic alumina (NAA) with proof-of-principle demonstrations of state-of-the-art iontronic applications such as ionic diodes, sensors, and osmotic energy generators.
Structural Engineering of Nanoporous Anodic Alumina Photonic Crystals by Sawtooth-like Pulse Anodization
Publisher: American Chemical Society (ACS)
Date: 20-05-2016
Abstract: This study presents a sawtooth-like pulse anodization approach aiming to create a new type of photonic crystal structure based on nanoporous anodic alumina. This nanofabrication approach enables the engineering of the effective medium of nanoporous anodic alumina in a sawtooth-like manner with precision. The manipulation of various anodization parameters such as anodization period, anodization litude, number of anodization pulses, r ratio and pore widening time allows a precise control and fine-tuning of the optical properties (i.e., characteristic transmission peaks and interferometric colors) exhibited by nanoporous anodic alumina photonic crystals (NAA-PCs). The effect of these anodization parameters on the photonic properties of NAA-PCs is systematically evaluated for the establishment of a fabrication methodology toward NAA-PCs with tunable optical properties. The effective medium of the resulting NAA-PCs is demonstrated to be optimal for the development of optical sensing platforms in combination with reflectometric interference spectroscopy (RIfS). This application is demonstrated by monitoring in real-time the formation of monolayers of thiol molecules (11-mercaptoundecanoic acid) on the surface of gold-coated NAA-PCs. The obtained results reveal that the adsorption mechanism between thiol molecules and gold-coated NAA-PCs follows a Langmuir isotherm model, indicating a monolayer sorption mechanism.
Facile and controllable route for nitrogen doping of carbon nanotubes composite membranes by catalyst-free chemical vapour deposition
Publisher: Elsevier BV
Date: 09-2016
Optofluidic characterization of nanoporous membranes
Publisher: American Chemical Society (ACS)
Date: 13-02-2013
DOI: 10.1021/LA304869Y
Abstract: An optofluidic method that accurately identifies the internal geometry of nanochannel arrays is presented. It is based on the dynamics of capillary-driven fluid imbibition, which is followed by laser interferometry. Conical nanochannel arrays in anodized alumina are investigated, which present an asymmetry of the filling times measured from different sides of the membrane. It is demonstrated by theory and experiments that the capillary filling asymmetry only depends on the ratio H of the inlet to outlet pore radii and that the ratio of filling times vary closely as H(7/3). Besides, the capillary filling of conical channels exhibits striking results in comparison to the corresponding cylindrical channels. Apart from these novel results in nanoscale fluid dynamics, the whole method discussed here serves as a characterization technique for nanoporous membranes.
Template‐assisted fabrication and characterization of photoluminescent polymer nanopillars
Publisher: Wiley
Date: 27-05-2011
Carbon nanotube-nanoporous anodic alumina composite membranes with controllable inner diameters and surface chemistry: Influence on molecular transport and chemical selectivity
Publisher: Elsevier BV
Date: 11-2015
Understanding and morphology control of pore modulations in nanoporous anodic alumina by discontinuous anodization
Publisher: Wiley
Date: 26-06-2012
Nanoengineered drug-releasing aluminium wire implants: comparative investigation of nanopore geometry, drug release and osteoblast cell adhesion
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA10418A
Abstract: In this study, drug-releasing aluminium (Al) wire implants featuring nanoporous alumina (NPA) layers produced by different anodization approaches are systematically investigated as potential platforms for localized drug delivery and bone therapy.
Titania nanotube arrays for local drug delivery: Recent advances and perspectives
Publisher: Informa Healthcare
Date: 07-11-2015
DOI: 10.1517/17425247.2014.945418
Abstract: Titania nanotube (TNTs) arrays engineered by simple and scalable electrochemical anodization process have been extensively explored as a new nanoengineering approach to address the limitations of systemic drug administration. Due to their outstanding properties and excellent biocompatibility, TNTs arrays have been used to develop new drug-releasing implants (DRI) for emerging therapies based on localized drug delivery (DD). This review highlights the concepts of DRI based on TNTs with a focus on recent progress in their development and future perspectives towards advanced medical therapies. Recent progress in new strategies for controlling drug release from TNTs arrays aimed at designing TNTs-based DRI with optimized performances, including extended drug release and zero-order release kinetics and remotely activated release are described. Furthermore, significant progress in biocompatibility studies on TNTs and their outstanding properties to promote hydroxyapatite and bone cells growths and to differentiate stem cells are highlighted. Ex les of ex vivo and in vivo studies of drug-loaded TNTs are shown to confirm the practical and potential applicability of TNTs-based DRI for clinical studies. Finally, selected ex les of preliminary clinical applications of TNTs for bone therapy and orthopedic implants, cardiovascular stents, dentistry and cancer therapy are presented. As current studies have demonstrated, TNTs are a remarkable material that could potentially revolutionize localized DD therapies, especially in areas of orthopedics and localized chemotherapy. However, more extensive ex vivo and in vivo studies should be carried out before TNTs-based DRI could become a feasible technology for real-life clinical applications. This will imply the implementation of different approaches to overcome some technical and commercial challenges.
Nanoporous anodic alumina platforms: Engineered surface chemistry and structure for optical sensing applications
Publisher: MDPI AG
Date: 07-07-2014
DOI: 10.3390/S140711878
Quasi-ordered P3HT nanopillar-nanocap structures with controlled size
Publisher: Elsevier BV
Date: 02-2010
In situ electrochemical dissolution of the oxide barrier layer of porous anodic alumina fabricated by hard anodization
Publisher: Elsevier BV
Date: 07-2009
Nanoporous Anodic Alumina Photonic Crystals for Optical Chemo- and Biosensing: Fundamentals, Advances, and Perspectives
Publisher: MDPI AG
Date: 04-10-2018
DOI: 10.3390/NANO8100788
Abstract: Optical sensors are a class of devices that enable the identification and/or quantification of analyte molecules across multiple fields and disciplines such as environmental protection, medical diagnosis, security, food technology, biotechnology, and animal welfare. Nanoporous photonic crystal (PC) structures provide excellent platforms to develop such systems for a plethora of applications since these engineered materials enable precise and versatile control of light–matter interactions at the nanoscale. Nanoporous PCs provide both high sensitivity to monitor in real-time molecular binding events and a nanoporous matrix for selective immobilization of molecules of interest over increased surface areas. Nanoporous anodic alumina (NAA), a nanomaterial long envisaged as a PC, is an outstanding platform material to develop optical sensing systems in combination with multiple photonic technologies. Nanoporous anodic alumina photonic crystals (NAA-PCs) provide a versatile nanoporous structure that can be engineered in a multidimensional fashion to create unique PC sensing platforms such as Fabry–Pérot interferometers, distributed Bragg reflectors, gradient-index filters, optical microcavities, and others. The effective medium of NAA-PCs undergoes changes upon interactions with analyte molecules. These changes modify the NAA-PCs’ spectral fingerprints, which can be readily quantified to develop different sensing systems. This review introduces the fundamental development of NAA-PCs, compiling the most significant advances in the use of these optical materials for chemo- and biosensing applications, with a final prospective outlook about this exciting and dynamic field.
On the mechanical properties of nanoporous anodized alumina by nanoindentation and sliding tests
Publisher: Elsevier BV
Date: 2012
Nanoporous anodic alumina obtained without protective oxide layer by hard anodization
Publisher: Elsevier BV
Date: 2012
Highly biocompatible carbon nanocapsules derived from plastic waste for advanced cancer therapy
Publisher: Elsevier BV
Date: 10-2017
Structurally engineered anodic alumina nanotubes as nano-carriers for delivery of anticancer therapeutics
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.BIOMATERIALS.2014.03.059
Abstract: Here, we report a study on the biocompatibility, cell uptake and in vitro delivery of tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) by new nano-carriers called anodic alumina nanotubes (AANTs) for potential cancer therapy. AANTs were electrochemically engineered by a unique pulse anodization process, which enables precise control of the nanotube geometry, and used here as nano-carriers for drug delivery. In vitro cytotoxicity and cell uptake of AANTs was assessed using MDA-MB231-TXSA human breast cancer cells and mouse RAW 264.7 macrophage cells. AANTs exhibited excellent biocompatibility in both cell lines over a time course of five days even at a maximum concentration of AANTs of 100 μgmL(-1). Transmission electron microscopy and fluorescence microscopy confirmed a significant uptake of AANTs by RAW 264.7 cells and breast cancer cells. AANTs loaded with the pro-apoptotic protein Apo2L/TRAIL showed exceptional loading capacity (104 ± 14.4 μgmg(-1) of AANTs) and demonstrated significant decrease in viability of MDA-MB231-TXSA cancer cells due to apoptosis induction. These results demonstrate that AANTs are promising nano-carriers for drug delivery applications.
Cobalt and nickel nanopillars on aluminium substrates by direct current electrodeposition process
Publisher: Springer Science and Business Media LLC
Date: 31-05-2009
DOI: 10.1007/S11671-009-9351-5
Abstract: A fast and cost-effective technique is applied for fabricating cobalt and nickel nanopillars on aluminium substrates. By applying an electrochemical process, the aluminium oxide barrier layer is removed from the pore bottom tips of nanoporous anodic alumina templates. So, cobalt and nickel nanopillars are fabricated into these templates by DC electrodeposition. The resulting nanostructure remains on the aluminium substrate. In this way, this method could be used to fabricate a wide range of nanostructures which could be integrated in new nanodevices.
Electrochemical engineering of nanoporous materials
Publisher: MDPI AG
Date: 06-09-2018
DOI: 10.3390/NANO8090691
Abstract: n/a
Modulating molecular transport across peptide-modified nanoporous alumina membranes with light
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2241495
Surface modification of nanoporous anodic alumina photonic crystals for photocatalytic applications
Publisher: SPIE
Date: 02-01-2018
DOI: 10.1117/12.2282248
Engineering of Solid-State Random Lasing in Nanoporous Anodic Alumina Photonic Crystals
Publisher: American Chemical Society (ACS)
Date: 10-08-2022
In vivo toxicological assessment of electrochemically engineered anodic alumina nanotubes: a study of biodistribution, subcutaneous implantation and intravenous injection
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TB00222J
Abstract: First pilot toxicity study on anodic alumina nanotubes in immune-competent murine models.
Stacked Nanoporous Anodic Alumina Gradient-Index Filters with Tunable Multispectral Photonic Stopbands as Sensing Platforms
Publisher: American Chemical Society (ACS)
Date: 27-12-2018
Abstract: This study presents the development and optical engineering of stacked nanoporous anodic alumina gradient-index (NAA-GIFs) filters with tunable multispectral photonic stopbands for sensing applications. The structure of these photonic crystals (PC) is formed by stacked layers of NAA produced with sinusoidally modified effective medium. The progressive modification of the sinusoidal period during the anodization process enables the generation and precise tuning of the characteristic photonic stopbands (PSB) (i.e., one per sinusoidal period in the anodization profile) of these PC structures. Four types of NAA-GIFs featuring three distinctive PSBs positioned within the visible spectral region are developed. The sensitivity of the effective medium of these NAA-GIFs is systematically assessed by measuring spectral shifts in the characteristic PSBs upon infiltration of their nanoporous structure with analytical solutions of d-glucose with several concentrations (0.025-1 M). This study provides new insights into the intrinsic relationship between the nanoporous architecture of these PCs and their optical properties, generating opportunities to fabricate advanced optical sensing systems for high-throughput and multiplexed detection of analytes in a single sensing platform.
Engineering of Surface Chemistry for Enhanced Sensitivity in Nanoporous Interferometric Sensing Platforms
Publisher: American Chemical Society (ACS)
Date: 06-03-2017
Abstract: We explore new approaches to engineering the surface chemistry of interferometric sensing platforms based on nanoporous anodic alumina (NAA) and reflectometric interference spectroscopy (RIfS). Two surface engineering strategies are presented, namely (i) selective chemical functionalization of the inner surface of NAA pores with amine-terminated thiol molecules and (ii) selective chemical functionalization of the top surface of NAA with dithiol molecules. The strong molecular interaction of Au
Bioinert Anodic Alumina Nanotubes for Targeting of Endoplasmic Reticulum Stress and Autophagic Signaling: A Combinatorial Nanotube-Based Drug Delivery System for Enhancing Cancer Therapy
Publisher: American Chemical Society (ACS)
Date: 12-2015
Abstract: Although nanoparticle-based targeted delivery systems have gained promising achievements for cancer therapy, the development of sophisticated strategies with effective combinatorial therapies remains an enduring challenge. Herein, we report the fabrication of a novel nanomaterial, so-called anodic alumina nanotubes (AANTs) for proof-of-concept cancer therapy by targeting cell signaling networks. This strategy is to target autophagic and endoplasmic reticulum (ER) stress signaling by using thapsigargin (TG)-loaded AANTs cotreated with an autophagy inhibitor 3-methyladenine (3-MA). We first show that AANTs are nontoxic and can activate autophagy in different cell types including human fibroblast cells (HFF), human monocyte cells (THP-1), and human breast cancer cells (MDA-MB 231-TXSA). Treatment with 3-MA at a nontoxic dose reduced the level of autophagy induced by AANTs, and consequently sensitized breast cancer cells to AANTs-induced cellular stresses. To target autophagic and ER stress signaling networking, breast cancer cells were treated with 3-MA together with AANTs loaded with the prototype ER stress inducer TG. We demonstrated that 3-MA enhanced the cancer cell killing effect of AANTs loaded with TG. This effect was associated with enhanced ER stress signaling due to the combination effect of TG and 3-MA. These findings not only demonstrate the excellent biocompatibility of AANTs as novel biomaterials but also provide new opportunities for developing ER- and autophagy-targeted delivery systems for future clinical cancer therapy.
Light-Confining Nanoporous Anodic Alumina Microcavities by Apodized Stepwise Pulse Anodization
Publisher: American Chemical Society (ACS)
Date: 28-08-2018
Tuning intrinsic photoluminescence from light-emitting multispectral nanoporous anodic alumina photonic crystals
Publisher: AIP Publishing
Date: 02-2022
DOI: 10.1063/5.0078505
Abstract: To control and harness the intrinsic photoluminescence of solid-state, light-emitting materials produced by self-organization approaches remain challenging. This study demonstrates how the intrinsic broadband photoluminescence emission from nanoporous anodic alumina (NAA) produced by anodization of aluminum in oxalic acid electrolyte can be precisely tuned by engineering its structure in the form of photonic crystals (PCs). A combination of pulse and constant anodization in distinct acid electrolytes makes it possible to engineer a novel heterogeneous optical structure consisting of two layers: (i) a non-emitting, light-filtering layer in the form of multi-spectral nanoporous anodic alumina photonic crystals (MS–NAA–PCs) on its top (i.e., 58 µm thick and average pore diameter of 17 nm) and (ii) an intrinsically light-emitting layer of NAA at its bottom (i.e., 50 µm thick an average pore diameter of 40 nm). MS–NAA–PCs are engineered to feature three intense, well-resolved photonic stopbands (PSBs), the positions of which are spaced at specific regions of the visible spectrum from ∼380 to 560 nm. It is demonstrated that the PSBs of the non-emitting MS–NAA–PCs on top of the heterogeneous optical structure act as a light-filtering component, which makes it possible to narrow and tune the characteristically broad, Gaussian-like photoluminescence emission from the underlying light-emitting NAA layer. This structural design makes it possible to narrow the width of photoluminescence emission up to ∼50 nm and blue shift its position for ∼15 nm. Our advances pave the way for novel designs of intrinsic, light-emitting NAA-based PC structures, which could find broad applicability across light technologies, such as sensing and biosensing, photodetection, and solar light harvesting.
Systematic in vitro nanotoxicity study on anodic alumina nanotubes with engineered aspect ratio: Understanding nanotoxicity by a nanomaterial model
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.BIOMATERIALS.2014.12.008
Abstract: Here, we report a detailed and systematic approach for studying the in vitro nanotoxicity study of high aspect ratio (HAR) nanomaterials using anodic alumina nanotubes (AANTs) as a nanomaterial model. AANTs with bio-inert properties and tailored aspect ratios ranging from 7.8 to 63.3 were synthesized by an electrochemical pulse anodization process. Cytotoxicity studies were conducted with RAW 264.7 mouse macrophage cells and MDA-MB 231-TXSA human breast cancer cells through several toxicity parameters, including cell viability and morphology, pro-inflammatory response, mitochondrial depolarization, lysosomal membrane permeabilization (LMP), induction of autophagy and endoplasmic reticulum (ER) stress. The resulting toxicity patterns were cell-type dependent and strongly related with AANTs dose, length of time, and importantly the AR of AANTs. Long AANTs triggered enhanced cell death, morphological changes, tumor necrosis factor α (TNF-α) release, LMP and ER stress than short AANTs. The toxic AR window of AANTs was determined to be 7.8, which is shorter than that of other previously reported HAR nanomaterials. This toxic AR window provides a promising opportunity to control the nanotoxicity of HAR nanomaterials for their advanced drug delivery application.
Understanding the Intrinsic Rectification Properties of Nanoporous Anodic Alumina by Selective Chemical Etching
Publisher: American Chemical Society (ACS)
Date: 18-09-2023
Fabrication and characterization of high-density arrays of P3HT nanopillars on ITO/glass substrates
Publisher: Elsevier BV
Date: 07-2010
Realisation and optical engineering of linear variable bandpass filters in nanoporous anodic alumina photonic crystals
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR02115A
Abstract: We present the first realisation of linear variable bandpass filters in nanoporous anodic alumina (NAA-LVBPFs) photonic crystal structures. NAA gradient-index filters (NAA-GIFs) are produced by sinusoidal pulse anodisation and used as photonic crystal platforms to generate NAA-LVBPFs. The anodisation period of NAA-GIFs is modified from 650 to 850 s to systematically tune the characteristic photonic stopband of these photonic crystals across the UV-visible-NIR spectrum. Then, the nanoporous structure of NAA-GIFs is gradually widened along the surface under controlled conditions by wet chemical etching using a dip coating approach aiming to create NAA-LVBPFs with finely engineered optical properties. We demonstrate that the characteristic photonic stopband and the iridescent interferometric colour displayed by these photonic crystals can be tuned with precision across the surface of NAA-LVBPFs by adjusting the fabrication and etching conditions. Here, we envisage for the first time the combination of the anodisation period and etching conditions as a cost-competitive, facile, and versatile nanofabrication approach that enables the generation of a broad range of unique LVBPFs covering the spectral regions. These photonic crystal structures open new opportunities for multiple applications, including adaptive optics, hyperspectral imaging, fluorescence diagnostics, spectroscopy, and sensing.
An overview of nanotoxicity and nanomedicine research: principles, progress and implications for cancer therapy
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TB00956A
Abstract: The studies of nanomaterial-based drug delivery and nanotoxicity are closely interconnected.
Nanoporous anodic aluminum oxide for chemical sensing and biosensors
Publisher: Elsevier BV
Date: 03-2013
Engineered therapeutic-releasing nanoporous anodic alumina-aluminum wires with extended release of therapeutics
Publisher: American Chemical Society (ACS)
Date: 06-02-2015
DOI: 10.1021/AM5091963
Abstract: In this study, we present a nanoengineered therapeutic-releasing system based on aluminum wires featuring nanoporous anodic alumina layers and chitosan coatings. Nanoporous anodic alumina layers are produced on the surface of aluminum wires by electrochemical anodization. These nanoporous layers with precisely engineered nanopore geometry are used as nanocontainers for bovine serum albumin molecules labeled with fluorescein isothiocyanate (BSA-FITC), which is selected as a model drug. The surface of these therapeutic-releasing implants is coated with a biocompatible and biodegradable polymer, chitosan, in order to achieve a sustained release of protein over extended periods of time. The performance of this therapeutic-releasing device is systematically assessed through a series of experiments under static and dynamic flow conditions. In these experiments, the effect of such parameters as the number of layers of chitosan coating and the temperature and pH of the eluting medium is established. The obtained results reveal that the proposed therapeutic-releasing system based on nanoporous aluminum wires can be engineered with sustained release performance for up to 6.5 weeks, which is a critical factor for medical treatments using sensitive therapeutics such as proteins and genes when a localized delivery is desired.
Tunable fabry-pérot interferometer based on nanoporous anodic alumina for optical biosensing purposes
Publisher: Springer Science and Business Media LLC
Date: 03-07-2012
Abstract: Here, we present a systematic study about the effect of the pore length and its diameter on the specular reflection in nanoporous anodic alumina. As we demonstrate, the specular reflection can be controlled at will by structural tuning (i.e., by designing the pore geometry). This makes it possible to produce a wide range of Fabry-Pérot interferometers based on nanoporous anodic alumina, which are envisaged for developing smart and accurate optical sensors in such research fields as biotechnology and medicine. Additionally, to systematize the responsiveness to external changes in optical sensors based on nanoporous anodic alumina, we put forward a barcode system based on the oscillations in the specular reflection.
Understanding Pore Rearrangement during Mild to Hard Transition in Bilayered Porous Anodic Alumina Membranes
Publisher: American Chemical Society (ACS)
Date: 23-05-2011
DOI: 10.1021/AM200139K
Abstract: We present a systematic study about the influence of the main anodization parameters (i.e., anodization voltage r and hard anodization voltage) on the pore rearrangement in nanoporous anodic alumina during mild to hard anodization regime transition. To cover the ranges between mild and hard regimes, the anodization parameters were each set to three levels (i.e., 0.5, 1.0, and 2.0 V s(-1) for the anodization voltage r and 80, 110, and 140 V for the hard anodization voltage). To the best of our knowledge, this is the first rigorous study about this phenomenon, which is quantified indirectly by means of a nickel electrodeposition. It is found that pore rearrangement takes place in a relatively random manner. Large areas of pores remain blocked when the anodization regime changes from mild to hard and, under certain anodization conditions, a pore branching takes place based on the self-ordering mechanism at work during anodization. Furthermore, it is statistically demonstrated by means of a design of experiments strategy that the effect of the anodization voltage r on the pore rearrangement is practically negligible in contrast to the hard anodization voltage effect. It is expected that this study gives a better understanding of structural changes in nanoporous anodic alumina when anodization is switched from mild to hard regime. Furthermore, the resulting nanostructures could be used to develop a wide range of nanodevices (e.g., waveguides, 1D photonic crystals, Fabry-Pérot interferometers, hybrid mosaic arrays of nanowires).
Synthesis of ordered polymer micro and nanostructures via porous templates
Publisher: IEEE
Date: 02-2009
Modified hard anodization procedure to fabricate hybrid nanoporous alumina
Publisher: IEEE
Date: 02-2009
Fine tuning of transmission features in nanoporous anodic alumina distributed Bragg reflectors
Publisher: SPIE
Date: 02-01-2018
DOI: 10.1117/12.2282250
Structural and Optical Nanoengineering of Nanoporous Anodic Alumina Rugate Filters for Real-Time and Label-Free Biosensing Applications
Publisher: American Chemical Society (ACS)
Date: 22-01-2014
DOI: 10.1021/AC500069F
Abstract: In this study, we report about the structural engineering and optical optimization of nanoporous anodic alumina rugate filters (NAA-RFs) for real-time and label-free biosensing applications. Structurally engineered NAA-RFs are combined with reflection spectroscopy (RfS) in order to develop a biosensing system based on the position shift of the characteristic peak in the reflection spectrum of NAA-RFs (Δλpeak). This system is optimized and assessed by measuring shifts in the characteristic peak position produced by small changes in the effective medium (i.e., refractive index). To this end, NAA-RFs are filled with different solutions of d-glucose, and the Δλpeak is measured in real time by RfS. These results are validated by a theoretical model (i.e., the Looyenga-Landau-Lifshitz model), demonstrating that the control over the nanoporous structure makes it possible to optimize optical signals in RfS for sensing purposes. The linear range of these optical sensors ranges from 0.01 to 1.00 M, with a low detection limit of 0.01 M of d-glucose (i.e., 1.80 ppm), a sensitivity of 4.93 nm M(-1) (i.e., 164 nm per refractive index units), and a linearity of 0.998. This proof-of-concept study demonstrates that the proposed system combining NAA-RFs with RfS has outstanding capabilities to develop ultrasensitive, portable, and cost-competitive optical sensors.
Lasing from Narrow Bandwidth Light-Emitting One-Dimensional Nanoporous Photonic Crystals
Publisher: American Chemical Society (ACS)
Date: 09-03-2022
Optimizing anodization conditions for the growth of titania nanotubes on curved surfaces
Publisher: American Chemical Society (ACS)
Date: 02-07-2015
Porous silicon for drug delivery applications and theranostics: recent advances, critical review and perspectives
Publisher: Informa UK Limited
Date: 17-04-2017
DOI: 10.1080/17425247.2017.1317245
Abstract: Porous silicon (pSi) engineered by electrochemical etching has been used as a drug delivery vehicle to address the intrinsic limitations of traditional therapeutics. Biodegradability, biocompatibility, and optoelectronic properties make pSi a unique candidate for developing biomaterials for theranostics and photodynamic therapies. This review presents an updated overview about the recent therapeutic systems based on pSi, with a critical analysis on the problems and opportunities that this technology faces as well as highlighting pSi's growing potential. Areas covered: Recent progress in pSi-based research includes drug delivery systems, including biocompatibility studies, drug delivery, theranostics, and clinical trials with the most relevant ex les of pSi-based systems presented here. A critical analysis about the technical advantages and disadvantages of these systems is provided along with an assessment on the challenges that this technology faces, including clinical trials and investors' support. Expert opinion: pSi is an outstanding material that could improve existing drug delivery and photodynamic therapies in different areas, paving the way for developing advanced theranostic nanomedicines and incorporating payloads of therapeutics with imaging capabilities. However, more extensive in-vivo studies are needed to assess the feasibility and reliability of this technology for clinical practice. The technical and commercial challenges that this technology face are still uncertain.
Nanoporous anodic alumina: A versatile platform for optical biosensors
Publisher: MDPI AG
Date: 30-05-2014
DOI: 10.3390/MA7064297
Engineering the Slow Photon Effect in Photoactive Nanoporous Anodic Alumina Gradient-Index Filters for Photocatalysis
Publisher: American Chemical Society (ACS)
Date: 25-06-2018
Abstract: In this study, we explore for the first time the capabilities of nanoporous anodic alumina gradient-index filters (NAA-GIFs) functionalized with titanium dioxide (TiO
Chemical Functionalization of Inner Walls of Carbon Nanotubes with Long-Chain Aliphatic Amines
Publisher: American Scientific Publishers
Date: 05-2017
Rational Management of Photons for Enhanced Photocatalysis in Structurally-Colored Nanoporous Anodic Alumina Photonic Crystals
Publisher: American Chemical Society (ACS)
Date: 08-01-2019
Engineering of Hybrid Nanoporous Anodic Alumina Photonic Crystals by Heterogeneous Pulse Anodization
Publisher: Springer Science and Business Media LLC
Date: 21-06-2018
DOI: 10.1038/S41598-018-27775-6
Abstract: In this study, we present an advanced nanofabrication approach, so-called ‘heterogeneous pulse anodization’ (HPA), in which galvanostatic stepwise and apodized sinusoidal pulse anodizations are combined in a single process. This novel anodization method enables the precise optical engineering of the characteristic photonic stopbands (PSBs) of nanoporous anodic alumina photonic crystals (NAA-PCs). The resulting structures are hybrid PCs (Hy-NAA-PCs) composed of distributed Bragg reflectors (DBRs) and apodized gradient-index filters (APO-GIFs) embedded within the same PC structure. The modification of various anodization parameters such as anodization period, relative and total anodization time, structural arrangement of PCs within Hy-NAA-PCs, and pore widening time allows the fine-tuning of the PSBs’ features (i.e. number, position and bandwidth of central wavelength) across the spectral regions. The effects of these fabrication parameters are systematically assessed, revealing that the positions of the characteristic transmission bands of Hy-NAA-PCs are highly controllable. Our study provides a comprehensive rationale towards the development of unique Hy-NAA-PCs with controllable optical properties, which could open new opportunities for a plethora of applications.
Optical engineering of nanoporous photonic crystals by Gaussian-Like pulse anodization
Publisher: Elsevier BV
Date: 2021
Rational engineering of nanoporous anodic alumina optical bandpass filters
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR03490J
Abstract: Herein, we present a rationally designed advanced nanofabrication approach aiming at producing a new type of optical bandpass filters based on nanoporous anodic alumina photonic crystals. The photonic stop band of nanoporous anodic alumina (NAA) is engineered in depth by means of a pseudo-stepwise pulse anodisation (PSPA) approach consisting of pseudo-stepwise asymmetric current density pulses. This nanofabrication method makes it possible to tune the transmission bands of NAA at specific wavelengths and bandwidths, which can be broadly modified across the UV-visible-NIR spectrum through the anodisation period (i.e. time between consecutive pulses). First, we establish the effect of the anodisation period as a means of tuning the position and width of the transmission bands of NAA across the UV-visible-NIR spectrum. To this end, a set of nanoporous anodic alumina bandpass filters (NAA-BPFs) are produced with different anodisation periods, ranging from 500 to 1200 s, and their optical properties (i.e. characteristic transmission bands and interferometric colours) are systematically assessed. Then, we demonstrate that the rational combination of stacked NAA-BPFs consisting of layers of NAA produced with different PSPA periods can be readily used to create a set of unique and highly selective optical bandpass filters with characteristic transmission bands, the position, width and number of which can be precisely engineered by this rational anodisation approach. Finally, as a proof-of-concept, we demonstrate that the superposition of stacked NAA-BPFs produced with slight modifications of the anodisation period enables the fabrication of NAA-BPFs with unprecedented broad transmission bands across the UV-visible-NIR spectrum. The results obtained from our study constitute the first comprehensive rationale towards advanced NAA-BPFs with fully controllable photonic properties. These photonic crystal structures could become a promising alternative to traditional optical bandpass filters based on glass and plastic.
Real-time and in situ drug release monitoring from nanoporous implants under dynamic flow conditions by reflectometric interference spectroscopy
Publisher: American Chemical Society (ACS)
Date: 14-06-2013
DOI: 10.1021/AM4013984
Abstract: Herein, we present an innovative approach to monitoring in situ drug release under dynamic flow conditions from aluminum implants featuring nanoporous anodic alumina (NAA) covers used as a model of drug-releasing implants. In this method, reflectometric interference spectroscopy (RIfS) is used to monitor in real-time the diffusion of drug from these nanoporous implants. The release process is carried out in a microfluidic device, which makes it possible to analyze drug release under dynamic flow conditions with constant refreshing of eluting medium. This setup mimics the physiological conditions of biological milieu at the implant site inside the host body. The release of a model drug, indomethacin, is established by measuring the optical thickness change with time under four different flow rates (i.e. 0, 10, 30, and 50 μL min(-1)). The obtained data are fitted by a modified Higuchi model, confirming the diffusion-controlled release mechanism. The obtained release rate constants demonstrate that the drug release depends on the flow rate and the faster the flow rate the higher the drug release from the nanoporous covers. In particular, the rate constants increase from 2.23 ± 0.02 to 12.47 ± 0.04 μg min(-1/2) when the flow rate is increased from 10 to 50 μL min(-1), respectively. Therefore, this method provides more reliable and relevant information than conventional in vitro drug release methods performed under static conditions.
Influence of surface chemistry on the ionic conductivity of vertically aligned carbon nanotube composite membranes
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA06701H
Abstract: The ionic conductivity and electrochemical properties of vertically aligned CNT composite membranes produced by template-based catalyst-free chemical vapor deposition is tuned by chemical modification of their inner surfaces using simple oxidation.
Nanoporous photonic crystals with tailored surface chemistry for ionic copper sensing
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TC04438H
Abstract: We present a study on optical and surface chemistry engineering of nanoporous photonic crystals as sensing platforms for detection of ionic copper.
Ultrasensitive nanoporous interferometric sensor for label-free detection of gold(III) ions
Publisher: American Chemical Society (ACS)
Date: 08-11-2013
DOI: 10.1021/AM403465X
Abstract: In this study, we present an ultrasensitive sensor based on nanoporous anodic alumina (NAA) for detection of gold(III) ions (Au(3+) ions) using reflectometric interference spectroscopy (RIfS). Nanoporous anodic alumina, prepared by two-step electrochemical anodization, was functionalized with 3-mercaptopropyl-tirethoxysilane (MPTES) in order to selectively detect Au(3+) ions. Thus prepared, MPTES-NAA sensors were exposed to different concentrations of Au(3+) ions ranging from 0.1 to 750 μM and the changes in the effective optical thickness (ΔEOT) were monitored in real-time. The linear range of these Au(3+) sensors was from 0.1 to 80 μM, with a lower detection limit of 0.1 μM of Au(3+) ions. Furthermore, the specificity of these MPTES-NAA sensors was validated by sequential exposure to 40 μM solutions of Fe(3+,) Mg(2+), Co(2+), Cu(2+), Ni(2+), Ag(+), and Pb(2+), resulting in negligible changes in EOT as compared to the same concentration of Au(3+) ions. Detection of Au(3+) ions in complex and environmentally and biologically relevant solvents such as tap water and phosphate buffer solution (PBS) was also successfully carried out in order to demonstrate the real-life application of these sensors. Finally, the binding isotherm for Au(3+) ions and thiol (SH) group of MPTES-NAA system was determined by fitting the changes in EOT to Freundlich and Langmuir isotherm models.
Comparing thermal strain in outdoor maintenance and indoor service workers in the mining industry during summer
Publisher: Public Library of Science (PLoS)
Date: 05-10-2023
Photoswitchable membranes based on peptide-modified nanoporous anodic alumina: Toward smart membranes for on-demand molecular transport
Publisher: Wiley
Date: 08-04-2015
Abstract: A smart and reversibly photoswitchable membrane based on an azobenzene photo-switch containing peptides attached inside the pores of nanoporous anodic alumina membranes (NAAMs) is presented. The transport of molecules of interest across the photoswitchable peptide (PSP) functionalized NAAMs can be effectively controlled and manipulated as a function of the photostationary state of the azobenzene group in a PSP.
In situ monitored engineering of inverted nanoporous anodic alumina funnels: On the precise generation of 3D optical nanostructures
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4NR01422G
Abstract: Inverted nanoporous anodic alumina funnels (INAAFs) are produced by in-depth electrochemical/thermal engineering of nanoporous anodic alumina.
Tailor-engineered plasmonic single-lattices: harnessing localized surface plasmon resonances for visible-NIR light-enhanced photocatalysis
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9CY02561H
Abstract: A platform material composed of 2D gold (Au) nanodot plasmonic single-lattices (Au-nD-PSLs) featuring tailor-engineered geometric features for visible-NIR light-driven enhanced photocatalysis is presented.
Enhancing Forbidden Light Propagation in Nanoporous Anodic Alumina Gradient-Index Filters by Alcohol Additives
Publisher: American Chemical Society (ACS)
Date: 08-12-2020
Electrochemical Engineering of Nanoporous Materials for Photocatalysis: Fundamentals, Advances, and Perspectives
Publisher: MDPI AG
Date: 25-11-2019
DOI: 10.3390/CATAL9120988
Abstract: Photocatalysis comprises a variety of light-driven processes in which solar energy is converted into green chemical energy to drive reactions such as water splitting for hydrogen energy generation, degradation of environmental pollutants, CO2 reduction and NH3 production. Electrochemically engineered nanoporous materials are attractive photocatalyst platforms for a plethora of applications due to their large effective surface area, highly controllable and tuneable light-harvesting capabilities, efficient charge carrier separation and enhanced diffusion of reactive species. Such tailor-made nanoporous substrates with rational chemical and structural designs provide new exciting opportunities to develop advanced optical semiconductor structures capable of performing precise and versatile control over light–matter interactions to harness electromagnetic waves with unprecedented high efficiency and selectivity for photocatalysis. This review introduces fundamental developments and recent advances of electrochemically engineered nanoporous materials and their application as platforms for photocatalysis, with a final prospective outlook about this dynamic field.
(Invited) Synthesis and Characterization of Photoluminescent Polymer Micro- and Nanopillar Arrays
Publisher: The Electrochemical Society
Date: 16-04-2010
DOI: 10.1149/1.3367215
Abstract: Photoluminescent micro- and nanopillars are fabricated by replication from macroporous silicon and nanoporous anodic alumina via template wetting using different conducting polymers. The geometric features of the resulting structures are characterized through environmental scanning electron microscopy. The influence of the porous dimension in the photophysical properties of the polymeric structures is investigated by absorption and emission measurements. By means of micro-X-ray diffraction we analyze the amorphous-crystalline nature of the fabricated structures. These structures can be interesting as hole conducting donors in different applications such as nanostructured solar cells and polymer light emitting diodes.
Effects of the nanostructure and fabrication process on the photoluminescence properties of PFO nanopillar arrays
Publisher: The Electrochemical Society
Date: 27-04-2012
DOI: 10.1149/1.3700427
Abstract: Photoluminescent PFO nanopillars are fabricated by replication from nanoporous anodic alumina via template wetting method at room temperature. We have studied how the nanostructure and the experimental process influence the photoluminescent properties of the obtained structures. Results show that the nanoconfinement induces chain alignment in PFO nanopillars and modifies the photoluminescent spectra. The synthesis and characterization of these ordered nanostructures have been developed in order to create a new generation of optoelectronic devices such as polymer light-emitting diodes, sensors and organic solar cells.
Label-Free Real-Time Quantification of Enzyme Levels by Interferometric Spectroscopy Combined with Gelatin-Modified Nanoporous Anodic Alumina Photonic Films
Publisher: American Chemical Society (ACS)
Date: 13-08-2015
DOI: 10.1021/ACS.ANALCHEM.5B02225
Abstract: Herein, we present an interferometric sensor based on the combination of chemically functionalized nanoporous anodic alumina photonic films (NAA-PFs) and reflectometric interference spectroscopy (RIfS) aimed to detect trace levels of enzymes by selective digestion of gelatin. The fabrication and sensing performance of the proposed sensor were characterized in real-time by estimating the changes in effective optical thickness (i.e., sensing principle) of gelatin-modified NAA-PFs (i.e., sensing element) during enzymatic digestion. The working range (WR), sensitivity (S), low limit of detection (LLoD), and linearity (R(2)) of this enzymatic sensor were established by a series of experiments with different concentrations of gelatin (i.e., specific chemical sensing element) and trypsin (i.e., analyte), a model protease enzyme with relevant implications as a biomarker in the diagnosis of several diseases. The chemical selectivity of the sensor was demonstrated by comparison of gelatin digestion by other nonspecific enzyme models such as chymotrypsin and horseradish peroxidase. Furthermore, the role of the chemical sensing element (i.e., gelatin) was assessed by using hemoglobin instead of gelatin. Finally, we demonstrated that this sensor can be readily used to establish the kinetic parameters of enzymatic reactions. The obtained results revealed that the presented sensor has a promising potential to be used as a point-of-care system for fast detection of gastrointestinal diseases at early stages.
Fabrication and characterisation of sulfur and phosphorus (S/P) co-doped carbon nanotubes
Publisher: Elsevier BV
Date: 08-2016
Engineering of Broadband Nanoporous Semiconductor Photonic Crystals for Visible-Light-Driven Photocatalysis
Publisher: American Chemical Society (ACS)
Date: 10-12-2020
Nanoporous anodic alumina for optical biosensing
Publisher: Springer International Publishing
Date: 2015
Fabrication and optimization of bilayered nanoporous anodic alumina structures as multi-point interferometric sensing platform
Publisher: MDPI AG
Date: 06-02-2018
DOI: 10.3390/S18020470
Environmental copper sensor based on polyethylenimine-functionalized nanoporous anodic alumina interferometers
Publisher: American Chemical Society (ACS)
Date: 22-02-2019
Nanoporous alumina membranes for chromatography and molecular transporting
Publisher: Springer International Publishing
Date: 2015
Drug-releasing implants: Current progress, challenges and perspectives
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TB00548A
Abstract: This review presents the different types and concepts of drug-releasing implants using new nanomaterials and nanotechnology-based devices.
Low-cost fabrication technologies for nanostructures: State-of-the-art and potential
Publisher: IOP Publishing
Date: 08-01-2015
DOI: 10.1088/0957-4484/26/4/042001
Abstract: In the last decade, some low-cost nanofabrication technologies used in several disciplines of nanotechnology have demonstrated promising results in terms of versatility and scalability for producing innovative nanostructures. While conventional nanofabrication technologies such as photolithography are and will be an important part of nanofabrication, some low-cost nanofabrication technologies have demonstrated outstanding capabilities for large-scale production, providing high throughputs with acceptable resolution and broad versatility. Some of these nanotechnological approaches are reviewed in this article, providing information about the fundamentals, limitations and potential future developments towards nanofabrication processes capable of producing a broad range of nanostructures. Furthermore, in many cases, these low-cost nanofabrication approaches can be combined with traditional nanofabrication technologies. This combination is considered a promising way of generating innovative nanostructures suitable for a broad range of applications such as in opto-electronics, nano-electronics, photonics, sensing, biotechnology or medicine.
Size- and shape-controlled synthesis of well-organised carbon nanotubes using nanoporous anodic alumina with different pore diameters
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.JCIS.2016.12.035
Abstract: This work aims at introducing the synthesis process of carbon nanotubes (CNTs) inside nanoporous anodic alumina (NAA) templates adopting a catalyst-free chemical vapor deposition (CVD) approach under different conditions. The nanotubular structure of NAA is prepared according to tow-step anodization process. This provides a unique platform to grow CNTs with precisely controlled geometric features. The structural features, crystalline structures and chemical composition of the resulting CNTs-NAA composites were systematically characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Energy-dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR) as well as Raman spectroscopy. Preparing the CNTs according to this template technique allows us to obtain nanotubes which are open at one/both end(s) with a uniform diameter (10-200nm) along the pore length (1-100μm) without using any metal catalyst.
Seasonal influence on cognitive and psycho-physiological responses to a single 11-h day of work in outdoor mine industry workers
Publisher: Informa UK Limited
Date: 12-05-2023
Nanoporous anodic alumina photonic crystals: Fundamentals, developments and perspectives
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6TC05555A
Abstract: The control of light – its coupling, splitting, modulating, and filtering – is of fundamental importance for the development of advanced, life-changing technologies, which are expected to revolutionise our society in the near future.
Integrating surface plasmon resonance and slow photon effects in nanoporous anodic alumina photonic crystals for photocatalysis
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CY00627C
Abstract: This study explores the potential of gold-coated titania-functionalized nanoporous anodic alumina distributed Bragg reflectors (Au-TiO 2 -NAA-DBRs) as platforms to enhance photocatalytic reactions by integrating “slow photons” and surface plasmon resonance (SPR).
Facile synthesis of optical microcavities by a rationally designed anodization approach: Tailoring photonic signals by nanopore structure
Publisher: American Chemical Society (ACS)
Date: 05-2015
Abstract: Structural engineering of porous anodic aluminum oxide (AAO) nanostructures by anodization has been extensively studied in the past two decades. However, the transition of this technique into the fabrication of AAO-based one-dimensional photonic crystal is still challenging. Herein, we report for the first time on the fabrication of AAO optical microcavities by a rationally designed anodization approach. In our study, two feasible methods are used to fabricate microcavities with tunable resonance peak across the visible and near-infrared spectra. Distributed Bragg reflector (DBR) nanostructures are first fabricated by pulse anodization approach, in which the anodization voltage was periodically manipulated to achieve pseudosinusoidal modulation of the effective refractive index gradient along the depth of the AAO nanostructures. Microcavities were created by creating a nanoporous layer of constant porosity between two AAO-DBR nanostructures, and by introducing a shift of the phase of the porosity gradient along the depth of AAO. The position of the resonance peak in these microcavities can be linearly tuned by means of the duration of the high voltage anodization. These optical nanostructures are sensitive to alterations of the effective media inside the nanopores. The AAO microcavity shows a central wavelength shift of 2.58 ± 0.37 nm when exposed to water vapor. Our research highlights the feasibility of anodization technique to fabricate AAO-based photonic nanostructures for advanced sensing applications.
Localized drug delivery of selenium (Se) using nanoporous anodic aluminium oxide for bone implants
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TB00125K
Abstract: Release behavior and cancer toxicity of different forms of Se loaded into nanoporous AAO were studied.
Effect of the anodization voltage on the pore-widening rate of nanoporous anodic alumina
Publisher: Springer Science and Business Media LLC
Date: 23-08-2012
Abstract: A detailed study of the pore-widening rate of nanoporous anodic alumina layers as a function of the anodization voltage was carried out. The study focuses on s les produced under the same electrolyte and concentration but different anodization voltages within the self-ordering regime. By means of ellipsometry-based optical characterization, it is shown that in the pore-widening process, the porosity increases at a faster rate for lower anodization voltages. This opens the possibility of obtaining three-dimensional nanostructured nanoporous anodic alumina with controlled thickness and refractive index of each layer, and with a refractive index difference of up to 0.24 between layers, for s les produced with oxalic acid electrolytes.
Nanoporous Alumina
Publisher: Springer International Publishing
Date: 2015
Multifunctional microspherical magnetic and pH responsive carriers for combination anticancer therapy engineered by droplet-based microfluidics
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TB00588A
Abstract: Drug loaded luminescent porous silicon diatoms and magnetic bacterial nanowires were encapsulated within pH sensitive polymer forming biodegradable microcapsules using droplet-based microfluidics for targeting colorectal cancer.
Advanced Structural Engineering of Nanoporous Photonic Structures: Tailoring Nanopore Architecture to Enhance Sensing Properties
Publisher: American Chemical Society (ACS)
Date: 03-12-2014
DOI: 10.1021/PH500316U
Electrochemical etching methods for producing porous silicon
Publisher: Springer International Publishing
Date: 2015
Structural tuning of photoluminescence in nanoporous anodic alumina by hard anodization in oxalic and malonic acids
Publisher: Springer Science and Business Media LLC
Date: 19-04-2012
Abstract: We report on an exhaustive and systematic study about the photoluminescent properties of nanoporous anodic alumina membranes fabricated by the one-step anodization process under hard conditions in oxalic and malonic acids. This optical property is analysed as a function of several parameters (i.e. hard anodization voltage, pore diameter, membrane thickness, annealing temperature and acid electrolyte). This analysis makes it possible to tune the photoluminescent behaviour at will simply by modifying the structural characteristics of these membranes. This structural tuning ability is of special interest in such fields as optoelectronics, in which an accurate design of the basic nanostructures (e.g. microcavities, resonators, filters, supports, etc.) yields the control over their optical properties and, thus, upon the performance of the nanodevices derived from them (biosensors, interferometers, selective filters, etc.)
Iron Oxide Nanowires from Bacteria Biofilm as an Efficient Visible-Light Magnetic Photocatalyst
Publisher: American Chemical Society (ACS)
Date: 26-07-2016
Abstract: Naturally produced iron oxide nanowires by Mariprofundus ferrooxydans bacteria as biofilm are evaluated for their structural, chemical, and photocatalytic performance under visible-light irradiation. The crystal phase structure of this unique natural material presents a 1-dimensional (1D) nanowire-like geometry, which is transformed from amorphous to crystalline (hematite) by thermal annealing at high temperature without changing their morphology. This study systematically assesses the effect of different annealing temperatures on the photocatalytic activity of iron oxide nanowires produced by Mariprofundus ferrooxydans bacteria. The nanowires processed at 800 °C were the most optimal for photocatalytic applications degrading a model dye (rhodamine B) in less than an hour. These nanowires displayed excellent reusability with no significant loss of activity even after 6 cycles. Kinetic studies by using hydrogen peroxide (radical generator) and isopropyl alcohol (radical scavenger) suggest that OH• is the dominant photooxidant. These nanowires are naturally produced, inexpensive, highly active, stable, and magnetic and have the potential to be used for broad applications including environmental remediation, water disinfection, and industrial catalysis.
Synthesis of Carbon Nanotube-Nanotubular Titania Composites by Catalyst-Free CVD Process: Insights into the Formation Mechanism and Photocatalytic Properties
Publisher: American Chemical Society (ACS)
Date: 18-12-2015
Abstract: This work presents the synthesis of carbon nanotubes (CNTs) inside titania nanotube (TNTs) templates by a catalyst-free chemical vapor deposition (CVD) approach as composite platforms for photocatalytic applications. The nanotubular structure of TNTs prepared by electrochemical anodization provides a unique platform to grow CNTs with precisely controlled geometric features. The formation mechanism of carbon nanotubes inside nanotubular titania without using metal catalysts is explored and explained. The structural features, crystalline structures, and chemical composition of the resulting CNTs-TNTs composites were systematically characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The deposition time during CVD process was used to determine the formation mechanism of CNTs inside TNTs template. The photocatalytic properties of CNTs-TNTs composites were evaluated via the degradation of rhodamine B, an organic model molecule, in aqueous solution under mercury-xenon Hg (Xe) l irradiation monitored by UV-visible spectroscopy. The obtained results reveal that CNTs induces a synergestic effect on the photocatalytic activity of TNTs for rhodamine B degradation, opening new opportunities to develop advanced photocatalysts for environmental and energy applications.
Photoluminescent Enzymatic Sensor Based on Nanoporous Anodic Alumina
Publisher: American Chemical Society (ACS)
Date: 10-07-2012
DOI: 10.1021/AM300648J
Abstract: Herein, we present a smart enzymatic sensor based on nanoporous anodic alumina (NAA) and its photoluminescence (PL) in the UV-visible range. The as-produced structure of NAA is functionalized and activated in order to perform the enzyme immobilization in a controlled manner. The whole process is monitored through the PL spectrum and each stage is characterized by an exclusive barcode, which is associated with the PL oscillations. This characteristic property allows us to calculate the change in the effective optical thickness that takes place after each stage. This makes it possible to accurately detect and quantify the immobilized enzyme within the NAA structure. Finally, the NAA geometry (i.e., the pore length and its diameter) is optimized to improve the enzyme immobilization and its detection inside the pores. This enzymatic sensor can give quick and accurate measurements of enzyme levels, what is crucial in clinical enzymology to prevent and detect diseases at their primary stage.
Realization of high-quality optical nanoporous gradient-index filters by optimal combination of anodization conditions
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9NR10526C
Abstract: High-quality nanoporous anodic alumina gradient-index filters are realized by sinusoidal pulse anodization under optimized anodization conditions.
Sensing and biosensing applications of nanoporous anodic alumina
Publisher: Springer International Publishing
Date: 2015
Synthesis of well-organised carbon nanotube membranes from non-degradable plastic bags with tuneable molecular transport: Towards nanotechnological recycling
Publisher: Elsevier BV
Date: 11-2013
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