ORCID Profile
0000-0001-9308-3922
Current Organisation
University of New South Wales
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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)
Nanoscale characterisation | Nanomaterials | Geospatial Information Systems | Materials engineering | Medical Devices | Nanotechnology | Sensor Technology (Chemical aspects) | Geomechanics and Resources Geotechnical Engineering | Resources Engineering and Extractive Metallurgy | Structural Engineering | Carbon sequestration science | Nanomaterials | Nanotechnology | Functional materials | Electrochemical energy storage and conversion
ANZSRC Socio-Economic Objective (SEO)
Mining and Extraction of Energy Resources not elsewhere classified | Civil Construction Planning | Diagnostic Methods | Health Status (e.g. Indicators of Well-Being) |
Related Links
Publications
DNA release dynamics from bioreducible layer-by-layer films
Publisher: American Chemical Society (ACS)
Date: 05-02-2010
DOI: 10.1021/LA904673R
Dendrimer-enabled DNA delivery and transformation of Chlamydia pneumoniae
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.NANO.2013.04.004
Abstract: The chlamydiae are important human pathogens. Lack of a genetic manipulation system has impeded understanding of the molecular bases of virulence for these bacteria. We developed a dendrimer-enabled system for transformation of chlamydiae and used it to characterize the effects of inserting the C. trachomatis plasmid into C. pneumoniae, which lacks any plasmids. The plasmid was cloned into modified yeast vector pEG(KG) and the clone complexed to polyamidoamine dendrimers, producing 50-100 nm spherical particles. HEp-2 cell cultures were infected with C. pneumoniae strain AR-39. Twenty-four hours later, medium was replaced for 3 hours with dendrimer-plasmid complexes, then removed and the medium replaced. Cultures were harvested at various times post-transformation. Real-time PCR and RT-PCR of nucleic acids from transformed cultures demonstrated plasmid replication and gene expression. The cloned plasmid was replicated and expressed in transformants over 5 passages. This system will allow study of chlamydial gene function, allowing development of novel dendrimer-based therapies. This team of investigators developed a dendrimer-enabled system for transformation of chlamydiae and successfully utilized it to characterize the effects of inserting the C. trachomatis plasmid into C. pneumonia. This system will allow study of chlamydial gene function, allowing development of novel dendrimer-based therapies.
Recent Advances in Integrating 1D Nanomaterials into Chemiresistive Gas Sensor Devices
Publisher: Wiley
Date: 06-04-2023
Abstract: There is rapid growth in the global gas sensor market driven by new regulations for industrial emission control and residential environments and increasing demand for portable devices. Nanosensors promise to be the next generation gas sensors for the direct detection of chemical species due to their ultrahigh sensitivity, fast response, ultralow weight, and low power consumption. However, transitioning nanosensors from basic research or prototype projects to commercial products encounters two major technical challenges: difficulty in scale up and inability to demonstrate real‐world use in changing humidity and temperature conditions. The advances in addressing these two technical challenges in recent literature are surveyed. The most common 1D nanomaterials in R& D for gas sensing, metal oxides, and carbon nanotubes, as well as less common metal nanowires and psudo‐1D crystals made from charge‐transfer complexes (CTCs) are included. This review delves into the specifics of each of these 1D nanomaterials for gas sensing applications, their synthesis and deposition, sensing performance, and commercial development in the last 5 years. It highlights the scalability of one‐step electrodeposition of CTC nanowires on prefabricated electrodes, at room temperature, and from solution in making gas nanosensors.
Sustained A1 Adenosine Receptor Antagonist Drug Release from Nanoparticles Functionalized by a Neural Tracing Protein
Publisher: American Chemical Society (ACS)
Date: 21-10-2021
DOI: 10.1021/ACSCHEMNEURO.1C00538
Abstract: Respiratory dysfunction is a major cause of death in people with spinal cord injury (SCI). A remaining unsolved problem in treating SCI is the intolerable side effects of the drugs to patients. In a significant departure from conventional targeted nanotherapeutics to overcome the blood-brain barrier (BBB), this work pursues a drug-delivery approach that uses neural tracing retrograde transport proteins to bypass the BBB and deliver an adenosine A1 receptor antagonist drug, 1,3-dipropyl-8-cyclopentyl xanthine, exclusively to the respiratory motoneurons in the spinal cord and the brainstem. A single intradiaphragmatic injection at one thousandth of the native drug dosage induces prolonged respiratory recovery in a hemisection animal model. To translate the discovery into new treatments for respiratory dysfunction, we carry out this study to characterize the purity and quality of synthesis, stability, and drug-release properties of the neural tracing protein (wheat germ agglutinin chemically conjugated to horseradish peroxidase)-coupled nanoconjugate. We show that the batch-to-batch particle size and drug dosage variations are less than 10%. We evaluate the nanoconjugate size against the spatial constraints imposed by transsynaptic transport from pre to postsynaptic neurons. We determine that the nanoconjugate formulation is capable of sustained drug release lasting for days at physiologic pH, a prerequisite for long-distance transport of the drug from the diaphragm muscle to the brainstem. We model the drug-release profiles using a first-order reaction model and the Noyes-Whitney diffusion model. We confirm via biological electron microscopy that the nanoconjugate particles do not accumulate in the tissues at the injection site. We define the nanoconjugate storage conditions after monitoring the solution dispersion stability under various conditions for 4 months. This study supports further development of neural tracing protein-enabled nanotherapeutics for treating respiratory problems associated with SCI.
DNA release dynamics from bioreducible poly(amido amine) polyplexes
Publisher: American Chemical Society (ACS)
Date: 12-06-2009
DOI: 10.1021/JP901835U
Mechanical properties and stability measurement of cholesterol-containing liposome on mica by atomic force microscopy
Publisher: Elsevier BV
Date: 10-2004
DNA release dynamics from reducible polyplexes by atomic force microscopy
Publisher: American Chemical Society (ACS)
Date: 08-10-2008
DOI: 10.1021/LA802088Y
pH-Controlled association of PEG-containing terpolymers of N-isopropylacrylamide and 1-vinylimidazole
Publisher: Elsevier BV
Date: 09-2005
Nanospiral formation by droplet drying: One molecule at a time
Publisher: Springer Science and Business Media LLC
Date: 05-01-2012
Abstract: The microstructural evolution and the adhesion of an Ag nanopaste screen-printed on a silicon substrate were investigated as a function of sintering temperature. Through the two thermal analysis methods, such as differential scanning calorimeter and thermo-gravimetric analysis, the sintering conditions were defined where the temperature was raised from 150°C to 300°C, all with a fixed sintering time of 30 min. The microstructure and the volume of the printed Ag nanopaste were observed using a field emission scanning electron microscope and a 3-D surface profiler, respectively. The apparent density of the printed Ag nanopaste was calculated depending on the sintering conditions, and the adhesion was evaluated by a scratch test. As the sintering temperature increased from 150°C to 300°C, the apparent density and the adhesion increased by 22.7% and 43%, respectively. It is confirmed that the printed Ag nanopaste sintered at higher temperatures showed higher apparent density in the microstructural evolution and void aggregation, resulting in the lower electrical resistivity and various scratched fractures.
Rectification in nanoscale devices based on an asymmetric five-coordinate iron(III) phenolate complex
Publisher: Wiley
Date: 14-10-2013
Transfection activity of layer-by-layer plasmid DNA/poly(ethylenimine) films deposited on PLGA microparticles
Publisher: Elsevier BV
Date: 05-01-2009
Secretion induces cell pH dynamics impacting assembly-disassembly of the fusion protein complex: A combined fluorescence and atomic force microscopy study
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.SEMCDB.2017.08.003
Abstract: A wide range of cellular activities including protein folding and cell secretion, such as neurotransmission or insulin release, are all governed by intracellular pH homeostasis, underscoring the importance of pH on critical life processes. Nano- scale pH measurements of cells and biomolecules therefore hold great promise in understanding a plethora of cellular functions, in addition to disease detection and therapy. In the current study, a novel approach using cadmium telluride quantum dots (CdTeQDs) as pH sensors, combined with fluorescent imaging, spectrofluorimetry, atomic force microscopy (AFM), and Western blot analysis, enabled the study of intracellular pH dynamics at 1 milli-pH sensitivity and 80nm pixel resolution, during insulin secretion. Additionally, the pH-dependent interaction between membrane fusion proteins, also called the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE), was determined. Glucose stimulation of CdTeQD-loaded insulin secreting Min-6 mouse insulinoma cell line demonstrated the initial (5-6min) intracellular acidification reflected as a loss in QD fluorescence, followed by alkalization and a return to resting pH in 10min. Analysis of the SNARE complex in insulin secreting Min-6 cells demonstrated an initial gain followed by loss of complexed SNAREs in 10min. Stabilization of the SNARE complex at low intracellular pH is further supported by results from studies utilizing both native and AFM measurements of liposome-reconstituted recombinant neuronal SNAREs, providing a molecular understanding of the role of pH during cell secretion.
Immobilization and molecular interactions between bacteriophage and lipopolysaccharide bilayers
Publisher: American Chemical Society (ACS)
Date: 18-05-2010
DOI: 10.1021/LA1013413
Abstract: The paper describes immobilization methods of bacteriophage P22 and tailspike gp9 proteins isolated from P22 on atomic force microscope (AFM) probes. The paper also reports single molecule force spectroscopy (SMFS) using AFM of the immobilized P22 (or gp9) interactions with substrate-supported O-antigenic lipopolysaccharides (LPS) bilayers. LPS covers the outer membrane of gram-negative bacteria, such as Salmonella typhimurium. Evidence from AFM imaging and SMFS shows that immobilized P22 (or gp9) are capable of strong and multivalent binding to supported LPS. The most common rupture forces between P22 and LPS were identified to be 72, 130, 206, and 279 pN at force loading rate of 12,000 pN/s. The quantized unbinding force was found to decrease with decreasing force loading rate as predicted by the Bell model. By fitting the force data with the Bell model, an energy barrier of 55 kJ/mol was obtained. Evidence is also provided that demonstrates the resilience of phage to pH and temperature fluctuation as well as dehydration/rehydration cycles. The biospecific interactions between P22 and the LPS are relevant to cell infection, inflammation, cancer progression and metastasis, food safety, pharmaceuticals, and biosensor development.
Gene delivery in vitro and in vivo from bioreducible multilayered polyelectrolyte films of plasmid DNA
Publisher: Elsevier BV
Date: 02-2009
Fibronectin Adsorption to Nanopatterned Silicon Surfaces
Publisher: Hindawi Limited
Date: 2008
DOI: 10.1155/2008/543170
Abstract: The possibility of using surface topography for guidance of different biological molecules and cells is a relevant topic that can be applied to a wide research activity. This study investigated the adsorption of fibronectin to a diffraction grated silicon surface. The rectangular grating profile featured a controlled surface with 350 nm period and a corrugation depth of 90 nm. Results demonstrated that the controlled surface had a significantly positive effect on the fibronectin binding. Thus, nanoscale surface topography can enhance fibronectin binding.
Cross-linked bioreducible layer-by-layer films for increased cell adhesion and transgene expression
Publisher: American Chemical Society (ACS)
Date: 06-04-2010
DOI: 10.1021/JP100486H
Dually responsive multiblock copolymers via reversible addition- fragmentation chain transfer polymerization: Synthesis of temperature- and redox-responsive copolymers of poly(N-isopropylacrylamide) and poly(2-(dimethylamino)ethyl methacrylate)
Publisher: American Chemical Society (ACS)
Date: 30-10-2007
DOI: 10.1021/MA071176P
Sleep disordered breathing induced by cervical spinal cord injury and effect of adenosine A1 receptors modulation in rats
Publisher: American Physiological Society
Date: 12-2019
DOI: 10.1152/JAPPLPHYSIOL.00563.2019
Abstract: Sleep-disordered breathing (SDB) is very common after spinal cord injury (SCI). The present study was designed to evaluate the therapeutic efficacy of adenosine A1 receptor blockade (8-cyclopentyl-1,3-dipropylxanthine, DPCPX) on SDB in a rodent model of SCI. We hypothesized that SCI induced via left hemisection of the second cervical segment (C2Hx) results in SDB. We further hypothesized that blockade of adenosine A1 receptors following C2Hx would reduce the severity of SDB. In the first experiment, adult male rats underwent left C2Hx or sham (laminectomy) surgery. Unrestrained whole body plethysmography (WBP) and implanted wireless electroencephalogram (EEG) were used for assessment of breathing during spontaneous sleep and for the scoring of respiratory events at the acute (~1 wk), and chronic (~6 wk) time points following C2Hx. During the second experiment, the effect of oral administration of adenosine A1 receptor antagonist (DPCPX, 3 times a day for 4 days) on SCI induced SDB was assessed. C2Hx animals exhibited a higher apnea-hypopnea index (AHI) compared with the sham group, respectively (35.5 ± 12.6 vs. 19.1 ± 2.1 events/h, P 0.001). AHI was elevated 6 wk following C2Hx ( week 6, 32.0 ± 5.0 vs. week 1, 42.6 ± 11.8 events/h, respectively, P = 0.12). In contrast to placebo, oral administration of DPCPX significantly decreased AHI 4 days after the treatment (159.8 ± 26.7 vs. 69.5 ± 8.9%, P 0.05). Cervical SCI is associated with the development of SDB in spontaneously breathing rats. Adenosine A1 blockade can serve as a therapeutic target for SDB induced by SCI. NEW & NOTEWORTHY The two key novel findings of our study included that 1) induced cervical spinal cord injury results in sleep-disordered breathing in adult rats, and 2) oral therapy with an adenosine A1 receptor blockade using DPCPX is sufficient to significantly reduce apnea-hypopnea index following induced cervical spinal cord injury.
Deposition and aggregation of aspirin molecules on a phospholipid bilayer pattern
Publisher: American Chemical Society (ACS)
Date: 22-12-2005
DOI: 10.1021/LA047802I
Abstract: Aspirin and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE) are deposited from their alcoholic mixed solution onto highly oriented pyrolytic graphite (HOPG) by spin coating. The film structure and morphology are characterized by atomic force microscopy (AFM). The barely soluble DMPE forms a highly oriented stripe phase as a result of its one-dimensional epitaxy with the HOPG lattice. The bilayer stripe pattern exposes the cross section of the lipid bilayer lamellae and enables the direct visualization of the molecular interactions of drug or biological molecules with either the hydrophobic or the hydrophilic part of the phospholipid bilayer. The bilayer pattern affects the aspirin molecular deposition and aggregation. AFM shows that the aspirin molecules prefer to deposit and aggregate along the aliphatic interior part of the bilayer pattern, giving rise to parallel dimer rods in registry with the underlying pattern. The nonpolar interactions between aspirin and the phospholipid bilayer are consistent with the lipophilic nature of aspirin. The bilayer pattern not only stabilizes the rodlike aggregate structure of aspirin at low aspirin concentration but also inhibits crystallization of aspirin at high aspirin concentration. Molecular models show that the width of the DMPE aliphatic chain interior can accommodate no more than two aspirin dimers. The bilayer confinement may prevent aspirin from reaching its critical nucleus size. This study illustrates a general method to induce a metastable or amorphous form of an active pharmaceutical ingredient (API) by chemical confinement under high undercooling conditions. Metastable and amorphous solids often display better solubility and bioavailability than the stable crystalline form of the API.
Surfactant - Polymer nanoparticles enhance the effectiveness of anticancer photodynamic therapy
Publisher: American Chemical Society (ACS)
Date: 23-07-2008
DOI: 10.1021/MP800026T
Abstract: Photodynamic therapy (PDT) is a promising treatment modality for cancer. PDT is based on the concept that photosensitizers, when exposed to light of specific wavelength, generate cytotoxic reactive oxygen species (ROS) capable of killing tumor cells. The effectiveness of PDT has been limited in part by the lack of photosensitizers that accumulate sufficiently in tumor cells and poor yield of ROS from existing photosensitizers. In this report, we investigated whether aerosol OT-alginate nanoparticles can be used as a carrier to enhance the therapeutic efficacy of a model photosensitizer, methylene blue. Methylene blue loaded nanoparticles were evaluated for PDT effectiveness in two cancer cell lines, MCF-7 and 4T1. Encapsulation of methylene blue in nanoparticles significantly enhanced intracellular ROS production, and the overall cytotoxicity following PDT. It also resulted in higher incidence of necrosis. Greater effectiveness of nanoparticles could be correlated with higher yield of ROS with nanoparticle-encapsulated methylene blue. Further, treatment of tumor cells with nanoparticle-encapsulated methylene blue resulted in significant nuclear localization of methylene blue while free drug treatment resulted in its accumulation mainly in the endolysosomal vesicles. In conclusion, encapsulation of methylene blue in aerosol OT-alginate nanoparticles enhanced its anticancer photodynamic efficacy in vitro. Increased ROS production and favorable alteration in the subcellular distribution contribute to the enhanced PDT efficacy of nanoparticle-encapsulated photosensitizer.
Nanospiral Formation by Droplet Drying: One Molecule at a Time
Publisher: Springer Science and Business Media LLC
Date: 30-09-2011
DOI: 10.1007/S11671-010-9793-9
Abstract: We have created nanospirals by self-assembly during droplet evaporation. The nanospirals, 60–70 nm in diameter, formed when solvent mixtures of methanol and m -cresol were used. In contrast, spin coating using only methanol as the solvent produced epitaxial films of stripe nanopatterns and using only m -cresol disordered structure. Due to the disparity in vapor pressure between the two solvents, droplets of m -cresol solution remaining on the substrate serve as templates for the self-assembly of carboxylic acid molecules, which in turn allows the visualization of solution droplet evaporation one molecule at a time.
Controlled permeability in polyelectrolyte films via solvent treatment
Publisher: American Chemical Society (ACS)
Date: 10-09-2005
DOI: 10.1021/CM051090F
Disassembly of layer-by-layer films of plasmid DNA and reducible TAT polypeptide
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.BIOMATERIALS.2006.08.035
Abstract: This paper reports the disassembly of layer-by-layer (LbL) films of plasmid DNA and a reducible cationic polypeptide. To utilize a reducing microenvironment of cellular plasma membrane as a potential trigger, LbL films are assembled to contain both DNA and the TAT-based polypeptide (PTAT) with reducible disulfide bonds in the backbone. The assembly and disassembly processes are monitored by goniometry, ellipsometry, and atomic force microscopy (AFM). The structure of the PTAT films is compared with that of non-reducible poly(L-lysine) (PLL) films. Both PTAT and PLL films exhibit exponential growth but with the contact angle alternating between characteristic values. Ellipsometry and AFM show a gradual and complete disassembly of the PTAT but not the PLL films in a 24h period in the reducing environment in vitro. This study suggests a potential of using reducible LbL films for controlled DNA delivery.
Temperature-reversible ultrathin films of N-isopropylacrylamide terpolymer adsorbed at the solid-liquid interface
Publisher: American Chemical Society (ACS)
Date: 27-10-2007
DOI: 10.1021/LA701819Q
Abstract: This article describes the stability and reversibility of ultrathin films of N-isopropylacrylamide (NIPA)-vinylimidazole (VI)-poly(ethylene glycol) (PEG) graft terpolymer adsorbed at the solid-liquid interface upon temperature cycling from below to above its phase transition temperature. The coil-to-globule and globule-to-coil phase transitions were captured by in situ fluid tapping atomic force microscopy (AFM). The film thickness of 1 nm was determined by AFM, X-ray photoelectron spectroscopy, and X-ray reflectivity. The concentration required to reach full coverage was found to be higher when adsorption occurred below the phase transition temperature. From 23 to 42 degrees C, the adsorbed NIPA terpolymer film was observed to be molecularly smooth, corresponding to the close-packed structure of flexible polymer coils. Particles containing between one and a few globules appeared abruptly at the interface at 42-43 degrees C, the same temperature as the solution phase transition temperature, which was determined by dynamic light scattering. The size of the particles did not change with temperature, whereas the number of particles increased with increasing temperature up to 60 degrees C. The particles correspond to the collapsed and associated state of the globules. The film morphological changes were found to be reversible upon temperature cycling. Subtle differences were observed between dip-coated and spin-coated films that are consistent with a higher degree of molecular freedom for spin-coated films. The study contributes to the fundamental understanding and applications of smart ultrathin films and coatings.
Multifunctional dendrimer-templated antibody presentation on biosensor surfaces for improved biomarker detection
Publisher: Wiley
Date: 27-01-2010
Nano-delivery of RAD6/translesion synthesis inhibitor SMI#9 for triple-negative breast cancer therapy
Publisher: American Association for Cancer Research (AACR)
Date: 12-2018
DOI: 10.1158/1535-7163.MCT-18-0364
Abstract: The triple-negative breast cancer (TNBC) subtype, regardless of their BRCA1 status, has the poorest outcome compared with other breast cancer subtypes, and currently there are no approved targeted therapies for TNBC. We have previously demonstrated the importance of RAD6-mediated translesion synthesis pathway in TNBC development rogression and chemoresistance, and the potential therapeutic benefit of targeting RAD6 with a RAD6-selective small-molecule inhibitor, SMI#9. To overcome SMI#9 solubility limitations, we recently developed a gold nanoparticle (GNP)-based platform for conjugation and intracellular release of SMI#9, and demonstrated its in vitro cytotoxic activity toward TNBC cells. Here, we characterized the in vivo pharmacokinetic and therapeutic properties of PEGylated GNP-conjugated SMI#9 in BRCA1 wild-type and BRCA1-mutant TNBC xenograft models, and investigated the impact of RAD6 inhibition on TNBC metabolism by 1H-NMR spectroscopy. GNP conjugation allowed the released SMI#9 to achieve higher systemic exposure and longer retention as compared with the unconjugated drug. Systemically administered SMI#9-GNP inhibited the TNBC growth as effectively as intratumorally injected unconjugated SMI#9. Inductively coupled mass spectrometry analysis showed highest GNP concentrations in tumors and liver of SMI#9-GNP and blank-GNP–treated mice however, tumor growth inhibition occurred only in the SMI#9-GNP–treated group. SMI#9-GNP was tolerated without overt signs of toxicity. SMI#9-induced sensitization was associated with perturbation of a common set of glycolytic pathways in BRCA1 wild-type and BRCA1-mutant TNBC cells. These data reveal novel SMI#9 sensitive markers of metabolic vulnerability for TNBC management and suggest that nanotherapy-mediated RAD6 inhibition offers a promising strategy for TNBC treatment.
Incorporation of phospholipids enhances cellular uptake and retention of surfactant-polymer nanoparticles
Publisher: American Scientific Publishers
Date: 09-2007
DOI: 10.1166/JBN.2007.040
Nanostructure fabrication using nanosphere lithography for photonics devices
Publisher: IEEE
Date: 2006
Statistical study of two-dimensional colloidal crystals based on microscopic images and optical diffraction
Publisher: Elsevier BV
Date: 11-2000
Surface functionalization of mesoporous silica nanoparticles controls loading and release behavior of mitoxantrone
Publisher: Springer Science and Business Media LLC
Date: 04-05-2012
DOI: 10.1007/S11095-012-0766-9
Abstract: To investigate the effect of surface functionalization of mesoporous silica nanoparticles (MSN) on crystallization, loading, release and activity of mitoxantrone (MTX). Thiol-, amine-, and mixed thiol/amine-functionalized MSN were synthesized and characterized by electron microscopy, thermogravimetry, surface area analysis, elemental analysis and zeta potential. MTX loading and release kinetics were determined in phosphate and acetate buffers (pH 7.4 and 4.5). The crystalline state of MTX in MSN was determined by differential scanning calorimetry and X-ray diffraction. Cytotoxicity and activity of MTX loaded MSN were determined by MTS assay in MDA-MB-231 cells. Our results demonstrate that loading of MTX depends strongly on the type of surface functional groups in MSN. Thiol-MSN showed the highest MTX loading (18 % w/w) when compared with thiol/amine-MSN (6 % w/w) and amine-MSN (1 % w/w). MTX release was strongly dependent on the pH of the release medium and the type of surface functional group. MTX was found in the amorphous form when loaded in thiol-functionalized MSN. No significant effect of surface modification of MSN on particle toxicity was observed. MTX loaded in MSN exhibited comparable anticancer activity in vitro as free MTX. Surface modifications of MSN have significant effect on MTX crystallization and release behavior.
Liquid-Metal-Assisted Deposition and Patterning of Molybdenum Dioxide at Low Temperature
Publisher: American Chemical Society (ACS)
Date: 11-2021
Diaphragmatic recovery in rats with cervical spinal cord injury induced by a theophylline nanoconjugate: Challenges for clinical use
Publisher: Informa UK Limited
Date: 07-03-2019
Stepwise adsorption of a long trichlorosilane and a short aminosilane
Publisher: Elsevier BV
Date: 03-2000
Asymmetrical molecular aggregation in spherulitic dye films
Publisher: American Chemical Society (ACS)
Date: 24-03-1999
DOI: 10.1021/JA983842V
Size‐Dependent Penetration of Nanoparticles in Tumor Spheroids: A Multidimensional and Quantitative Study of Transcellular and Paracellular Pathways
Publisher: Wiley
Date: 11-10-2023
Polystyrene nanorod formation in C12 E5 hemimicelle thin film templates
Publisher: Springer Science and Business Media LLC
Date: 30-09-2005
Radiation and Gold Nanoparticle Immunomodulation in MDA MB 231 Mouse Breast Cancer Model
Publisher: Elsevier BV
Date: 11-2020
Resolving the Thickness and Micromechanical Properties of Lipid Bilayers and Vesicles Using AFM
Publisher: Wiley
Date: 04-11-2005
Colloidal subwavelength nanostructures for antireflection optical coatings
Publisher: Optica Publishing Group
Date: 15-07-2005
DOI: 10.1364/OL.30.001885
Abstract: A two-dimensional (2D) subwavelength nanostructure for antireflection coating is fabricated upon a transparent substrate. Self-assembled 2D colloidal crystals are used as a nanoscale composite material with controlled thickness and low refractive index. The feature size of the structure is approximately 105 nm. The structure is used for antireflection coating, and the measured reflectivity of a glass substrate is reduced to 0.3%. Enhanced transmission through the substrate is also observed.
Examining the inflammatory response to nanopatterned polydimethylsiloxane using organotypic brain slice methods
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.JNEUMETH.2013.04.023
Abstract: A long-term effect of chronically implanted neural electrodes is the formation of a glial scar made up of reactive astrocytes, microglia and the matrix proteins they generate. Studies have shown glial fibrillary acidic protein (GFAP) and cytokines interleukin-1beta (IL-1β), tumor necrosis factor alpha (TNFα), and transforming growth factor beta 1 (TGFβ1) are involved with the initial and modulation phases of reactive astrogliosis. In the present study, nanopatterning of polydimethylsiloxane (PDMS) was attempted as a method for reducing the inflammatory response of glial cells. A unique feature of this study is the use of in vitro brain slice cultures (organotypic cultures) in order to more accurately depict the native response. The aim of the study was to determine whether nanotopography could reduce inflammatory signals typically resultant from neural electrode implantation. Specifically, observation of cell alignment and surveillance of GFAP, IL-1β, TNFα, and TGFβ1 gene expression around the PDMS pins was performed. Results of this study confirm nanopatterning not only influences cell morphology, but some of the molecular signals as well. These results collectively indicate nanopatterning improves the biocompatibility of PDMS by reducing inflammatory markers such as GFAP, IL-1β, TGFβ1 and TNFα compared to the non-patterned PDMS pins.
Influence of Nanoscale Surface Roughness on Colloidal Force Measurements
Publisher: American Chemical Society (ACS)
Date: 14-09-2015
DOI: 10.1021/ACS.LANGMUIR.5B02672
Abstract: Forces between colloidal particles determine the performances of many industrial processes and products. Colloidal force measurements conducted between a colloidal particle AFM probe and particles immobilized on a flat substrate are valuable in selecting appropriate surfactants for colloidal stabilization. One of the features of inorganic fillers and extenders is the prevalence of rough surfaces-even the polymer latex particles, often used as model colloidal systems including the current study, have rough surfaces albeit at a much smaller scale. Surface roughness is frequently cited as the reason for disparity between experimental observations and theoretical treatment but seldom verified by direct evidence. This work reports the effect of nanoscale surface roughness on colloidal force measurements carried out in the presence of surfactants. We applied a heating method to reduce the mean surface roughness of commercial latex particles from 30 to 1 nm. We conducted force measurements using the two types of particles at various salt and surfactant concentrations. The surfactants used were pentaethylene glycol monododecyl ether, Pluronic F108, and a styrene/acrylic copolymer, Joncryl 60. In the absence of the surfactant, nanometer surface roughness affects colloidal forces only in high salt conditions when the Debye length becomes smaller than the surface roughness. The adhesion is stronger between colloids with higher surface roughness and requires a higher surfactant concentration to be eliminated. The effect of surface roughness on colloidal forces was also investigated as a function of the adsorbed surfactant layer structure characterized by AFM indentation and dynamic light scattering. We found that when the layer thickness exceeds the surface roughness, the colloidal adhesion is less influenced by surfactant concentration variation. This study demonstrates that surface roughness at the nanoscale can influence colloidal forces significantly and should be taken into account in colloidal dispersion formulations.
Phospholipid nanoparticles: Process optimization using factorial design and atomic force microscopy
Publisher: American Scientific Publishers
Date: 12-2007
DOI: 10.1166/JBN.2007.052
RAD6B Loss Disrupts Expression of Melanoma Phenotype in Part by Inhibiting WNT/β-Catenin Signaling
Publisher: Elsevier BV
Date: 02-2021
Nanoscale aggregate structures of trisiloxane surfactants at the solid-liquid interface
Publisher: American Chemical Society (ACS)
Date: 28-02-2004
DOI: 10.1021/LA036059B
Abstract: The self-associating structures at the solid-liquid interface of three nonionic trisiloxane surfactants ((CH3)3SiO)2Si(CH3)(CH2)3(OCH2CH2)n OH (n = 6, 8, and 12), or BEn, are studied as a function of substrate properties by atomic force microscopy (AFM) imaging and force measurement. These trisiloxane surfactants are known as superwetters, which promote rapid spreading of dilute aqueous solutions on low-energy surfaces. This study also attempts to relate the BEn surface aggregate structures at the solid-liquid interface to their superwetting behavior. Four substrates are used in the study: muscovite mica, highly oriented pyrolytic graphite, and oxidized silicon wafer with and without a full monolayer of self-assembled n-octadecyltrichlorosilane (OTS). The concentration of BEn is fixed at 2 times the critical aggregation concentration (CAC). The BEn surfactants are only weakly attracted to hydrophilic surfaces, more on oxidized silicon than on mica. All three form ordinary planar monolayers on HOPG and OTS-covered oxidized silicon. The significance of surfactant adsorption on the AFM tip is investigated by comparing the force curves obtained by tips with and without thiol modification. The surface aggregate structures of the BEn surfactants correlate with their bulk structures and do not exhibit anomalous adsorption behavior. The adsorption behavior of the BEn superwetters is similar to that of the CmEn surfactants. Thus, our results confirm previous work showing that superwetting shares its main features with other classes of surfactants.
The secretion and biological function of tumor suppressor maspin as an exosome cargo protein
Publisher: Impact Journals, LLC
Date: 11-11-2017
Application of virtual laboratories and molecular simulations in teaching nanoengineering to undergraduate students
Publisher: Wiley
Date: 28-06-2018
DOI: 10.1002/CAE.21940
Surface forces measurements on a cationic polymer in the presence of an anionic ???
Publisher: Elsevier BV
Date: 12-1991
Radiation and Gold Nanoparticle Increase the Expression of Immunogenic Cell Death Markers in MDA MB 231 Breast Cancer Model
Publisher: Elsevier BV
Date: 10-2020
From ribbons to nanodot arrays: Nanopattern design through reductive annealing
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B514595C
Abstract: A new approach to the generation of nanoparticle arrays in periodic as well as non-periodic fashions has been discovered based on reduction of oxidized nanoscroll/nanoribbon precursors in the transmission electron microscope (carbothermal reduction) or by hydrogen annealing. Arrays consisting of nickel arsenide nanoparticles of size 3-4 nm have been generated.
In situ AFM analysis investigating disassembly of DNA nanoparticles and nano-films
Publisher: Humana Press
Date: 14-09-2013
DOI: 10.1007/978-1-62703-140-0_13
Abstract: Synthetic vector-based gene delivery systems continue to gain strength as viable alternatives to viral vectors due to safety and other concerns. DNA release dynamics is key to the understanding and control of gene delivery from nano-systems. Here we describe atomic force microscope application to the understanding of DNA release dynamics from bioreducible polycation-based nano-systems. The two nano-systems are polyplex nanoparticles and layer-by-layer films.
Liver-Targeted gene delivery through retrograde intrabiliary infusion
Publisher: Humana Press
Date: 14-09-2013
DOI: 10.1007/978-1-62703-140-0_19
Abstract: Retrograde intrabiliary infusion (RII) has recently been characterized as a safe and effective administration route for liver-targeted gene delivery. Efficient transgene expression in the liver has been achieved by infusing a variety of gene vectors including adenovirus, retrovirus, lipoplexes, polyplexes, and naked DNA through the common bile duct. Here, we describe the RII technique and key infusion parameters for delivering plasmid DNA and DNA nanoparticles to the rat liver. After RII of plasmid DNA, the level of transgene expression in rat liver is comparable to that achieved by hydrodynamic injection of plasmid DNA, which is considered to be "gold standard" for liver-targeted gene delivery. RII has also been shown to significantly enhance the gene delivery efficiency by polymer/DNA nanoparticles in comparison with intravenous and intraportal infusions. This method induces minimal level of cytotoxicity and damage to the liver and bile duct. Due to these advantages, RII has the potential to be used for delivering various gene vectors in clinical setting through the endoscopic retrograde cholangiopancreatography procedure.
Dendrimer-enabled transformation of Chlamydia trachomatis
Publisher: Elsevier BV
Date: 12-2013
DOI: 10.1016/J.MICPATH.2013.08.003
Abstract: Lack of a system for genetic manipulation of Chlamydia trachomatis has been a key challenge to advancing understanding the molecular genetic basis of virulence for this bacterial pathogen. We developed a non-viral, dendrimer-enabled system for transformation of this organism and used it to characterize the effects of inserting the common 7.5 kbp chlamydial plasmid into strain L2(25667R), a C. trachomatis isolate lacking it. The plasmid was cloned in pUC19 and the clone complexed to polyamidoamine dendrimers, producing ∼83 nm spherical particles. Nearly confluent McCoy cell cultures were infected with L2(25667R) and reference strain L2(434). At 16 h post-infection, medium was replaced with dendrimer-plasmid complexes in medium lacking additives (L2(25667R)) or with additive-free medium alone (L2(434)). Three h later complexes/buffer were removed, and medium was replaced cultures were harvested at various times post-transformation for analyses. Real time PCR and RT-PCR of nucleic acids from transformed cultures demonstrated plasmid replication and gene expression. A previous report indicated that one or more plasmid-encoded product govern(s) transcription of the glycogen synthase gene (glgA) in standard strains. In L2(25667R) the gene is not expressed, but transformants of that strain given the cloned chlamydial plasmid increase glgA expression, as does L2(434). The cloned plasmid is retained, replicated, and expressed in transformants over at least 5 passages, and GFP is expressed when transformed into growing L2(25667R). This transformation system will allow study of chlamydial gene function in pathogenesis.
A supra-monolayer nanopattern for organic nanoparticle array deposition
Publisher: American Chemical Society (ACS)
Date: 25-03-2013
DOI: 10.1021/AM400181W
Abstract: Nanopatterns have applications in many areas including sensors, optoelectronics, and crystallization screening. Particle lithography is a convenient method to manufacture nanoring nanopatterns based on organosilane surface chemistry. The pattern thickness is generally limited to the monolayer thickness. This work is focused on the chemical vapor deposition conditions that yield nanopatterns with multilayer thickness. The supra-monolayer n-octadecyltrichlorosilane (OTS) nanoring patterns are made using polystyrene particle lithography. The supra-monolayer nanopatterns are used as "nano-flasks" to deposit and nucleate nanoparticles of small organic molecules including n-docosane, aspirin, and clarithromycin. The supra-monolayer OTS nanopattern is an effective template for nanoparticle array deposition of all three chemicals with high degree of fidelity to the substrate pattern. The nanoparticle size is varied by solution concentration. The preferential deposition of the organic molecules inside the nanoring is attributed to the dewetting of the liquid film on the nanopattern. The dewetting process effectively distributes the liquid film among the "nano-flasks" so that millions of solution experiments can be carried out in isolated droplets with droplet volume as small as 1×10(-10) nL. The research demonstrates a method to manufacture "nano-flask" arrays for high-throughput nanoparticle deposition trials and manufacture of monodisperse organic/drug nanoparticles through self-assembly.
Monolayers of Bolaform Amphiphiles: Influence of Alkyl Chain Length and Counterions
Publisher: American Chemical Society (ACS)
Date: 11-1994
DOI: 10.1021/LA00023A044
ENATBIO: a National Conference on Emerging Nanoscience in Technology and Biomedicine
Publisher: Elsevier BV
Date: 12-2008
Gas nanosensors for health and safety applications in mining
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/D3NA00507K
Gold nanostructures: synthesis, properties, and neurological applications
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1CS01111A
Abstract: Recent advances in nanotechnology are expected to increase our current understanding of neuroscience.
Particle-rod hybrids: Growth of arachidic acid molecular rods from capped cadmium selenide nanoparticles
Publisher: American Chemical Society (ACS)
Date: 25-11-2004
DOI: 10.1021/JA045011X
Abstract: This communication describes a spin-coating method to nucleate organic molecular rods of uniform size from an inorganic nanoparticle at a solid surface. The particle-rod hybrid structure spontaneously forms when a film is spin coated from a mixed 2-propanol solution of arachidic acid (AA) and nanoparticles of cadmium selenide capped by mercaptoundecanoic acid (MUA-CdSe) on graphite. AFM images show that MUA-CdSe nanoparticles nucleate single crystalline rods of AA with a cross section of a single unit cell of the C-form. The solution-based process potentially allows the precise tuning of the wetting profile of the solution on the surface-attached nanoparticle, which provides the reservoir for the growth of the single crystalline rods. The results suggest that nanoparticles can be regarded as nanoseeds for the nucleation of guest crystals. It should be possible to further functionalize the AA rods by electrostatic complexation with metal or organic ions.
Hyaluronic acid-conjugated polyamidoamine dendrimers for targeted delivery of 3,4-difluorobenzylidene curcumin to CD44 overexpressing pancreatic cancer cells
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.COLSURFB.2015.09.043
Abstract: The current study was aimed to develop a targeted dendrimer formulation of 3, 4-difluorobenzylidene curcumin (CDF) and evaluate its potential in CD44 targeted therapy for pancreatic cancer. Using amine terminated fourth generation poly(amidoamine) (PAMAM) dendrimer nanocarrier and hyaluronic acid (HA) as a targeting ligand, we engineered a CD44-targeted PAMAM dendrimer (HA-PAMAM) formulation of CDF. The resulting dendrimer nanosystem (HA-PAMAM-CDF) had a particle size and surface charge of 9.3 ± 1.5 nm and -7.02 ± 9.53 mV, respectively. When CD44 receptor overexpressing MiaPaCa-2 and AsPC-1 human pancreatic cancer cells were treated with HA-PAMAM-CDF, a dose-dependent cytotoxicity was observed. Furthermore, blocking the CD44 receptors present on the MiaPaCa-2 cells using free excess soluble HA prior to treatment with HA-PAMAM-CDF nano-formulation resulted in 1.71 fold increase in the IC50 value compared to non-targeted formulation (PAMAM-CDF), confirming target specificity of HA-PAMAM-CDF. Additionally, HA-PAMAM-CDF formulation when compared to PAMAM-CDF, displayed higher cellular uptake in MiaPaCa-2 cancer cell lines as shown by fluorescence studies. In summary, the novel CD44 targeted dendrimer based nanocarriers appear to be proficient in mediating site-specific delivery of CDF via CD44 receptors, with an improved therapeutic margin and safety.
Interactions, Structure, and Stability of Photoreactive Bolaform Amphiphile Multilayers
Publisher: American Chemical Society (ACS)
Date: 03-1995
DOI: 10.1021/LA00003A043
Direct force measurement of silicone- and hydrocarbon-based ABA triblock surfactants in alcoholic media by atomic force microscopy
Publisher: Elsevier BV
Date: 12-2002
Thermal characterization of the interaction of silanes with a dihydroxy vulcanized fluoroelastomer
Publisher: Rubber Division, ACS
Date: 11-2006
DOI: 10.5254/1.3547965
Abstract: The reactivity of aminosilane and vinylsilane with a dihydroxy (Bisphenol AF) crosslinkable fluoroelastomer containing only vinylidene fluoride (VF2) and hexafluoropropylene (HFP) was monitored using Differential Scanning Calorimetry (DSC) and X-ray Photoelectron Spectroscopy (XPS). The DSC results showed that the introduction of an aminosilane, or a combination of aminosilane and vinylsilane solutions, to the cure system of the fluoroelastomer resulted in a peak shift. This shift indicates that crosslinking in fluoroelastomer-silane system occurs at a lower temperature when aminosilane is present. Results also confirm that the organofunctional group on the silane reacts with the elastomer. XPS analysis of the silane-coated fluoroelastomer heated at 120 °C, 160 °C and 200 °C reveals that dehydrofluorination of the polymer is one of the steps in the reaction. It is our hypothesis that the amine group on the aminosilane is a contributor to the dehydrofluorination of the fluoroelastomer.
Therapeutic enhancement of radiation and immunomodulation by gold nanoparticles in triple negative breast cancer
Publisher: Informa UK Limited
Date: 18-01-2021
In situ AFM analysis investigating disassembly of DNA nanoparticles and nanofilms
Publisher: Springer New York
Date: 2019
DOI: 10.1007/978-1-4939-9092-4_13
Abstract: Synthetic vector-based gene delivery continues to gain strength as viable alternatives to viral vectors due to safety and other concerns. DNA release dynamics is key to the understanding and control of gene delivery from nanosystems. Here we describe atomic force microscope (AFM) application to the understanding of DNA release dynamics from bioreducible polycation-based nanosystems. The two nanosystems are polyplex nanoparticles and layer-by-layer (LbL) films.
Layer-by-layer film engineering for sequential gene delivery
Publisher: Springer New York
Date: 2019
DOI: 10.1007/978-1-4939-9092-4_11
Abstract: Layer-by-layer (LbL) films are assembled with poly(amido amine)s (PAAs), a type of polycations containing bioreducible disulfide bond, and DNA plasmids to enable LbL film degradation in physiologic conditions by reacting with glutathione or redox-active membrane proteins. The interior layer structure of the LbL films during assembly and disassembly is studied by atomic force microscopy (AFM), ellipsometry, dynamic light scattering (DLS), and fluorescence spectroscopy. Insertion of barrier layers in bioreducible LbL films is necessary to stabilize the interior layer structure and slow down the film degradation rate to achieve sequential gene delivery. Localized gene delivery from the LbL films is demonstrated using human embryonic kidney 293 (HEK 293) cells.
Liquid Metal Interface for Two-Precursor Autogenous Deposition of Metal Telluride–Tellurium Networks
Publisher: American Chemical Society (ACS)
Date: 27-09-2023
Measurement of gold nanofilm dose enhancement using unlaminated radiochromic film
Publisher: Wiley
Date: 21-09-2015
DOI: 10.1118/1.4931054
Abstract: Bombarding high-Z material with x-ray radiation releases Auger electrons and Coster-Kronig electrons, along with deeper penetrating fluorescent x-rays and photoelectrons. The Auger and Coster-Kronig electron penetration distance is on the order of nanometers to micrometers in water or tissue, creating a large dose enhancement accompanied by a RBE greater than 1 at the cellular level. The authors' aim is to measure the gold nanofilm dose enhancement factor (DEF) at the cellular level with unlaminated radiochromic film via primary 50 kVp tungsten x-ray spectrum interaction, similar to an electronic brachytherapy spectrum. Unlaminated Gafchromic(®) EBT2 film and Monte Carlo modeling were combined to derive DEF models. Gold film of thickness 23.1 ± 4.3 nm and surface roughness of 1.2 ± 0.2 nm was placed in contact with unlaminated radiochromic film in a downstream orientation and exposed to a 50 kVp tungsten bremsstrahlung, mean energy 19.2 keV. Film response correction factors were derived by Monte Carlo modeling of electron energy deposition in the film's active layer, and by measuring film energy dependence from 4.5 keV to 50 kVp. The measured DEF within a 13.6 μm thick water layer was 0.29 with a mean dose of 94 ± 9.4 cGy from Au emissions and 324 ± 32.4 cGy from the 50 kVp primary beam. Monte Carlo derived correction factors allowed determination of Au contributed dose in shallower depths at 0.25 μm intervals. Maximum DEF of 18.31 was found in the first 0.25 μm water depth. Dose enhancement from Au nanofilm can be measured at the cellular level using unlaminated radiochromic film. Complementing the measured dose value with Monte Carlo calculations allows estimation of dose enhancement at depth increments within the cellular range.
Self-assembly of octadecyltrichlorosilane monolayers on silicon-based substrates by chemical vapor deposition
Publisher: Elsevier BV
Date: 12-2006
AFM study of templated growth of cadmium sulfide nanoparticles using pure and mixed arachidate films
Publisher: Elsevier BV
Date: 2000
Liquid-Metal Solvents for Designing Hierarchical Nanoporous Metals at Low Temperatures
Publisher: American Chemical Society (ACS)
Date: 17-08-2023
Colloidal Perspective on Targeted Drug Delivery to the Central Nervous System
Publisher: American Chemical Society (ACS)
Date: 24-02-2023
Proteome of the porosome complex in human airway epithelia: Interaction with the cystic fibrosis transmembrane conductance regulator (CFTR)
Publisher: Elsevier BV
Date: 2014
3D organization and function of the cell: Golgi budding and vesicle biogenesis to docking at the porosome complex
Publisher: Springer Science and Business Media LLC
Date: 13-04-2012
DOI: 10.1007/S00418-012-0948-X
Abstract: Insights into the three-dimensional (3D) organization and function of intracellular structures at nanometer resolution, holds the key to our understanding of the molecular underpinnings of cellular structure-function. Besides this fundamental understanding of the cell at the molecular level, such insights hold great promise in identifying the disease processes by their altered molecular profiles, and help determine precise therapeutic treatments. To achieve this objective, previous studies have employed electron microscopy (EM) tomography with reasonable success. However, a major hurdle in the use of EM tomography is the tedious procedures involved in fixing, high-pressure freezing, staining, serial sectioning, imaging, and finally compiling the EM images to obtain a 3D profile of sub-cellular structures. In contrast, the resolution limit of EM tomography is several nanometers, as compared to just a single or even sub-nanometer using the atomic force microscope (AFM). Although AFM has been hugely successful in 3D imaging studies at nanometer resolution and in real time involving isolated live cellular and isolated organelles, it has had limited success in similar studies involving 3D imaging at nm resolution of intracellular structure-function in situ. In the current study, using both AFM and EM on aldehyde-fixed and semi-dry mouse pancreatic acinar cells, new insights on a number of intracellular structure-function relationships and interactions were achieved. Golgi complexes, some exhibiting vesicles in the process of budding were observed, and small vesicles were caught in the act of fusing with larger vesicles, possibly representing either secretory vesicle biogenesis or vesicle refilling following discharge, or both. These results demonstrate the power and scope of the combined engagement of EM and AFM imaging of fixed semi-dry cells, capable of providing a wealth of new information on cellular structure-function and interactions.
Surface morphological evolution of ultrathin P4VP films and generation of ordered patterns on graphite
Publisher: Wiley
Date: 10-08-2007
Influence of nano-carrier architecture on in vitro siRNA delivery performance and in vivo biodistribution: Polyplexes vs micelleplexes
Publisher: American Chemical Society (ACS)
Date: 06-04-2011
DOI: 10.1021/NN102540Y
Nanoparticles as seeds for organic crystallization
Publisher: American Chemical Society
Date: 19-09-2008
Lysophosphatidylcholine inhibits membrane-associated SNARE complex disassembly
Publisher: Wiley
Date: 29-07-2012
Toward Precision Deposition of Conductive Charge‐Transfer Complex Crystals Using Nanoelectrochemistry
Publisher: Wiley
Date: 03-2023
Abstract: The lack of understanding for precise synthesis and assembly of nano‐entities remains a major challenge for nanofabrication. Electrocrystallization of a charge‐transfer complex (CTC), tetrathiafulvalene bromide (TTF)Br, is studied on micro/nanoelectrodes for precision deposition of functional materials. The study reveals new insights into the entire CTC electrocrystallization process from the initial nanocluster nucleation to the final elongated crystals with hollow ends grown from the working electrode to the neighboring receiving electrode. On microelectrodes, the number of nucleation sites is reduced to one by lowering the applied overpotential or precursor concentration. Certain current–time transients exhibit significant induction periods prior to stable nucleus growth. The induction regime contains small fluctuating current spikes consistent with stochastic formation of precritical nanoclusters with lifetimes of 0.1–30 s and sizes of 20–160 nm. Electrochemical analyses further reveal rate, size distribution, and formation/dissipation dynamics of the nanoclusters. Crystal growth of (TTF)Br is further studied on triangular nanoelectrode patterns with thickness of 5–500 nm, which shows a mass‐transfer‐controlled process applicable for precision deposition of functional (TTF)Br crystals. This study, for the first time, establishes CTC nanoelectrochemistry as a platform technology for precise deposition of conductive crystal assemblies spanning the source and drain electrode for sensing applications.
Nanoparticles change the ordering pattern of n -carboxylic acids into nanorods on HOPG
Publisher: American Chemical Society (ACS)
Date: 19-10-2010
DOI: 10.1021/NN102184Y
Abstract: This paper describes the formation of organic nanorods induced by monolayer-protected inorganic nanoparticles. Alkanes and alkane derivatives, such as n-carboxylic acids, self-assemble on highly oriented pyrolytic graphite (HOPG) into a persistent molecular packing structure that is dictated by the epitaxial interaction between the carbon chain plane and the HOPG basal plane. Carboxylic acids form 2-D crystalline layers consisting of nanostripe domains whose periodicity is one or two times the molecular chain length. However, when the molecular ordering occurs in the vicinity of a nanoparticle, this persistent HOPG-dominated nanostripe pattern is disrupted, and nanorods attached to the nanoparticles become the dominant structure. In order to understand the underlying mechanism of the nanoparticle-mediated nanorod formation, the effects of film-forming conditions, carboxylic acid chain length, nanoparticle size, and chemical composition of the nanoparticle are examined. It is determined that carboxylic acid nanorods can be induced by nanoparticles of different core materials including CdSe, CdS, and Au, as long as the protecting monolayer allows sufficient dispersion and colloidal stability of the nanoparticles in solution. A carboxylic chain length range amenable to the nanorod formation is identified, as is the relationship between the nanoparticle size and the number of nanorods per nanoparticle. This study contributes to the understanding of seed-mediated crystallization and molecular ordering. Moreover, it defines the parameters governing solution-based formation of hybrid nanostructures and nanopatterns incorporating dual functionality as defined by the inorganic nanoparticle and organic nanorod, respectively.
Self-assembled nanostructures for antireflection optical coatings
Publisher: SPIE
Date: 11-01-2005
DOI: 10.1117/12.577122
Self-Assembly of Photopolymerizable Bolaform Amphiphile Mono- and Multilayers
Publisher: American Chemical Society (ACS)
Date: 12-1993
DOI: 10.1021/LA00036A022
One‐Step Synthesis of Charge‐Transfer Salt Nanosensors on Microelectrode Patterns
Publisher: Wiley
Date: 02-09-2020
Observation of current rectification by the new bimetallic iron(iii ) hydrophobe [FeIII2(LN4O6)] on Au|LB-molecule|Au devices
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8DT03158D
Abstract: A new bimetallic iron hydrophobe, [FeIII2(L N4O6 )] ( 1 ) forms well-defined films used for current–voltage measurements and shows unquestionable molecular rectification.
Layer-by-layer DNA films incorporating highly transfecting bioreducible poly(Amido amine) and polyethylenimine for sequential gene delivery
Publisher: Informa UK Limited
Date: 08-2018
DOI: 10.2147/IJN.S162353
Electrodeposition of partially oxidized tetracyanoplatinate nanowires on seeds and patterns for gas sensing
Publisher: Informa UK Limited
Date: 29-08-2017
Review—Micro/Nanoelectrodes and Their Use in Electrocrystallization: Historical Perspective and Current Trends
Publisher: The Electrochemical Society
Date: 02-2022
Abstract: Crystallization is at the heart of many industrial processes in pharmaceuticals, dyes and pigments, microelectronics, and emerging wearable sensors. This paper reviews nucleation and early-stage crystal growth activated by an electrical pulse at microelectrodes and nanoelectrodes. We review thermodynamic and kinetic theories of electrochemistry developed around microelectrodes. We describe various methods to make microelectrodes and nanoelectrodes. Fundamental understanding is still needed for predicting and controlling nucleation and early-stage crystal growth. Using nanoelectrodes, nucleation and growth kinetics can be studied on one nucleation site at a time. In contrast, on macroelectrodes, nanoparticles are nucleated at random sites and at different times. This gives rise to overlapping growth zones resulting in inhomogeneous particle deposition and growth. The random size and density distributions prevent electrodeposition from being widely adopted as a manufacturing tool for making nanodevices. We describe advances in electrodeposition of metal nanoparticles and organic charge-transfer complexes on micro/nanoelectrodes. We anticipate increased interests in applying electrochemistry for making nanodevices particularly nanosensors and nanosensor arrays. These electrochemically fabricated nanosensor arrays will in turn fulfill the promise of nanoelectrodes as the most advanced analytical tools for medical diagnostics, environmental monitoring, and renewable energy.
Layer-by-layer films with bioreducible and nonbioreducible polycations for sequential DNA release
Publisher: American Chemical Society (ACS)
Date: 31-10-2014
DOI: 10.1021/BM5010433
Abstract: Layer-by-layer (LbL) films containing cationic polyelectrolytes and anionic bioactive molecules such as DNA are promising biomaterials for controlled and localized gene delivery for a number of biomedical applications including cancer DNA vaccine delivery. Bioreducible LbL films made of disulfide-containing poly(amido amine)s (PAAs) and plasmid DNA can be degraded by redox-active membrane proteins through the thiol-disulfide exchange reaction to release DNA exclusively into the extracellular microenvironment adjacent to the film. In order to better understand the film degradation mechanism and nature of the released species, the bioreducible film degradation is studied by atomic force microscopy, fluorescence, and dynamic light scattering in solutions containing a reducing agent. The PAA/DNA LbL film undergoes fast bulk degradation with micrometer-sized pieces breaking off from the substrate. This bulk degradation behavior is arrested by periodic insertions of a nonbioreducible poly(ethylenimine) (PEI) layer. The LbL films containing PAA/DNA and PEI/DNA bilayers display sequential film disassembly and are capable of continuously releasing DNA nanoparticles over a prolonged time. Insertion of the PEI layer enables the bioreducible LbL films to transfect human embryonic kidney 293 cells. The data conclude that the PEI layer is effective as a barrier layer against interlayer diffusion during LbL film assembly and more importantly during film disassembly. Without the barrier layer, the high mobility of cleaved PAA fragments is responsible for bulk degradation of bioreducible LbL films, which may prevent their ultimate gene-delivery applications. This work establishes a direct link among film internal structure, disassembly mechanism, and transfection efficiency. It provides a simple method to design bioreducible LbL films for sequential and long-time DNA release.
Probing small unilamellar EggPC vesicles on mica surface by atomic force microscopy
Publisher: Elsevier BV
Date: 03-2004
Formation of carboxylic acid nanorods on oleylamide-capped Au nanoparticles
Publisher: American Chemical Society (ACS)
Date: 29-02-2012
DOI: 10.1021/JP212279W
Atomically dispersed Pb ionic sites in PbCdSe quantum dot gels enhance room-temperature NO2 sensing
Publisher: Springer Science and Business Media LLC
Date: 12-08-2021
DOI: 10.1038/S41467-021-25192-4
Abstract: Atmospheric NO 2 is of great concern due to its adverse effects on human health and the environment, motivating research on NO 2 detection and remediation. Existing low-cost room-temperature NO 2 sensors often suffer from low sensitivity at the ppb level or long recovery times, reflecting the trade-off between sensor response and recovery time. Here, we report an atomically dispersed metal ion strategy to address it. We discover that bimetallic PbCdSe quantum dot (QD) gels containing atomically dispersed Pb ionic sites achieve the optimal combination of strong sensor response and fast recovery, leading to a high-performance room-temperature p-type semiconductor NO 2 sensor as characterized by a combination of ultra–low limit of detection, high sensitivity and stability, fast response and recovery. With the help of theoretical calculations, we reveal the high performance of the PbCdSe QD gel arises from the unique tuning effects of Pb ionic sites on NO 2 binding at their neighboring Cd sites.
Engineering photonic nanostructure profiles using nanosphere lithography and reactive-ion etching
Publisher: SPIE
Date: 31-08-2006
DOI: 10.1117/12.679628
Nanoparticle-mediated combination chemotherapy and photodynamic therapy overcomes tumor drug resistance in vitro
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.EJPB.2008.08.017
Abstract: Drug resistance limits the success of many anticancer drugs. Reduced accumulation of the drug at its intracellular site of action because of overexpression of efflux transporters such as P-glycoprotein (P-gp) is a major mechanism of drug resistance. In this study, we investigated whether photodynamic therapy (PDT) using methylene blue, also a P-gp inhibitor, can be used to enhance doxorubicin-induced cytotoxicity in drug-resistant tumor cells. Aerosol OT (AOT)-alginate nanoparticles were used as a carrier for the simultaneous cellular delivery of doxorubicin and methylene blue. Methylene blue was photoactivated using light of 665 nm wavelength. Induction of apoptosis and necrosis following treatment with combination chemotherapy and PDT was investigated in drug-resistant NCI/ADR-RES cells using flow cytometry and fluorescence microscopy. Effect of encapsulation in nanoparticles on the intracellular accumulation of doxorubicin and methylene blue was investigated qualitatively using fluorescence microscopy and was quantitated using HPLC. Encapsulation in AOT-alginate nanoparticles significantly enhanced the cytotoxicity of combination therapy in resistant tumor cells. Nanoparticle-mediated combination therapy resulted in a significant induction of both apoptosis and necrosis. Improvement in cytotoxicity could be correlated with enhanced intracellular and nuclear delivery of the two drugs. Further, nanoparticle-mediated combination therapy resulted in significantly elevated reactive oxygen species (ROS) production compared to single drug treatment. In conclusion, nanoparticle-mediated combination chemotherapy and PDT using doxorubicin and methylene blue was able to overcome resistance mechanisms and resulted in improved cytotoxicity in drug-resistant tumor cells.
A Mass Transfer-Based Method for Controlled Electrosynthesis and Organization of Tetrathiafulvalene Bromide Micro/Nanowires
Publisher: The Electrochemical Society
Date: 2019
DOI: 10.1149/2.1001902JES
Self-assembled molecular patterns of fatty acid on graphite in the presence of metal ions
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B604213A
Direct force measurement of comb silicone surfactants in alcoholic media by atomic force microscopy
Publisher: Elsevier BV
Date: 10-2001
Liposome-Micelle-Hybrid (LMH) Carriers for Controlled Co-Delivery of 5-FU and Paclitaxel as Chemotherapeutics
Publisher: MDPI AG
Date: 04-07-2023
DOI: 10.3390/PHARMACEUTICS15071886
Abstract: Paclitaxel (PTX) and 5-fluorouracil (5-FU) are clinically relevant chemotherapeutics, but both suffer a range of biopharmaceutical challenges (e.g., either low solubility or permeability and limited controlled release from nanocarriers), which reduces their effectiveness in new medicines. Anticancer drugs have several major limitations, which include non-specificity, wide biological distribution, a short half-life, and systemic toxicity. Here, we investigate the potential of liposome-micelle-hybrid (LMH) carriers (i.e., drug-loaded micelles encapsulated within drug-loaded liposomes) to enhance the co-formulation and delivery of PTX and 5-FU, facilitating new delivery opportunities with enhanced chemotherapeutic performance. We focus on the combination of liposomes and micelles for co-delivery of PTX and 5_FU to investigate increased drug loading, improved solubility, and transport ermeability to enhance chemotherapeutic potential. Furthermore, combination chemotherapy (i.e., containing two or more drugs in a single formulation) may offer improved pharmacological performance. Compared with in idual liposome and micelle formulations, the optimized PTX-5FU-LMH carriers demonstrated increased drug loading and solubility, temperature-sensitive release, enhanced permeability in a Caco-2 cell monolayer model, and cancer cell eradication. LMH has significant potential for cancer drug delivery and as a next-generation chemotherapeutic.
Corrigendum to “Gold nanoparticle conjugated Rad6 inhibitor induces cell death in triple negative breast cancer cells by inducing mitochondrial dysfunction and PARP-1 hyperactivation: Synthesis and characterization” [Nanomedicine 12 (3) (2016), 745-757](S1549963415002002)(10.1016/j.nano.2015.10.010)
Publisher: Elsevier BV
Date: 06-2019
Electrocrystallization of tetrathiafulvalene charge-transfer salt nanorods on gold nanoparticle seeds
Publisher: American Chemical Society (ACS)
Date: 06-08-2014
DOI: 10.1021/JP505718Q
Effect of chain lengths of PEO-PPO-PEO on small unilamellar liposome morphology and stability: An AFM investigation
Publisher: Elsevier BV
Date: 05-2005
DOI: 10.1016/J.JCIS.2004.11.042
Abstract: The morphology and stability of small unilamellar egg yolk phosphatidylcholine (EggPC) liposomes modified with the Pluronic copolymer (poly (oxyethylene)-poly (oxypropylene)-poly (oxyethylene) (PEO-PPO-PEO)) with different compositions on mica surface have been investigated using atomic force microscopy. Morphology studies reveal significant morphological changes of liposomes upon incorporating the Pluronic copolymer. Bilayers are observed for Pluronic with small hydrophilic (PEO) chain lengths such as L81 [(PEO)2(PPO)40(PEO)2] and L121 [(PEO)4(PPO)60(PEO)4] bilayer and vesicle coexistence is observed for P85 [(PEO)26(PPO)39.5(PEO)26] and F87 [(PEO)61.1(PPO)39.7(PEO)61.1] and stable vesicles are observed for F88 [(PEO)103.5(PPO)39.2(PEO)103.5], F127 [(PEO)100(PPO)65(PEO)100], and F108 [(PEO)132.6(PPO)50.3(PEO)132.6]. The micromechanical properties of Pluronic-modified EggPC vesicles were studied by analyzing AFM approaching force curve. The bending modulus (k(c)) of the Pluronic-modified EggPC vesicles increased several-fold compared with that of the pure EggPC vesicles. The significant difference is due to the enhanced rigidity of the EggPC vesicles as a result of the incorporation of PPO molecules and PEO chains. Based on the analysis of onset point by AFM and diameters of vesicles by light scattering, it was concluded that the favorable model to describe the polymer-bilayer interaction is the membrane-spanning model.
Human Platelet Vesicles Exhibit Distinct Size and Proteome
Publisher: American Chemical Society (ACS)
Date: 09-06-2017
Nanoscale Visualization of Crystal Habit Modification by Atomic Force Microscopy
Publisher: American Chemical Society (ACS)
Date: 03-1997
DOI: 10.1021/CM960470L
Electrospun polyvinyl alcohol-collagen-hydroxyapatite nanofibers: A biomimetic extracellular matrix for osteoblastic cells
Publisher: IOP Publishing
Date: 28-02-2012
DOI: 10.1088/0957-4484/23/11/115101
Abstract: The failure of prosthesis after total joint replacement is due to the lack of early implant osseointegration. In this study polyvinyl alcohol-collagen-hydroxyapatite (PVA-Col-HA) electrospun nanofibrous meshes were fabricated as a biomimetic bone-like extracellular matrix for the modification of orthopedic prosthetic surfaces. In order to reinforce the PVA nanofibers, HA nanorods and Type I collagen were incorporated into the nanofibers. We investigated the morphology, biodegradability, mechanical properties and biocompatibility of the prepared nanofibers. Our results showed these inorganic-organic blended nanofibers to be degradable in vitro. The encapsulated nano-HA and collagen interacted with the PVA content, reinforcing the hydrolytic resistance and mechanical properties of nanofibers that provided longer lasting stability. The encapsulated nano-HA and collagen also enhanced the adhesion and proliferation of murine bone cells (MC3T3) in vitro. We propose the PVA-Col-HA nanofibers might be promising modifying materials on implant surfaces for orthopedic applications.
Aquaporin-assisted and ER-mediated mitochondrial fission: A hypothesis
Publisher: Elsevier BV
Date: 04-2013
Neuroanatomical Tract Tracers: Not Just for Neural Tracing Anymore
Publisher: American Chemical Society (ACS)
Date: 24-03-2023
Synthesis of Copper Sulfide Nanorod Arrays on Molecular Templates
Publisher: American Chemical Society (ACS)
Date: 15-01-2004
DOI: 10.1021/NL034966V
Recognition of Salmonella typhimurium by immobilized phage P22 monolayers
Publisher: Elsevier BV
Date: 04-2008
Influence of TAT-peptide polymerization on properties and transfection activity of TAT/DNA polyplexes
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.JCONREL.2004.09.018
Abstract: Use of bioactive cationic peptides as gene carriers is limited by instability of their DNA complexes in vivo and by the loss of their biological activity due to undesired interactions of their bioactive parts with the DNA. To overcome the two major limitations, biodegradable high-molecular-weight form of TAT peptide (POLYTAT) sensitive to cellular redox-potential gradients was synthesized in this study by oxidative polycondensation. Physicochemical and transfection properties of DNA polyplexes based on POLYTAT were investigated and compared with polyplexes based on TAT polymer prepared by in situ template-assisted polymerization. Physicochemical properties of TAT-based polyplexes were affected by the molecular weight and method of polymerization of the TAT peptide. All TAT-based DNA polyplexes exhibited reduced cytotoxicity when compared with control polyethylenimine (PEI) polyplexes. Polyplexes based on both high-molecular-weight TAT polypeptides exhibited increased transfection efficiency compared to control TAT peptide but lower than that of PEI polyplexes. The evidence shows that transfection activity of TAT-based polyplexes is strongly dependent on the presence of chloroquine and therefore suggests that TAT polyplexes are internalized by an endocytosis. Overall, high-molecular-weight reducible polycations based on bioactive peptides has the potential as versatile carriers of nucleic acids that display low cytotoxicity and can prove to be especially beneficial in cases that require surface presentation of membrane-active or cell-specific targeting peptides.
Induction of necrotic cell death and activation of STING in the tumor microenvironment via cationic silica nanoparticles leading to enhanced antitumor immunity
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR01376D
Abstract: Potent antitumor immunity is induced by intratumoral injection of cytotoxic silica nanoparticles complexed with a STING agonist.
Assembly of surface-independent polyphenol/liquid gallium composite nanocoatings
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2NR02559K
Abstract: A versatile strategy to fabricate surface-independent nanocoatings with entrapped liquid metal nanoparticles has been demonstrated, leveraging from the self-assembly and chelation ability of natural polyphenols.
Direct study of C12 E5 aggregation on mica by atomic force microscopy imaging and force measurements
Publisher: American Chemical Society (ACS)
Date: 11-07-2000
DOI: 10.1021/LA000103V
Nanoconjugate-bound adenosine A1 receptor antagonist enhances recovery of breathing following acute cervical spinal cord injury
Publisher: Elsevier BV
Date: 06-2017
DOI: 10.1016/J.EXPNEUROL.2017.02.013
Abstract: Respiratory complications in patients with spinal cord injury (SCI) are common and can have a negative impact on the quality of patients' lives. Previously, we found that intradiaphragmatic administration of the nanoconjugate-bound A
Impact of Minor Alloy Components on the Electrocapillarity and Electrochemistry of Liquid Metal Fractals
Publisher: Wiley
Date: 19-05-2023
Abstract: Exploring and controlling surface tension‐driven phenomena in liquid metals may lead to unprecedented possibilities for next‐generation microfluidics, electronics, catalysis, and materials synthesis. In pursuit of these goals, the impact of minor constituents within liquid alloys is largely overlooked. Herein, it is showed that the presence of a fraction of solute metals such as tin, bismuth, and zinc in liquid gallium can significantly influence their electrocapillarity and electrochemistry. The instability‐driven fractal formation of liquid alloy droplets is investigated with different solutes and reveals the formation of distinctive non‐branched droplets, unstable fractals, and stable fractal modes under controlled voltage and alkaline solution conditions. In their in idually unique fractal morphology diagrams, different liquid alloys demonstrate significantly shifted voltage thresholds in transition between the three fractal modes, depending on the choice of the solute metal. Surface tension measurements, cycle voltammetry and surface compositional characterizations provide strong evidence that the minor alloy components drastically alter the surface tension, surface electrochemical oxidation, and oxide dissolution processes that govern the droplet deformation and instability dynamics. The findings that minor components are able to regulate liquid alloys’ surface tensions, surface element distributions and electrochemical activities offer great promises for harnessing the tunability and functionality of liquid metals.
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