ORCID Profile
0000-0003-4415-619X
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 10-2022
Publisher: Springer Science and Business Media LLC
Date: 10-08-2018
DOI: 10.1007/S10544-018-0313-5
Abstract: This work focuses on an evaluation of novel composites of porous silicon (pSi) with the biocompatible polymer ε-polycaprolactone (PCL) for drug delivery and tissue engineering applications. The degradation behavior of the composites in terms of their morphology along with the effect of pSi on polymer degradation was monitored. PSi particles loaded with the drug c tothecin (CPT) were physically embedded into PCL films formed from electrospun PCL fiber sheets. PSi/PCL composites revealed a release profile of CPT (monitored via fluorescence spectroscopy) in accordance with the Higuchi release model, with significantly lower burst release percentage compared to pSi microparticles alone. Degradation studies of the composites, using gravimetric analysis, differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM), carried out in phosphate-buffered saline (PBS) under simulated physiological conditions, indicated a modest mass loss (15%) over 5 weeks due to pSi dissolution and minor polymer hydrolysis. DSC results showed that, relative to PCL-only controls, pSi suppressed crystallization of the polymer film during PBS exposure. This suppression affects the evolution of surface morphology during this exposure that, in turn, influences the degradation behavior of the polymer. The implications of the above properties of these composites as a possible therapeutic device are discussed.
Publisher: Springer Science and Business Media LLC
Date: 12-07-2012
Publisher: Frontiers Media SA
Date: 2016
Publisher: Wiley
Date: 26-01-2016
Abstract: Porous silicon microparticles (pSi MPs) functionalized with fluorescent dyes (lissamine and carboxy-5-fluorescein) and intrinsically luminescent pSi MPs were explored as novel fingerprint dusting powders. The versatility of luminescent pSi MPs is demonstrated through time-gated imaging of their long-lived (lifetime>28 μs) near-IR emission, and mass spectrometry analysis of fingerprints dusted with luminescent pSi MPs to provide further information on exogenous small molecules present in latent fingerprints.
Publisher: American Chemical Society (ACS)
Date: 06-07-2018
Abstract: Porous silicon nanoparticles (pSiNP), modified to target dendritic cells (DC), provide an alternate strategy for the delivery of immunosuppressive drugs. Here, we aimed to develop a DC-targeting pSiNP displaying c-type lectin, dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), and CD11c monoclonal antibodies. The in vivo tracking of these fluorescent DC-targeting nanoparticles was assessed in both C57BL/6 mice and common marmosets ( Callithrix jacchus) by intravenous injection (20 mg/kg). Rapamycin and ovalbumin (OVA)
Publisher: IEEE
Date: 08-2011
Publisher: Wiley
Date: 21-11-2017
Abstract: Flightless I (Flii) is elevated in human chronic wounds and is a negative regulator of wound repair. Decreasing its activity improves healing responses. Flii neutralizing antibodies (FnAbs) decrease Flii activity in vivo and hold significant promise as healing agents. However, to avoid the need for repeated application in a clinical setting and to protect the therapeutic antibody from the hostile environment of the wound, suitable delivery vehicles are required. In this study, the use of porous silicon nanoparticles (pSi NPs) is demonstrated for the controlled release of FnAb to diabetic wounds. We achieve FnAb loading regimens exceeding 250 µg antibody per mg of vehicle. FnAb-loaded pSi NPs increase keratinocyte proliferation and enhance migration in scratch wound assays. Release studies confirm the functionality of the FnAb in terms of Flii binding. Using a streptozotocin-induced model of diabetic wound healing, a significant improvement in healing is observed for mice treated with FnAb-loaded pSi NPs compared to controls, including FnAb alone. FnAb-loaded pSi NPs treated with proteases show intact and functional antibody for up to 7 d post-treatment, suggesting protection of the antibodies from proteolytic degradation in wound fluid. pSi NPs may therefore enable new therapeutic approaches for the treatment of diabetic ulcers.
Publisher: Informa UK Limited
Date: 24-11-2022
Publisher: Elsevier BV
Date: 04-2009
DOI: 10.1016/J.JCIS.2008.12.073
Abstract: In this paper, we describe for the first time the preparation of biodegradable inorganic/organic hybrid materials by grafting poly(L-lactide) (PLLA) from porous silicon (pSi) films and microparticles. To graft a PLLA layer from pSi, tin(II) 2-ethylhexanoate catalysed ring opening polymerisation was performed using pSi surface-bound hydroxyl groups as initiators. Chemical surface characterisation by means of diffuse reflectance infrared spectroscopy, X-ray photoelectron spectroscopy and water contact angle measurements confirmed the presence of the PLLA film. Furthermore, atomic force microscopy demonstrated the formation of PLLA nanobrushes on the pSi surface. We also ascertained by interferometric reflectance spectroscopy that the PLLA layer successfully slowed down the corrosion of the porous silicon layer in aqueous medium. Finally, thermal gravimetric analysis showed weight loss transitions that closely resemble the expected decomposition peak for low molecular weight PLLA. We believe that biodegradable hybrid materials like the ones presented here will find uses in tissue engineering and drug delivery, for ex le in applications where complex degradation profiles are required that cannot be achieved with one type of material alone.
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.810647
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TB00397K
Abstract: Infliximab antibodies released from porous silicon microparticles can sequester the proinflammatory cytokine, tumor necrosis factor-α (TNF-α), which is elevated in uveitis and non-healing chronic wounds.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.EXER.2015.08.007
Abstract: Dysfunction of corneal epithelial stem cells can result in painful and blinding disease of the ocular surface. In such cases, treatment may involve transfer of growth factor and normal adult stem cells to the ocular surface. Our purpose was to develop an implantable scaffold for the delivery of drugs and cells to the ocular surface. We examined the potential of novel composite biomaterials fabricated from electrospun polycaprolactone (PCL) fibres into which nanostructured porous silicon (pSi) microparticles of varying sizes (150-250 μm or <40 μm) had been pressed. The PCL fabric provided a flexible support for mammalian cells, whereas the embedded pSi provided a substantial surface area for efficient delivery of adsorbed drugs and growth factors. Measurements of tensile strength of these composites revealed that the pSi did not strongly influence the mechanical properties of the polymer microfiber component for the Si loadings evaluated. Human lens epithelial cells (SRA01/04) attached to the composite materials, and exhibited enhanced attachment and growth when the materials were coated with foetal bovine serum. To examine the ability of the materials to deliver a small-drug payload, pSi microparticles were loaded with fluorescein diacetate prior to cell attachment. After 6 hours (h), cells exhibited intracellular fluorescence, indicative of transfer of the fluorescein diacetate into viable cells and its subsequent enzymatic conversion to fluorescein. To investigate loading of large-molecule biologics, murine BALB/c 3T3 cells, responsive to epidermal growth factor, insulin and transferrin, were seeded on composite materials. The cells showed significantly more proliferation at 48 h when seeded on composites loaded with these biologics, than on unloaded composites. No cell proliferation was observed on PCL alone, indicating the biologics had loaded into the pSi microparticles. Drug release, measured by ELISA for insulin, indicated a burst followed by a slower, continuous release over six days. When implanted under the rat conjunctiva, the most promising composite material did not cause significant neovascularization but did elicit a macrophage and mild foreign body response. These novel pressed pSi-PCL materials have potential for delivery of both small and large drugs that can be released in active form, and can support the growth of mammalian cells.
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.
Publisher: American Chemical Society (ACS)
Date: 23-05-2011
DOI: 10.1021/LA200551G
Abstract: In this report, we employ surface-initiated atom transfer radical polymerization (SI-ATRP) to graft a thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAM), of controlled thickness from porous silicon (pSi) films to produce a stimulus-responsive inorganic-organic composite material. The optical properties of this material are studied using interferometric reflectance spectroscopy (IRS) above and below the lower critical solution temperature (LCST) of the PNIPAM graft polymer with regard to variation of pore sizes and thickness of the pSi layer (using discrete s les and pSi gradients) and also the thickness of the PNIPAM coatings. Our investigations of the composite's thermal switching properties show that pore size, pSi layer thickness, and PNIPAM coating thickness critically influence the material's thermoresponsiveness. This composite material has considerable potential for a range of applications including temperature sensors and feedback controlled drug release. Indeed, we demonstrate that modulation of the temperature around the LCST significantly alters the rate of release of the fluorescent anticancer drug c tothecin from the pSi-PNIPAM composite films.
Publisher: Informa UK Limited
Date: 18-12-2019
Publisher: Springer Science and Business Media LLC
Date: 30-08-2017
DOI: 10.1038/S41598-017-10793-1
Abstract: Dysfunction of limbal stem cells or their niche can result in painful, potentially sight-threatening ocular surface disease. We examined the utility of surface-modified porous-silicon (pSi) membranes as a scaffold for the transfer of oral mucosal cells to the eye. Male-origin rat oral mucosal epithelial cells were grown on pSi coated with collagen-IV and vitronectin, and characterised by immunocytochemistry. Scaffolds bearing cells were implanted into normal female rats, close to the limbus, for 8 weeks. Histology, immunohistochemistry and a multiplex nested PCR for sry were performed to detect transplanted cells. Oral mucosal epithelial cells expanded on pSi scaffolds expressed the corneal epithelial cell marker CK3/12. A large percentage of cells were p63 + , indicative of proliferative potential, and a small proportion expressed ABCG2 + , a putative stem cell marker. Cell-bearing scaffolds transferred to the eyes of live rats, were well tolerated, as assessed by endpoint histology. Immunohistochemistry for pan-cytokeratins demonstrated that transplanted epithelial cells were retained on the pSi membranes at 8 weeks post-implant, but were not detectable on the central cornea using PCR for sry . The pSi scaffolds supported and retained transplanted rat oral mucosal epithelial cells in vitro and in vivo and recapitulate some aspects of an artificial stem cell niche.
Publisher: American Chemical Society (ACS)
Date: 10-2012
DOI: 10.1021/ES301948K
Abstract: Land Use Regression (LUR) models have been used increasingly for modeling small-scale spatial variation in air pollution concentrations and estimating in idual exposure for participants of cohort studies. Within the ESCAPE project, concentrations of PM(2.5), PM(2.5) absorbance, PM(10), and PM(coarse) were measured in 20 European study areas at 20 sites per area. GIS-derived predictor variables (e.g., traffic intensity, population, and land-use) were evaluated to model spatial variation of annual average concentrations for each study area. The median model explained variance (R(2)) was 71% for PM(2.5) (range across study areas 35-94%). Model R(2) was higher for PM(2.5) absorbance (median 89%, range 56-97%) and lower for PM(coarse) (median 68%, range 32- 81%). Models included between two and five predictor variables, with various traffic indicators as the most common predictors. Lower R(2) was related to small concentration variability or limited availability of predictor variables, especially traffic intensity. Cross validation R(2) results were on average 8-11% lower than model R(2). Careful selection of monitoring sites, examination of influential observations and skewed variable distributions were essential for developing stable LUR models. The final LUR models are used to estimate air pollution concentrations at the home addresses of participants in the health studies involved in ESCAPE.
Publisher: American Chemical Society (ACS)
Date: 15-02-2016
Abstract: Controlling the release kinetics from a drug carrier is crucial to maintain a drug's therapeutic window. We report the use of biodegradable porous silicon microparticles (pSi MPs) loaded with the anticancer drug c hothecin, followed by a plasma polymer overcoating using a loudspeaker plasma reactor. Homogenous "Teflon-like" coatings were achieved by tumbling the particles by playing AC/DC's song "Thunderstruck". The overcoating resulted in a markedly slower release of the cytotoxic drug, and this effect correlated positively with the plasma polymer coating times, ranging from 2-fold up to more than 100-fold. Ultimately, upon characterizing and verifying pSi MP production, loading, and coating with analytical methods such as time-of-flight secondary ion mass spectrometry, scanning electron microscopy, thermal gravimetry, water contact angle measurements, and fluorescence microscopy, human neuroblastoma cells were challenged with pSi MPs in an in vitro assay, revealing a significant time delay in cell death onset.
Publisher: Elsevier BV
Date: 03-2019
Publisher: SPIE
Date: 28-12-2005
DOI: 10.1117/12.659973
Publisher: American Chemical Society (ACS)
Date: 21-12-2015
DOI: 10.1021/ACS.LANGMUIR.5B03794
Abstract: This paper reports on the fabrication of a pSi-based drug delivery system, functionalized with an initiated chemical vapor deposition (iCVD) polymer film, for the sustainable and temperature-dependent delivery of drugs. The devices were prepared by loading biodegradable porous silicon (pSi) with a fluorescent anticancer drug c tothecin (CPT) and coating the surface with temperature-responsive poly(N-isopropylacrylamide-co-diethylene glycol inyl ether) (pNIPAM-co-DEGDVE) or non-stimulus-responsive poly(aminostyrene) (pAS) via iCVD. CPT released from the uncoated oxidized pSi control with a burst release fashion (∼21 nmol/(cm(2) h)), and this was almost identical at temperatures both above (37 °C) and below (25 °C) the lower critical solution temperature (LCST) of the switchable polymer used, pNIPAM-co-DEGDVE (28.5 °C). In comparison, the burst release rate from the pSi-pNIPAM-co-DEGDVE s le was substantially slower at 6.12 and 9.19 nmol/(cm(2) h) at 25 and 37 °C, respectively. The final amount of CPT released over 16 h was 10% higher at 37 °C compared to 25 °C for pSi coated with pNIPAM-co-DEGDVE (46.29% vs 35.67%), indicating that this material can be used to deliver drugs on-demand at elevated temperatures. pSi coated with pAS also displayed sustainable drug delivery profiles, but these were independent of the release temperature. These data show that sustainable and temperature-responsive delivery systems can be produced by functionalization of pSi with iCVD polymer films. Benefits of the iCVD approach include the application of the iCVD coating after drug loading without causing degradation of the drug commonly caused by exposure to factors such as solvents or high temperatures. Importantly, the iCVD process is applicable to a wide array of surfaces as the process is independent of the surface chemistry and pore size of the nanoporous matrix being coated.
Publisher: American Chemical Society (ACS)
Date: 03-07-2012
DOI: 10.1021/MZ300064K
Abstract: A porous silicon-based optical DNA sensor is described herein, which enables rapid DNA detection. The DNA sensor relies on the specificity of the DNA base pairing in conjunction with an interferometric optical signal lification step based on polymer formation within the porous silicon layer to detect the DNA targets in a highly selective fashion. We demonstrate that it is possible to discriminate between DNA strands exhibiting even a single nucleotide mismatch using this sensor.
Publisher: SPIE
Date: 28-12-2006
DOI: 10.1117/12.659972
Publisher: Elsevier BV
Date: 05-2011
Publisher: American Chemical Society (ACS)
Date: 12-2017
Abstract: Continuing our research efforts in developing mesoporous silicon nanoparticle-based biomaterials for cancer therapy, we employed here porous silicon nanoparticles as a nanocarrier to deliver contrast agents to diseased cells. Nanoconfinement of small molecule Gd-chelates (L1-Gd) enhanced the T
Publisher: Bentham Science Publishers Ltd.
Date: 29-04-2020
DOI: 10.2174/1389201020666191203094057
Abstract: Treatment of neurological diseases using systemic and non-surgical techniques presents a significant challenge in medicine. This challenge is chiefly associated with the condensation and coherence of the brain tissue. The coherence structure of the brain is due to the presence of the blood-brain barrier (BBB), which consists of a continuous layer of capillary endothelial cells. The BBB prevents most drugs from entering the brain tissue and is highly selective, permitting only metabolic substances and nutrients to pass through. Although this challenge has caused difficulties for the treatment of neurological diseases, it has opened up a broad research area in the field of drug delivery. Through the utilization of nanoparticles (NPs), nanotechnology can provide the ideal condition for passing through the BBB. NPs with suitable dimensions and optimum hydrophobicity and charge, as well as appropriate functionalization, can accumulate in the brain. Furthermore, NPs can facilitate the targeted delivery of therapeutics into the brain areas involved in Alzheimer’s disease, Parkinson’s disease, stroke, glioma, migraine, and other neurological disorders. This review describes these methods of actively targeting specific areas of the brain.
Publisher: Informa UK Limited
Date: 29-08-2022
Publisher: S. Karger AG
Date: 13-12-2012
DOI: 10.1159/000343018
Abstract: Long-term birth cohort studies are essential to understanding the life course and childhood predictors of allergy and the complex interplay between genes and the environment (including lifestyle and socioeconomic determinants). Over 100 cohorts focusing on asthma and allergy have been initiated in the world over the past 30 years. Since 2004, several research initiatives funded under the EU Framework Program for Research and Technological Development FP6-FP7 have attempted to identify, compare, and evaluate pooling data from existing European birth cohorts (GA sup /sup LEN: Global Allergy and European Network, FP6 ENRIECO: Environmental Health Risks in European Birth Cohorts, FP7 CHICOS: Developing a Child Cohort Research Strategy for Europe, FP7 MeDALL: Mechanisms of the Development of ALLergy, FP7). However, there is a general lack of knowledge about these initiatives and their potentials. The aim of this paper is to review current and past EU-funded projects in order to make a summary of their goals and achievements and to suggest future research needs of these European birth cohort networks.
Publisher: Springer Berlin Heidelberg
Date: 2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA12559F
Abstract: An investigation on the nanophotocathode fabrication using electrochemically anodised pSi NPs for photoelectrochemical water splitting.
Publisher: MDPI AG
Date: 29-03-2018
DOI: 10.3390/NANO8040205
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.ENVINT.2015.04.015
Abstract: An increasing number of epidemiological studies suggest that adverse health effects of air pollution may be related to particulate matter (PM) composition, particularly trace metals. However, we lack comprehensive data on the spatial distribution of these elements. We measured PM2.5 and PM10 in twenty study areas across Europe in three seasonal two-week periods over a year using Harvard impactors and standardized protocols. In each area, we selected street (ST), urban (UB) and regional background (RB) sites (totaling 20) to characterize local spatial variability. Elemental composition was determined by energy-dispersive X-ray fluorescence analysis of all PM2.5 and PM10 filters. We selected a priori eight (Cu, Fe, K, Ni, S, Si, V, Zn) well-detected elements of health interest, which also roughly represented different sources including traffic, industry, ports, and wood burning. PM elemental composition varied greatly across Europe, indicating different regional influences. Average street to urban background ratios ranged from 0.90 (V) to 1.60 (Cu) for PM2.5 and from 0.93 (V) to 2.28 (Cu) for PM10. Our selected PM elements were variably correlated with the main pollutants (PM2.5, PM10, PM2.5 absorbance, NO2 and NOx) across Europe: in general, Cu and Fe in all size fractions were highly correlated (Pearson correlations above 0.75) Si and Zn in the coarse fractions were modestly correlated (between 0.5 and 0.75) and the remaining elements in the various size fractions had lower correlations (around 0.5 or below). This variability in correlation demonstrated the distinctly different spatial distributions of most of the elements. Variability of PM10_Cu and Fe was mostly due to within-study area differences (67% and 64% of overall variance, respectively) versus between-study area and exceeded that of most other traffic-related pollutants, including NO2 and soot, signaling the importance of non-tailpipe (e.g., brake wear) emissions in PM.
Publisher: Wiley
Date: 2017
Publisher: American Vacuum Society
Date: 12-2008
DOI: 10.1116/1.3040158
Abstract: The phase behavior and lateral organization of saturated phosphatidylethanolamine (PE) and phosphatidylcholine (PC) bilayers were investigated using atomic force microscopy (AFM) and force-volume (FV) imaging for both pure and two component mixed layers. The results demonstrated the existence of unexpected segregated domains in pure PE membranes at temperatures well below the transition temperature (Tm) of the component phospholipid. These domains were of low mechanical stability and lacked the capacity for hydrogen bonding between lipid headgroups. Temperature dependent studies for different PC/PE ratios using AFM also demonstrated the mixing of these phospholipid bilayers to exhibit only a single gel to liquid transition temperature. Further work performed using FV imaging and chemically modified probes established that no lipid segregation exists at the PC/PE ratios investigated.
Publisher: Springer Science and Business Media LLC
Date: 19-08-2016
Publisher: Elsevier BV
Date: 12-2021
Publisher: American Chemical Society (ACS)
Date: 21-06-2012
DOI: 10.1021/AM300621K
Abstract: We describe a pH responsive drug delivery system which was fabricated using a novel approach to functionalize biodegradeable porous silicon (pSi) by initiated chemical vapor deposition (iCVD). The assembly involved first loading a model drug (c tothecin, CPT) into the pores of the pSi matrix followed by capping the pores with a thin pH responsive copolymer film of poly(methacrylic acid-co-ethylene dimethacrylate) (p(MAA-co-EDMA)) via iCVD. Release of CPT from uncoated pSi was identical in two buffers at pH 1.8 and pH 7.4. In contrast, the linear release rate of CPT from the pSi matrix with the p(MAA-co-EDMA) coating was dependent on the pH release of CPT was more than four times faster at pH 7.4 (13.1 nmol/(cm(2) h)) than at pH 1.8 (3.0 nmol/(cm(2) h)). The key advantage of this drug delivery approach over existing ones based on pSi is that the iCVD coating can be applied to the pSi matrix after drug loading without degradation of the drug because the process does not expose the drug to harmful solvents or high temperatures and is independent of the surface chemistry and pore size of the nanoporous matrix.
Publisher: American Chemical Society (ACS)
Date: 16-04-2013
DOI: 10.1021/ES305129T
Abstract: Land use regression models (LUR) frequently use leave-one-out-cross-validation (LOOCV) to assess model fit, but recent studies suggested that this may overestimate predictive ability in independent data sets. Our aim was to evaluate LUR models for nitrogen dioxide (NO2) and particulate matter (PM) components exploiting the high correlation between concentrations of PM metrics and NO2. LUR models have been developed for NO2, PM2.5 absorbance, and copper (Cu) in PM10 based on 20 sites in each of the 20 study areas of the ESCAPE project. Models were evaluated with LOOCV and "hold-out evaluation (HEV)" using the correlation of predicted NO2 or PM concentrations with measured NO2 concentrations at the 20 additional NO2 sites in each area. For NO2, PM2.5 absorbance and PM10 Cu, the median LOOCV R(2)s were 0.83, 0.81, and 0.76 whereas the median HEV R(2) were 0.52, 0.44, and 0.40. There was a positive association between the LOOCV R(2) and HEV R(2) for PM2.5 absorbance and PM10 Cu. Our results confirm that the predictive ability of LUR models based on relatively small training sets is overestimated by the LOOCV R(2)s. Nevertheless, in most areas LUR models still explained a substantial fraction of the variation of concentrations measured at independent sites.
Publisher: Future Medicine Ltd
Date: 07-2012
DOI: 10.2217/NNM.11.176
Abstract: Aims: Porous silicon (pSi) and poly(L-lactide) (PLLA) both display good biocompatibility and tunable degradation behavior, suggesting that composites of both materials are suitable candidates as biomaterials for localized drug delivery into the human body. The combination of a pliable and soft polymeric material with a hard inorganic porous material of high drug loading capacity may engender improved control over degradation and drug release profiles and be beneficial for the preparation of advanced drug delivery devices and biodegradable implants or scaffolds. Materials & methods: In this work, three different pSi and PLLA composite formats were prepared. The first format involved grafting PLLA from pSi films via surface-initiated ring-opening polymerization (pSi–PLLA [grafted]). The second format involved spin coating a PLLA solution onto oxidized pSi films (pSi–PLLA [spin-coated]) and the third format consisted of a melt-cast PLLA monolith containing dispersed pSi microparticles (pSi–PLLA [monoliths]). The surface characterization of these composites was performed via infrared spectroscopy, scanning electron microscopy, atomic force microscopy and water contact angle measurements. The composite materials were loaded with a model cytotoxic drug, c tothecin (CPT). Drug release from the composites was monitored via fluorimetry and the release profiles of CPT showed distinct characteristics for each of the composites studied. Results: In some cases, controlled CPT release was observed for more than 5 days. The PLLA spin coat on pSi and the PLLA monolith containing pSi microparticles both released a CPT payload in accordance with the Higuchi and Ritger–Peppas release models. Composite materials were also brought into contact with human lens epithelial cells to determine the extent of cytotoxicity. Conclusion: We observed that all the CPT containing materials were highly efficient at releasing bioactive CPT, based on the cytotoxicity data. Original submitted 16 December 2010 Revised submitted 29 September 2011 Published online 6 March 2012
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/CH15315
Abstract: Porous silicon (pSi) materials are regarded as promising drug delivery vehicles due to their biocompatibility, in vivo degradation, and resorption. We examine pSi films as a platform for the controlled delivery of levothyroxine, as a means to overcome problems with consistent dosage of this drug by oral administration. Oxidized pSi films were modified with 3-(aminopropyl)triethoxysilane (APTES), creating a surface chemistry that increased levothyroxine drug loading capacity by 50 % and sustained drug release under physiological conditions for 14 days. Release kinetics from APTES-functionalized films initially followed a zero-order release profile, which is highly desirable for drug delivery. The loading and release profiles of levothyroxine suggest that the film size required to deliver a therapeutic dose is feasible for further consideration as an implantable delivery system.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.BIOMATERIALS.2017.11.017
Abstract: Dendritic cells (DC) are the most potent antigen-presenting cells and are fundamental for the establishment of transplant tolerance. The Dendritic Cell-Specific Intracellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN CD209) receptor provides a target for dendritic cell therapy. Biodegradable and high-surface area porous silicon (pSi) nanoparticles displaying anti-DC-SIGN antibodies and loaded with the immunosuppressant rapamycin (Sirolimus) serve as a fit-for-purpose platform to target and modify DC. Here, we describe the fabrication of rapamycin-loaded DC-SIGN displaying pSi nanoparticles, the uptake efficiency into DC and the extent of nanoparticle-induced modulation of phenotype and function. DC-SIGN antibody displaying pSi nanoparticles favourably targeted and were phagocytosed by monocyte-derived and myeloid DC in whole human blood in a time- and dose-dependent manner. DC preconditioning with rapamycin-loaded nanoparticles, resulted in a maturation resistant phenotype and significantly suppressed allogeneic T-cell proliferation.
Publisher: Elsevier
Date: 2014
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/309602
Abstract: Monoclonal antibodies (mAbs), available for a range of diseases, including tumours, leukemia, and multiple sclerosis, are emerging as the fastest growing area of therapeutic drug development. The greatest advantage of therapeutic mAbs is their ability to bind with a high degree of specificity to target proteins involved in disease pathophysiology. In response, effector functions are triggered and these ameliorate the disease cascade. As an alternative to this reliance on effector functions, drugs can be conjugated to mAbs. The ability to target compounds to the site of pathology minimises the nonspecific side effects associated with systemic administration. In both instances, optimising the delivery, absorption, and distribution of the mAbs, whilst minimising potential side effects, remain the key hurdles to improved clinical outcomes. Novel delivery strategies are being investigated with more vigour in recent years, and nanoparticles are being identified as suitable vehicles. In conjunction with permitting a controlled release profile, nanoparticles protect the drug from degradation, reducing both the dose and frequency of administration. Moreover, these particles shield the patient from the immune complications associated with high dose mAb infusions or drug cytotoxicity. This review outlines recent advances in nanoparticle technology and how they may be of benefit as therapeutic mAb delivery/targeting vehicles.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TB01409J
Abstract: The ability of a porous silicon microcavity (pSiMC) to act as a luminescence enhancing sensor was confirmed using Eu( iii ) complex labelled streptavidin as a model analyte on a biotin-modified pSiMC.
Publisher: Future Science Ltd
Date: 09-2009
DOI: 10.4155/FMC.09.90
Abstract: Silicon and its oxides are widely used in biomaterials research, tissue engineering and drug delivery. These materials are highly biocompatible, easily surface functionalized, degrade into nontoxic silicic acid and can be processed into various forms such as micro- and nano-particles, monoliths, membranes and micromachined structures. The large surface area of porous forms of silicon and silica (up to 1200 m 2 /g) permits high drug loadings. The degradation kinetics of silicon- and silica-based materials can be tailored by coating or grafting with polymers. Incorporation of polymers also improves control over drug-release kinetics. The use of stimuli-responsive polymers has enabled environmental stimuli-triggered drug release. Simultaneously, silicon microfabrication techniques have facilitated the development of sophisticated implantable drug-delivery microdevices. This paper reviews the synthesis, novel properties and biomedical applications of silicon–polymer hybrid materials with particular emphasis on drug delivery. The biocompatible and bioresorptive properties of mesoporous silica and porous silicon make these materials attractive candidates for use in biomedical applications. The combination of polymers with silicon-based materials has generated a large range of novel hybrid materials tailored to applications in localized and systemic drug delivery.
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B901745C
Abstract: A new and facile method is described to prepare Janus-like nanoporous anodic aluminium oxide (AAO) membranes with distinctly different internal and external surface chemistry.
Publisher: Wiley
Date: 10-2019
DOI: 10.1113/JP278110
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.810101
Publisher: Springer International Publishing
Date: 2016
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.812082
Publisher: Wiley
Date: 16-03-2021
DOI: 10.1113/EP089237
Publisher: Springer International Publishing
Date: 2015
No related grants have been discovered for Steven McInnes.