ORCID Profile
0000-0002-7704-092X
Current Organisation
University of South Australia
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Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TB02482J
Abstract: Silver nanoparticle based coatings preserve the osteogenesis capacity while promoting the adipogenesis of human mesenchymal stem cells through oxidative stress.
Publisher: American Vacuum Society
Date: 05-2020
DOI: 10.1116/6.0000259
Abstract: The stable nitroxide radical TEMPO [(2,2,6,6-Tetramethylpiperidin-1-yl)oxyl] has a multitude of applications in fields ranging from energy storage to biomedical applications and many more. However, to date, the processes of incorporating nitroxide radicals into thin-film coatings are laborious and not cost-effective, which hinders their wider use in many applications. In contrast, the authors have recently demonstrated the facile method of plasma polymerization of TEMPO into thin-film coatings that retain the stable nitroxide radicals. In this work, we are using three types of mass spectroscopic methods (plasma-mass spectrometry, time of flight secondary ion mass spectrometry, and high-performance liquid chromatography-mass spectrometry) and electron spin resonance to track the fate of the TEMPO molecule from monomer flask through the plasma and inside the resulting coatings. The results of this study demonstrate that TEMPO is a versatile monomer that can be used across different plasma reactors and reliably retain the stable nitroxide radical in the resulting thin-film coatings if certain process conditions are observed, namely, higher process pressures and lower powers.
Publisher: Informa UK Limited
Date: 21-12-2015
DOI: 10.1080/08927014.2015.1115977
Abstract: Bacterial colonization of medical devices causes infections and is a significant problem in healthcare. The use of antibacterial coatings is considered as a potential solution to this problem and has attracted a great deal of attention. Using concentration density gradients of immobilized quaternary ammonium compounds it was demonstrated that a specific threshold of surface concentration is required to induce significant bacterial death. It was determined that this threshold was 4.18% NR4(+) bonded nitrogen with a surface potential of + 120.4 mV. Furthermore, it is shown for the first time that adhesion of constituents of the culture medium to the quaternary ammonium modified surface eliminated any cytotoxicity towards eukaryotic cells such as primary human fibroblasts. The implications of this type of surface fouling on the antimicrobial efficacy of surface coatings are also discussed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC00260E
Abstract: We report novel solvent-free and substrate independent, plasma polymerised nanoscale biocompatible polyoxazoline coatings capable of controlling protein and cell adhesion, and significantly reducing biofilm build up.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC08151J
Abstract: Herein, we report a novel and solvent-free technique for the encapsulation of pharmaceuticals that allows achieving controllable release rates.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TB02551F
Abstract: In this study, the antibacterial efficacy of NO-releasing porous silicon nanoparticles (pSiNPs) is reported. NO-releasing pSiNPs were produced via the conjugation of S -nitrosothiol (SNO) and S -nitrosoglutathione (GSNO) donors to the nanoparticle surfaces.
Publisher: Elsevier BV
Date: 2013
Publisher: Wiley
Date: 22-07-2019
Abstract: This report addresses the issue of optimizing extracellular matrix protein density required to support osteogenic lineage differentiation of mesenchymal stem cells (MSCs) by culturing MSCs on surface-bound density gradients of immobilized collagen type I (COL1) and osteopontin (OPN). A chemical surface gradient is prepared by tailoring the surface chemical composition from high hydroxyl groups to aldehyde groups using a diffusion-controlled plasma polymerization technique. Osteogenesis on the gradient surface is determined by immunofluorescence staining against Runx2 as an early marker and by staining of calcium phosphate deposits as a late stage differentiation marker. The Runx2 intensity and calcified area increase with increasing COL1 density up to a critical value corresponding to 124.2 ng cm
Publisher: American Chemical Society (ACS)
Date: 03-2016
Abstract: Infections caused by the bacterial colonization of medical devices are a substantial problem to patients and healthcare. Biopassive polyoxazoline coatings are attracting attention in the biomedical field as one of the potential solutions to this problem. Here, we present an original and swift way to produce plasma-deposited oxazoline-based films for antifouling applications. The films developed via the plasma deposition of 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline have tunable thickness and surface properties. Diverse film chemistries were achieved by tuning and optimizing the deposition conditions. Human-derived fibroblasts were used to confirm the biocompatibility of oxazoline derived coatings. The capacity of the coatings to resist biofilm attachment was studied as a function of deposition power and mode (i.e., continuous wave or pulsed) and precursor flow rates for both 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline. After careful tuning of the deposition parameters films having the capacity to resist biofilm formation by more than 90% were achieved. The substrate-independent and customizable properties of the new generation of plasma deposited oxazoline thin films developed in this work make them attractive candidates for the coating of medical devices and other applications where bacteria surface colonization and biofilm formation is an issue.
Publisher: Wiley
Date: 10-2019
Publisher: Wiley
Date: 08-2019
Publisher: Wiley
Date: 03-02-2020
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.JCIS.2015.06.040
Abstract: Hybrid micro and nanoparticles have become a topic of intense research in recent years. This is due to the special properties of these materials that open new avenues in advanced applications. Herein, we report a novel method for the generation of hybrid particles utilising plasma polymerization. Poly (methyl methacrylate) (PMMA) beads were first coated with a thin allylamine based plasma polymer layer. Gold nanoparticles of engineered size and surface structure were then attached in a controlled manner to the plasma polymer coated beads. To generate uniform chemistry on the outermost surface and to preserve the nanotopography, we deposited a 5-10 nm thin layer of Acpp. We demonstrated that these particles can be utilized in in vivo models to interrogate important biological phenomena. Specifically, we used them in mice to study the inflammatory and foreign body responses to surface nanotopography. The data strongly indicates that surface nanotopography and chemistry can modulate collagen production and the number of adhering immune cells. The method for generating hybrid particles reported here is solvent free and can open new opportunities in fields such as tissue engineering, drug delivery, biosensors, and regenerative medicine.
Publisher: American Vacuum Society
Date: 27-02-2014
DOI: 10.1116/1.4866697
Abstract: Bacterial infections are continuing to pose a significant threat to human health. Coatings with inherent antibacterial properties are becoming increasingly common as an infection preventative measure. The aim of this review is to highlight recent progress in development of “smart” and responsive antibacterial surfaces. The review describes various strategies utilized for generation of such surfaces and the specific stimuli that are used to trigger antibacterial action. It also provides a critical discussion of the advantages and drawbacks of different approaches. The review concludes with a perspective about the future of the field and outlines the challenges and obstacles that need to be overcome in order to make future advances.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TB00901D
Abstract: Nanoscale polyoxazoline coatings generated via a single step plasma deposition process are investigated. The complex functionality of the film can be controlled by varying the deposition conditions. Partial retention of the oxazoline ring facilitates covalent binding of nanoparticles and biomolecules.
Publisher: American Chemical Society (ACS)
Date: 15-03-2013
DOI: 10.1021/BM302003M
Abstract: Antibacterial nanodevices could bring coatings of plastic materials and wound dressings a big step forward if the release of the antibacterial agents could be triggered by the presence of the bacteria themselves. Here, we show that novel hyaluronic acid (HA)-based nanocapsules containing the antimicrobial agent polyhexanide are specifically cleaved in the presence of hyaluronidase, a factor of pathogenicity and invasion for bacteria like Staphylococcus aureus and Escherichia coli. This resulted in an efficient killing of the pathogenic bacteria by the antimicrobial agent. The formation of different polymeric nanocapsules was achieved through a polyaddition reaction in inverse miniemulsion. After the synthesis, the nanocapsules were transferred to an aqueous medium and investigated in terms of size, size distribution, functionality, and morphology using dynamic light scattering, zeta potential measurements and scanning electron microscopy. The enzyme triggered release of a model dye and the antimicrobial polyhexanide was monitored using fluorescence and UV spectroscopy. The stability of the nanocapsules in several biological media was tested and the interaction of nanocapsules with human serum protein was studied using isothermal titration calorimetry. The antibacterial effectiveness is demonstrated by determination of the antibacterial activity and determination of the minimal bactericidal concentration (MBC).
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.NANO.2013.07.002
Abstract: The enzyme-triggered release of the antimicrobial agent octenidine out of poly(l-lactide)-based nanoparticles (PLLA-NPs) and their in vitro antibacterial activities in the presence of gram-positive and gram-negative bacteria are presented. The formation of the nanoparticles was achieved using a combination of the solvent evaporation and the miniemulsion approach. For the stabilization of the polymeric nanoparticles, non-ionic polymers (polyvinylalcohol [PVA], hydroxyethyl starch [HES], human serum albumin [HSA]) were successfully used for enzymatic degradation ionic surfactants such as sodium dodecyl sulfate and cetyltrimethylammonium chloride inhibited the enzymatic degradation. The change in pH, size, size distribution and morphology during the degradation process of PLLA-NPs and the release of the antimicrobial agent was studied. The influence of the different amounts of octenidine and of the different stabilizers on the NPs' stability, size, size distribution, morphology, zeta potential and on the surface group's density is discussed. Fluorescently labeled HES-stabilized PLLA-NPs are immobilized by colloidal electrospinning. The observed data from HPLC measurements show that octenidine is released out of PLLA-NPs which are stabilized with PVA, HES or HSA. In bacteria tests the PLLA nanoparticles showed a greater ability to inhibit the growth of Staphylococcus aureus compared to Escherichia coli. This article discusses the enzyme-triggered release and antibacterial effects of octenidine from poly(l-lactide)-based nanoparticles demonstrating the viability of this approach for potential future antibacterial therapy.
Publisher: American Chemical Society (ACS)
Date: 09-11-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TB00648A
Abstract: Thermo-responsive drug release from diatom biosilica microcapsules is demonstrated for the first time using microcapsules modified with copolymers of oligoethylene glycol methacrylates.
No related grants have been discovered for Alex Cavallaro.