ORCID Profile
0000-0002-9884-4126
Current Organisation
University of South Australia
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Publisher: American Chemical Society (ACS)
Date: 12-09-2013
DOI: 10.1021/MA4013187
Publisher: Wiley
Date: 20-06-2023
Abstract: Rif icin (RFP) is a first‐line drug used to treat a variety of infections, including wound infections but has limitations in its use due to its toxicity. Hence, an urgent need exists for the development of suitable carriers for the delivery of the antibiotic. In this study, a novel approach is introduced for drug administration, employing stimulus‐responsive carriers to achieve an on‐demand strategy. This innovative method aims to minimize the dosage and frequency of drug administration, consequently lowering cytotoxicity levels. We used the lipases‐sensitive polycaprolactone (PCL) to produce nanocomposites loaded with rif icin (PCL−RFP NPs). Nanoparticles were prepared by a single‐step emulsion solvent evaporation method. The size distribution of blank nanoparticles (PCL NPs) and PCL−RFP NPs were 172±30 nm and 229±58 nm, respectively. The liberation of RFP from PCL−RFP NPs was monitored over a period of 72 h in the absence and the presence of lipase was 9.46±0.24 % and 53.3±3.33 %, respectively, indicating responsive behavior. The minimum inhibitory concentration to lipase‐expressing Staphylococcus aureus ( S. aureus ) of PCL−RFP NPs was significantly improved compared to the free drug. Cytotoxicity tests using human dermal fibroblasts showed that the nanocomposites had better biocompatible when compared to the free drug. These findings indicate that the developed nanocomposite carriers have the potential to be promising candidates for delivering antibiotics in the field of biomedicine.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CS60065C
Abstract: This mini-review describes basic features and applications of small molecules and macromolecules containing amidine, and to a lesser extent, guanidine functional groups. The emphasis in this article is on the exploitation of such functionality as species that are capable of reversibly binding carbon dioxide in the presence of water, a process that also commonly involves a hydrophobic-to-hydrophilic transition. The review is not intended to be exhaustive but rather serves to highlight this one particular feature and demonstrate its application in areas ranging from reversible emulsion stabilization, purification and reversible self-assembly of polymeric nanoparticles.
Publisher: Elsevier BV
Date: 03-2023
Publisher: American Chemical Society (ACS)
Date: 28-06-2017
DOI: 10.1021/ACS.LANGMUIR.7B01175
Abstract: Surface wetting on the textured surface is classically explained by the theories of Cassie-Baxter or Wenzel. However, in recent years, an increasing number of complex surface topographies with superhydrophobic properties have been achieved without prediction or simulation using these theories. One ex le is biomimetic surfaces. In many instances, theories were used to explain surface properties found in nature but have not led to or predicted the complex topographies. Although new wetting theories continue to emerge, there is not yet a set of design rules to guide the selection of surface topographies to achieve superhydrophobicity. By grouping known surface topographies into common geometrical descriptions and length scale, this paper suggests a set of surface topography classifications to provide selection guidelines for engineering superhydrophobic surfaces. Two key outcomes emerged from the design analysis: first, categorization of frequently reported surface patterns shows that there exists a set of commonly used descriptions among erse designs second, the degree of hydrophobicity improvement within a class of topography design can be used to predict the limit of improvement in superhydrophobicity for a given material. The presentation of topography descriptors by categories of design and performance may serve as a prologue to an eventually complete set of design guidelines for superhydrophobic performance.
Publisher: American Chemical Society (ACS)
Date: 29-02-2012
DOI: 10.1021/BM2017299
Abstract: Three monomers with 1,3-dicarboxylate functional groups but varying spacer lengths were synthesized via carbon Michael addition using malonate esters and ethylene- (MAETC), butylene- (MABTC), and hexylene (MAHTC) glycol dimethacrylate, respectively. Poly[oligo-(ethylene glycol) methylether methacrylate] (POEGMEMA) was prepared in the presence of a RAFT (reversible addition-fragmentation chain transfer) agent, followed by chain extension with the prepared monomers to generate three different block copolymers (BP-E80, BP-B82, and BP-H79) with similar numbers of repeating units, but various spacer lengths as distinguishing features. Conjugation with platinum drugs created macromolecular platinum drugs resembling carboplatin. The hiphilic natures of these Pt-containing block copolymers led to the formation micelles in solution. The rate of drug release of all micelles was similar, but a noticeable difference was the increasing stability of the micelle against dissociation with increasing spacer length. The platinum conjugated polymer showed high activity against A549, OVCAR3, and SKOV3 cancer cell lines exceeding the activity of carboplatin, but only the micelle based on the longest spacer had IC(50) values as low as cisplatin. Cellular uptake studies identified a better micelle uptake with increasing micelle stability as a possible reason for lower IC(50) values. The clonogenic assay revealed that micelles loaded with platinum drugs, in contrast to low molecular weight carboplatin, have not only better activity within the frame of a 72 h cell viability study, but also display a longer lasting effect by preventing the colony formation A549 for more than 10 days.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4PY01108B
Abstract: Five R-group di-functional dithiobenzoates have been prepared and used in the reversible addition–fragmentation chain transfer polymerization of 2-vinyl-4,4-dimethylazlactone.
Publisher: Elsevier BV
Date: 2015
Publisher: American Chemical Society (ACS)
Date: 17-09-2020
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.COLSURFB.2022.112590
Abstract: Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for the treatment of pain, inflammation and fever. However, most NSAIDs are poorly water soluble, making it difficult to be administered thus high doses are required to reach the intended therapeutic effect, resulting in associated side effects. In this study, ROS-responsive micellar systems based on a block copolymer consisting of methylpropyl thioether (MTPA) and N'N-dimethylacrylamide was developed and loaded with ibuprofen (IBU). Using lipopolysaccharide activated RAW 264.7 macrophage like cells, we demonstrated that IBU was released from the copolymer, specifically in the presence of ROS. Interestingly, IBU encapsulated in ROS-responsive nanoparticles exhibited greater anti-inflammatory potency compared to its free form. The work highlights the potential of the ROS-responsive micellar system developed in this work to be used as carrier of NSAIDs for the treatment of relevant inflammatory conditions.
Publisher: Elsevier BV
Date: 03-2022
Publisher: Wiley
Date: 29-10-2013
DOI: 10.1002/POLA.26397
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC04139A
Abstract: Shaking solutions of tailored (co)polymers in soda water is shown to induce precipitation, nanoparticle formation, or polymer or nanoparticle dissolution.
Publisher: Wiley
Date: 13-08-2023
Abstract: Macrophage polarization is a significant event in the host immune response, which can be modulated by modifying the surface of a biomaterial. Previous studies have demonstrated the modulation of macrophage polarization using different surface features however, none of these studies reflect the effect of surface properties on unstimulated macrophage polarization for a prolonged period. To better understand the impact of surface features, in this work differentiated THP‐1 cells are employed to control macrophage polarization on nano‐rough surfaces for a duration of 7 days. Model nano‐rough substrates are fabricated by immobilizing gold nanoparticles (AuNPs) of predetermined sizes (16, 38, 68 nm) on a 2‐methyl‐2‐oxazoline thin film, followed by tailoring the outermost surface chemistry. All modified surfaces support high levels of cell adhesion and proliferation. Over time, the expression of pro‐inflammatory cytokines decreases, whereas the expression of anti‐inflammatory cytokines increases on all modified surfaces. Similarly, pro‐inflammatory interleukin (IL)‐1β gene expression is downregulated, and anti‐inflammatory IL‐10‐gene expression is upregulated, regardless of the surface roughness. Analysis of cell morphology reveals that the predominant cell type on the modified surfaces exhibits M2 anti‐inflammatory phenotype. Herein, how surface features can modulate macrophage responses over an extended period is highlighted, offering insights for the development of future biomaterial implants.
Publisher: Wiley
Date: 10-2022
Abstract: Ultrasmall cationic silver nanoparticles (AgNPs) have recently emerged as highly potent antimicrobial agents for the treatment of multidrug‐resistant bacteria and their biofilms. However, the clinical application of these cationic AgNPs is h ered by their poor stability and high reactivity in solution, leading to uncontrolled release of toxic silver ions. An ideal platform featuring broad‐spectrum antibacterial activity and high biocompatibility that prevents overexposure to silver ions, is therefore highly desirable. Herein, we explored a biocompatible and biodegradable polymer, poly(lactic‐co‐glycolic) acid (PLGA) as an effective carrier for the recently discovered polycationic silver nanoclusters (pAgNCs). These pAgNCs impregnated PLGA nanocomposites (pAgNCs@PLGA) were developed by water‐in‐oil‐in‐water (W 1 /O/W 2 ) emulsion method and characterized by various analytical techniques. Our experimental results reveal that pAgNCs@PLGA had spherical morphology with an average diameter of ∼188 nm and consists of multiple ultrasmall (∼2 nm) pAgNCs at the polymeric core. The minimum inhibitory concentration of pAgNCs for Staphylococcus aureus and Pseudomonas aeruginosa were found to be 6.9 μg/mL. After impregnation within PLGA, the antimicrobial efficacy of our pAgNCs against Staphylococcus aureus and Pseudomonas aeruginosa remained consistent, while the nanocomposites were biocompatible at the minimum inhibitory concentration (MIC) against both bacteria. The pAgNCs@PLGA nanocomposite developed in this work may present a path forward to bring these highly potent pAgNCs into medical practice.
Publisher: American Chemical Society (ACS)
Date: 05-08-2013
DOI: 10.1021/MA401096R
No related grants have been discovered for Jing Yang Quek.