ORCID Profile
0000-0003-1988-0725
Current Organisations
Flinders University
,
University of Adelaide
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Publisher: Wiley
Date: 03-10-2022
Abstract: An ever‐present risk of medical device associated infection has driven a significant body of research toward development of novel anti‐infective materials. Surfaces bearing sharp nanostructures are an emerging technology to address this concern. The in vitro efficacy of antimicrobial nanostructures has previously been verified using single species cultures, but there remains a paucity of data to address the threat of infections containing more than one species. Polymicrobial infections are a concerning threat because they can complicate treatment, promote drug resistance, and harshen patient prognosis. In the present study, dual‐species cultures are employed to challenge the mechano‐bactericidal properties of nanostructured surfaces. Escherichia coli is used with either Staphylococcus aureus or Enterococcus faecalis due to their clinical relevance in implant associated infection. Despite the presence of two mixed species, a high rate of bactericidal activity is found. Interestingly, in the mixed culture containing Escherichia coli with Enterococcus faecalis , the nanostructured surface triggers a shift in species distribution to favor Enterococcus faecalis . Overall, this study highlights the potential for mechano‐bactericidal surfaces to minimize the burden of infections containing more than one species. It also serves as an enticing foundation for further research into more complex biointerfacial interactions.
Publisher: Elsevier BV
Date: 2021
DOI: 10.2139/SSRN.3762212
Publisher: American Chemical Society (ACS)
Date: 23-11-2022
Abstract: The present study interrogates the interaction of highly efficient antibacterial surfaces containing sharp nanostructures with blood proteins and the subsequent immunological consequences, processes that are of key importance for the fate of every implantable biomaterial. Studies with human serum and plasma pointed to significant differences in the composition of the protein corona that formed on control and nanostructured surfaces. Quantitative analysis using liquid chromatography-mass spectrometry demonstrated that the nanostructured surface attracted more vitronectin and less complement proteins compared to the untreated control. In turn, the protein corona composition modulated the adhesion and cytokine expression by immune cells. Monocytes produced lower amounts of pro-inflammatory cytokines and expressed more anti-inflammatory factors on the nanostructured surface. Studies using an in vivo subcutaneous mouse model showed reduced fibrous capsule thickness which could be a consequence of the attenuated inflammatory response. The results from this work suggest that antibacterial surface modification with sharp spike-like nanostructures may not only lead to the reduction of inflammation but also more favorable foreign body response and enhanced healing, processes that are beneficial for most medical devices implanted in patients.
Publisher: Springer Science and Business Media LLC
Date: 11-2014
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1155/2018/2601945
Abstract: Mesenchymal stromal cell-like populations have been derived from mouse-induced pluripotent stem cells (miPSC-MSC) with the capability for tissue regeneration. In this study, murine iPSC underwent differentiation towards an MSC-like immunophenotype. Stable miPSC-MSC cultures expressed the MSC-associated markers, CD73, CD105, and Sca-1, but lacked expression of the pluripotency marker, SSEA1, and hematopoietic markers, CD34 and CD45. Functionally, miPSC-MSC exhibited the potential for trilineage differentiation into osteoblasts, adipocytes, and chondrocytes and the capacity to suppress the proliferation of mitogen-activated splenocytes. The efficacy of miPSC-MSC was assessed in an acute inflammation model following systemic or local delivery into mice with subcutaneous implants containing heat-inactivated P . gingivalis . Histological analysis revealed less inflammatory cellular infiltrate within the sponges in mice treated with miPSC-MSC cells delivered locally rather than systemically. Assessment of proinflammatory cytokines in mouse spleens found that CXCL1 transcripts and protein were reduced in mice treated with miPSC-MSC. In a periodontitis model, mice subjected to oral inoculation with P . gingivalis revealed less bone tissue destruction and inflammation within the jaws when treated with miPSC-MSC compared to PBS alone. Our results demonstrated that miPSC-MSC derived from iPSC have the capacity to control acute and chronic inflammatory responses associated with the destruction of periodontal tissue. Therefore, miPSC-MSC present a promising novel source of stromal cells which could be used in the treatment of periodontal disease and other inflammatory systemic diseases such as rheumatoid arthritis.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Wiley
Date: 02-02-2015
DOI: 10.1002/WAT2.1064
Abstract: Stormwater biofilters (also called rain gardens, bioretention systems, and bioswales) are used to manage stormwater runoff in urbanized environments. Some benefits of biofilters include flood prevention, stormwater runoff water quality improvement, and wildlife habitat. This technology has been implemented on a larger scale in southeast Australia, but cities and counties in southern California just beginning to construct biofilter systems to manage stormwater runoff. Biofilters tend to be larger in southern California than in southeast Australia. Differences in rainfall patterns likely affect biofilter function. Southern California has much longer periods between rain events than southeast Australia, providing challenges to establishing and maintaining vegetation in biofilters. The use of biofilters for restoring predevelopment flow regimes has been studied in a peri‐urban watershed in southeast Australia, but flow regime restoration is not likely in highly urbanized locations in both Australia and southern California. However, stormwater runoff treatment and harvesting in decentralized biofilters could substantially reduce storm flows and improve water quality in receiving waters while improving urban water supply and extending the life of existing stormwater management infrastructure. WIREs Water 2015, 2:131–146. doi: 10.1002/wat2.1064 This article is categorized under: Water and Life Conservation, Management, and Awareness Engineering Water Sustainable Engineering of Water
Publisher: MDPI AG
Date: 29-03-2022
DOI: 10.3390/NANO12071140
Abstract: Inspired by observations that the natural topography observed on cicada and dragonfly wings may be lethal to bacteria, researchers have sought to reproduce these nanostructures on biomaterials with the goal of reducing implant-associated infections. Titanium and its alloys are widely employed biomaterials with excellent properties but are susceptible to bacterial colonisation. Hydrothermal etching is a simple, cost-effective procedure which fabricates nanoscale protrusions of various dimensions upon titanium, depending on the etching parameters used. We investigated the role of etching time and the choice of cation (sodium and potassium) in the alkaline heat treatment on the topographical, physical, and bactericidal properties of the resulting modified titanium surfaces. Optimal etching times were 4 h for sodium hydroxide (NaOH) and 5 h for potassium hydroxide (KOH). NaOH etching for 4 h produced dense, but somewhat ordered, surface nanofeatures with 75 nanospikes per µm2. In comparison, KOH etching for 5 h resulted sparser but nonetheless disordered surface morphology with only 8 spikes per µm2. The NaOH surface was more effective at eliminating Gram-negative pathogens, while the KOH surface was more effective against the Gram-positive strains. These findings may guide further research and development of bactericidal titanium surfaces which are optimised for the predominant pathogens associated with the intended application.
Publisher: American Chemical Society (ACS)
Date: 25-08-2020
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: Public Library of Science (PLoS)
Date: 24-06-2014
Publisher: Palgrave Macmillan UK
Date: 2015
Publisher: MDPI AG
Date: 08-09-2021
DOI: 10.3390/BIOMEDICINES9091182
Abstract: Biofilm-associated infections are a major cause of impaired wound healing. Despite the broad spectrum of anti-bacterial benefits provided by silver nanoparticles (AgNPs), these materials still cause controversy due to cytotoxicity and a lack of efficacy against mature biofilms. Herein, highly potent ultrasmall AgNPs were combined with a biocompatible hydrogel with integrated synergistic functionalities to facilitate elimination of clinically relevant mature biofilms in-vivo combined with improved wound healing capacity. The delivery platform showed a superior release mechanism, reflected by high biocompatibility, hemocompatibility, and extended antibacterial efficacy. In vivo studies using the S. aureus wound biofilm model showed that the AgNP hydrogel (200 µg/g) was highly effective in eliminating biofilm infection and promoting wound repair compared to the controls, including silver sulfadiazine (Ag SD). Treatment of infected wounds with the AgNP hydrogel resulted in faster wound closure (46% closure compared to 20% for Ag SD) and accelerated wound re-epithelization (60% for AgNP), as well as improved early collagen deposition. The AgNP hydrogel did not show any toxicity to tissue and/or organs. These findings suggest that the developed AgNP hydrogel has the potential to be a safe wound treatment capable of eliminating infection and providing a safe yet effective strategy for the treatment of infected wounds.
Publisher: SAGE Publications
Date: 18-08-2015
Abstract: Induced pluripotent stem cells (iPSCs) are the newest member of a growing list of stem cell populations that hold great potential for use in cell-based treatment approaches in the dental field. This review summarizes the dental tissues that have successfully been utilized to generate iPSC lines, as well as the potential uses of iPSCs for tissue regeneration in different dental applications. While iPSCs display great promise in a number of dental applications, there are safety concerns with these cells that need to be addressed before they can be used in clinical settings. This review outlines some of the apprehensions to the use of iPSCs clinically, and it details approaches that are being employed to ensure the safety and efficacy of these cells. One of the major approaches being investigated is the differentiation of iPSCs prior to use in patients. iPSCs have successfully been differentiated into a wide range of cells and tissue types. This review focuses on 2 differentiation approaches—the differentiation of iPSCs into mesenchymal stem cells and the differentiation of iPSCs into osteoprogenitor cells. Both these resulting populations of cells are particularly relevant to the dental field.
Publisher: American Chemical Society (ACS)
Date: 27-01-2021
Publisher: MDPI AG
Date: 29-12-2022
DOI: 10.3390/NANO13010155
Abstract: Amphotericin B is an antifungal drug used for the treatment of invasive fungal infections. However, its clinical use is limited due to its serious side effects, such as renal and cardiovascular toxicity. Furthermore, hotericin B is administered in high doses due to its poor water solubility. Hence, it is necessary to develop an on-demand release strategy for the delivery of hotericin B to reduce cytotoxicity. The present report describes a novel encapsulation of hotericin B into lipase-sensitive polycaprolactone to form a nanocomposite. Nanocomposites were produced by the oil-in-water method and their physicochemical properties such as size, hydrodynamic diameter, drug loading, and zeta potential were determined. The in vitro release of hotericin B was characterized in the presence and absence of lipase. The antifungal activity of the nanocomposites was verified against lipase-secreting Candida albicans, and cytotoxicity was tested against primary human dermal fibroblasts. In the absence of lipase, the release of hotericin B from the nanocomposites was minimal. However, in the presence of lipase, an enzyme that is abundant at infection sites, a fungicidal concentration of hotericin B was released from the nanocomposites. The antifungal activity of the nanocomposites showed an enhanced effect against the lipase-secreting fungus, Candida albicans, in comparison to the free drug at the same concentration. Furthermore, nanoencapsulation significantly reduced hotericin B-related cytotoxicity compared to the free drug. The synthesized nanocomposites can serve as a potent carrier for the responsive delivery of hotericin B in antifungal applications.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier BV
Date: 09-2023
Publisher: Springer Science and Business Media LLC
Date: 07-02-2014
Publisher: American Chemical Society (ACS)
Date: 28-07-2023
Publisher: Springer Science and Business Media LLC
Date: 06-06-2018
DOI: 10.1007/S00784-017-2137-8
Abstract: The aim of this study was evaluate the effect of triclosan on citrullination and carbamylation, two important protein posttranslational modifications associated with inflammatory conditions such as periodontitis and rheumatoid arthritis. A range of triclosan concentrations were incubated in the presence of appropriate substrates used for the generation of either citrullinated or carbamylated proteins. The effect of triclosan on protein citrullination and carbamylation in macrophages was also assessed. Citrullination and carbamylation were both significantly decreased by triclosan at concentrations six times lower than the 0.3% triclosan approved by the FDA to use in mouthwash and toothpaste. When macrophages were exposed to triclosan, carbamylation was significantly deceased (p = 0.01), and while citrullination also decreased, this reduction was not statistically significant (p = 0.06). Triclosan reduced the generation of protein citrullination and carbamylation in vitro. Triclosan may be useful as an adjunct therapy in the management of inflammatory periodontal diseases and help to reduce posttranslational protein modification citrullination and carbamylation) in these tissues.
Publisher: American Chemical Society (ACS)
Date: 10-09-2015
Abstract: Catchment urbanization perturbs the water and sediment budgets of streams, degrades stream health and function, and causes a constellation of flow, water quality, and ecological symptoms collectively known as the urban stream syndrome. Low-impact development (LID) technologies address the hydrologic symptoms of the urban stream syndrome by mimicking natural flow paths and restoring a natural water balance. Over annual time scales, the volumes of stormwater that should be infiltrated and harvested can be estimated from a catchment-scale water-balance given local climate conditions and preurban land cover. For all but the wettest regions of the world, a much larger volume of stormwater runoff should be harvested than infiltrated to maintain stream hydrology in a preurban state. Efforts to prevent or reverse hydrologic symptoms associated with the urban stream syndrome will therefore require: (1) selecting the right mix of LID technologies that provide regionally tailored ratios of stormwater harvesting and infiltration (2) integrating these LID technologies into next-generation drainage systems (3) maximizing potential cobenefits including water supply augmentation, flood protection, improved water quality, and urban amenities and (4) long-term hydrologic monitoring to evaluate the efficacy of LID interventions.
Publisher: Wiley
Date: 04-02-2022
Abstract: There is a globally increasing demand for medically implanted devices, partly spurred by an aging population. In parallel, there is a proportionate increase in implant associated infection. Much focus has been directed toward the development of techniques to fabricate nanostructured antimicrobial biomaterials to mitigate infection. The present study investigates the interaction of the fungal pathogen Candida albicans with an antimicrobial surface bearing nanoscale protrusions. C. albicans cells were observed to be affected by cell wall stress, which impeded its ability to switch to a hyphal phenotype. There are significant differences in the expression of C. albicans virulence‐associated genes between the untreated and nanostructured surfaces. To determine whether the observed inhibition of C. albicans would also sensitize it to antifungal drugs, a culture is established for 3 days on the nanostructured surface before being treated with the antifungal drug hotericin B. The drug was able to kill all cells on the nanostructured surface at sub‐clinical concentrations, while remaining ineffective against cultures grown on a smooth control surface. These findings may eventually prove to be impactful in the clinic, as clinicians may be able to reduce antifungal drug dosages and minimize the effects of drug associated toxicity.
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.COLSURFB.2022.112600
Abstract: Medical-grade titanium alloys used for orthopaedic implants are at risk from infections and complications such as wear and tear. We have recently shown that hydrothermally etched (HTE) nanostructures (NS) formed on the Ti6AlV4 alloy surfaces impart enhanced anti-bacterial activity which results in inhibited formation of bacterial biofilm. Although these titanium alloy nanostructures may resist bacterial colonisation, their frictional properties are yet to be understood. Orthopaedic devices are encapsulated by bone and muscle tissue. Contact friction between orthopaedic implant surfaces and these host tissues may trigger inflammation, osteolysis and wear. To address these challenges, we performed simulation of the contact behaviour between a smooth control Ti6Al4V alloy and HTE surfaces against a hardwearing SiO
Publisher: Elsevier BV
Date: 12-2013
Publisher: Wiley
Date: 17-10-2017
DOI: 10.1111/JRE.12486
Publisher: Elsevier BV
Date: 2021
Publisher: Wiley
Date: 26-06-2014
DOI: 10.1111/JRE.12205
Abstract: Implantation of periodontal ligament stem cells is emerging as a potential periodontal regenerative procedure. This systematic review considers the evidence from animal models investigating the use of periodontal ligament stem cells for successful periodontal regeneration. PubMed, Embase, MEDLINE and Google Scholar were searched to December 2013 for quantitative studies examining the outcome of implanting periodontal ligament stem cells into experimental periodontal defects in animals. Inclusion criteria were: implantation of periodontal ligament stem cells into surgically created periodontal defects for periodontal regeneration animal models only source of cells either human or animal and published in English. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From the literature search, 43 studies met the inclusion criteria. A wide variety of surgical defects were created in four species of animal (dog, rat, pig and sheep). Owing to wide variability in defect type, cell source and cell scaffold, no meta-analysis was possible. Outcome measures included new bone, new cementum and new connective tissue formation. In 70.5% of the results, statistically significant improvements of these measures was recorded. These results are notable in that they indicate that irrespective of the defect type and animal model used, periodontal ligament stem cell implantation can be expected to result in a beneficial outcome for periodontal regeneration. It is recommended that there is sufficient evidence from preclinical animal studies to warrant moving to human studies to examine the efficacy, safety, feasibility (autologous vs. allogeneic transplantation) and delivery of periodontal ligament stem cells for periodontal regeneration.
Publisher: Wiley
Date: 23-01-2023
Abstract: Dental caries is a major disease associated with the proliferation of acidogenic bacterial species such as Streptococcus mutans that are part of the commensal microbiota of the mouth. Silver nanoparticles (AgNPs) are attractive antibacterial agents as they target multiple sites in bacteria which reduces antimicrobial resistance. In this study, we synthesised stable, highly positively charged AgNPs capped with branched PEI (BPEI‐AgNPs) and characterized them using UV–vis absorption, transmission electron microscopy (TEM), the size of which were approximately 7.5 nm. The antibacterial activity and anti‐biofilm capacity of BPEI‐AgNPs was investigated against cariogenic bacteria. Our results demonstrated that BPEI‐AgNPs are potent clinical oral antiseptics. The cytotoxicity of the BPEI‐AgNPs was also studied against two mammalian cell lines. The results indicated that BPEI‐AgNPs were non‐cytotoxic and were safer than commercially used dental antiseptics. We conclude that the BPEI‐AgNPs are safe for oral clinical application and are an effective oral antimicrobial agent.
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 12-2010
Publisher: Elsevier BV
Date: 05-2006
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.SEMARTHRIT.2014.04.009
Abstract: Periodontitis is a potential risk factor for rheumatoid arthritis (RA). This systematic review considers the evidence for whether non-surgical treatment of periodontitis in RA patients has any effect on the clinical markers of RA disease activity. MEDLINE/PubMed, CINAHL, DOSS, Embase, Scopus, Web of Knowledge, MedNar, Lilacs and ProQuest Theses and Dissertations were searched till September 2013 for quantitative studies examining the effect of non-surgical periodontal treatment on disease activity of RA. The following were the inclusion criteria: (1) patients diagnosed with both RA and chronic periodontitis, aged 30 years or older (2) no antibiotics in the past 3 months or periodontal treatment in the past 6 months (3) non-surgical periodontal therapy (4) age- and gender-matched control group (5) measures of RA activity and (6) published in English. Five studies met the inclusion criteria. Non-surgical periodontal treatment was associated with significant reductions in erythrocyte sedimentation rate and a trend towards a reduction in TNF-α titres and DAS scores. There was no evidence of an effect on RF, C-reactive protein, anti-cyclic citrullinated protein antibodies and IL-6. Based on clinical and biochemical markers, non-surgical periodontal treatment in in iduals with periodontitis and RA could lead to improvements in markers of disease activity in RA. All studies had low subject numbers with the periods of intervention no longer than 6 months. Larger studies are required to explore the effect of non-surgical periodontal treatment on clinical indicators of RA, using more rigorous biochemical and clinical outcome measures as well as giving consideration to potential confounding factors of co-morbidity.
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.MEHY.2015.03.006
Abstract: The remarkable similarity in inflammatory response and pathology of periodontal disease and rheumatoid arthritis has been recognized for several decades. However, how these two disease may be interrelated has been less clear. During the pathogenesis of rheumatoid arthritis there is a preclinical immunological phase which precedes the clinical manifestation of rheumatoid arthritis. During this phase serum autoantibodies appear many years before the clinical signs and symptoms of rheumatoid arthritis become apparent. To date, the two best studied autoantibodies have been rheumatoid factor and anti-citrullinated protein antibodies (ACPA). Of these the production of ACPA has been considered very important due to their high predictive value in future manifestation of rheumatoid arthritis. Citrullination is a common post-translational modification of proteins based on the enzymatic conversion of arginine into citrulline. Extra-articular citrullination and production of ACPA, as a priming immunological experience, is well documented in many tissues including the inflamed gingival tissues associated with periodontal disease. More recently, carbamylation of proteins has also been implicated in the pathogenesis of rheumatoid arthritis in a manner similar to citrullination. Carbamylation is a post translational modification of proteins by an enzyme-independent modification of lysine residues against which autoantibodies are subsequently induced. In this article we hypothesise that, like citrullination, carbamylation of proteins and associated antibody production during the gingival inflammation associated with gingivitis and periodontitis may play a role in the pathogenesis of rheumatoid arthritis.
Publisher: Elsevier BV
Date: 02-2013
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: Elsevier BV
Date: 03-2023
Publisher: American Chemical Society (ACS)
Date: 29-06-2023
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NA00211A
Abstract: The core-in-cage structure of ultra-small AuNPs can be used to define their functions without compromising their size and surface functionalities.
Publisher: American Chemical Society (ACS)
Date: 28-07-2022
DOI: 10.1021/ACS.NANOLETT.2C02182
Abstract: The ever-increasing rate of medical device implantations is met by a proportionately high burden of implant-associated infections. To mitigate this threat, much research has been directed toward the development of antibacterial surface modifications by various means. One recent approach involves surfaces containing sharp nanostructures capable of killing bacteria upon contact. Herein, we report that the mechanical interaction between
Publisher: Wiley
Date: 03-2015
Abstract: The viability of removing less commonly addressed metals (e.g., Cd, Cu, Ni, and Pb) in a passive cotreatment concept was tested using a microcosm-scale, three-stage batch reactor system in which acid mine drainage from an abandoned adit on Cerro Rico de Potosí and raw municipal wastewater from Potosí, Bolivia, were introduced at a 5:1 ratio. The acid mine drainage had pH 3.58, acidity 1080 mg L as CaCO equivalent, and elevated concentrations of dissolved Al, Fe, Mn, Zn, Cd, Cu, Ni, and Pb, among other metals/metalloids. The municipal wastewater had pH 9.05 and alkalinity 418 mg L as CaCO equivalent, with 5.6 and 38 mg L of nitrate and phosphate, respectively. Previous analyses noted substantial pH increase, phosphate removal, denitrification, and removal of Al, Fe, Mn, and Zn. Prompted by these results, subsequent analyses were conducted for the current study, which noted that dissolved concentrations of Cd, Cu, Ni, and Pb decreased by 78.5, 18.3, 25.5, and 45.9%, respectively. Additionally, concentrations of Ce, Cr, Gd, and La decreased throughout the system. The study revealed the broader applicability of passive cotreatment of acid mine drainage and municipal wastewater, specifically for removing metals that are often difficult to address with conventional passive treatment approaches, such as Cd, Cu, Ni, and Pb. Results could be applicable for treatment alternatives in developing and developed countries where these waste streams occur in close proximity.
Publisher: Springer Science and Business Media LLC
Date: 09-2010
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: BMJ
Date: 11-2013
Publisher: BMJ
Date: 15-04-2014
Publisher: American Chemical Society (ACS)
Date: 22-12-2021
Abstract: Silver-based nano-antibiotics are rapidly developing as promising alternatives to conventional antibiotics. Ideally, to remain potent against a wide range of drug-resistant and anaerobic bacteria, silver-based nano-antibiotics should easily penetrate through the bacterial cell walls and actively release silver ions. In this study, highly monodispersed, ultrasmall (<3 nm), polycationic silver nanoclusters (pAgNCs) are designed and synthesized for the elimination of a range of common Gram-negative and Gram-positive pathogens and their corresponding established and matured biofilms, including those composed of multiple species. The pAgNCs also show greatly enhanced antibacterial efficacy against anaerobic bacteria such as
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NR06591B
Abstract: Hemostatic agents are pivotal for managing clinical and traumatic bleeding during emergency and domestic circumstances.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 24-08-2022
DOI: 10.1097/CORR.0000000000002327
Abstract: A nanostructured titanium surface that promotes antimicrobial activity and osseointegration would provide the opportunity to create medical implants that can prevent orthopaedic infection and improve bone integration. Although nanostructured surfaces can exhibit antimicrobial activity, it is not known whether these surfaces are safe and conducive to osseointegration. Using a sheep animal model, we sought to determine whether the bony integration of medical-grade, titanium, porous-coated implants with a unique nanostructured surface modification (alkaline heat treatment [AHT]) previously shown to kill bacteria was better than that for a clinically accepted control surface of porous-coated titanium covered with hydroxyapatite (PCHA) after 12 weeks in vivo. The null hypothesis was that there would be no difference between implants with respect to the primary outcomes: interfacial shear strength and percent intersection surface (the percentage of implant surface with bone contact, as defined by a micro-CT protocol), and the secondary outcomes: stiffness, peak load, energy to failure, and micro-CT (bone volume/total volume [BV/TV], trabecular thickness [Tb.Th], and trabecular number [Tb.N]) and histomorphometric (bone-implant contact [BIC]) parameters. Implants of each material (alkaline heat-treated and hydroxyapatite-coated titanium) were surgically inserted into femoral and tibial metaphyseal cancellous bone (16 per implant type interference fit) and in tibial cortices at three diaphyseal locations (24 per implant type line-to-line fit) in eight skeletally mature sheep. At 12 weeks postoperatively, bones were excised to assess osseointegration of AHT and PCHA implants via biomechanical push-through tests, micro-CT, and histomorphometry. Bone composition and remodeling patterns in adult sheep are similar to that of humans, and this model enables comparison of implants with ex vivo outcomes that are not permissible with humans. Comparisons of primary and secondary outcomes were undertaken with linear mixed-effects models that were developed for the cortical and cancellous groups separately and that included a random effect of animals, covariates to adjust for preoperative bodyweight, and implant location (left/right limb, femoral/tibial cancellous, cortical diaphyseal region, and medial/lateral cortex) as appropriate. Significance was set at an alpha of 0.05. The estimated marginal mean interfacial shear strength for cancellous bone, adjusted for covariates, was 1.6 MPa greater for AHT implants (9.3 MPa) than for PCHA implants (7.7 MPa) (95% CI 0.5 to 2.8 p = 0.006). Similarly, the estimated marginal mean interfacial shear strength for cortical bone, adjusted for covariates, was 6.6 MPa greater for AHT implants (25.5 MPa) than for PCHA implants (18.9 MPa) (95% CI 5.0 to 8.1 p 0.001). No difference in the implant-bone percent intersection surface was detected for cancellous sites (cancellous AHT 55.1% and PCHA 58.7% adjusted difference of estimated marginal mean -3.6% [95% CI -8.1% to 0.9%] p = 0.11). In cortical bone, the estimated marginal mean percent intersection surface at the medial site, adjusted for covariates, was 11.8% higher for AHT implants (58.1%) than for PCHA (46.2% [95% CI 7.1% to 16.6%] p 0.001) and was not different at the lateral site (AHT 75.8% and PCHA 74.9% adjusted difference of estimated marginal mean 0.9% [95% CI -3.8% to 5.7%] p = 0.70). These data suggest there is stronger integration of bone on the AHT surface than on the PCHA surface at 12 weeks postimplantation in this sheep model. Given that the AHT implants formed a more robust interface with cortical and cancellous bone than the PCHA implants, a clinical noninferiority study using hip stems with identical geometries can now be performed to compare the same surfaces used in this study. The results of this preclinical study provide an ethical baseline to proceed with such a clinical study given the potential of the alkaline heat-treated surface to reduce periprosthetic joint infection and enhance implant osseointegration.
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.WATRES.2010.10.026
Abstract: A laboratory-scale, four-stage continuous flow reactor system was constructed to test the viability of high-strength acid mine drainage (AMD) and municipal wastewater (MWW) passive co-treatment. The synthetic AMD had pH 2.60 and 1860 mg/L acidity as CaCO(3) equivalent with 46, 0.25, 2, 290, 55, 1.2 and 390 mg/L of Al, As, Cd, Fe, Mn, Pb and Zn, respectively. The AMD was introduced to the system at a 1:2 ratio with raw MWW from the City of Norman, Oklahoma USA containing 265 ± 94 mg/L BOD(5), 11.5 ± 5.3 mg/L PO(4)(-3), and 20.8 ± 1.8 mg/L NH(4)(+)-N. During the 135 d experiment, PO(4)(-3) and NH(4)(+)-N were decreased to <0.75 and 7.4 ± 1.8 mg/L, respectively. BOD(5) was generally decreased to below detection limits. Nitrification increased NO(3)(-) to 4.9 ± 3.5 mg/L NO(3)(-)-N, however relatively little denitrification occurred. Results suggest that the nitrogen processing community may require an extended period to mature and reach full efficiency. Overall, results indicate that passive AMD and MWW co-treatment is a viable ecological engineering approach for the developed and developing world that can be optimized and applied to improve water quality with minimal use of fossil fuels and refined materials.
Publisher: American Chemical Society (ACS)
Date: 10-08-2021
Abstract: The demand for medical implants globally has increased significantly due to an aging population amongst other reasons. Despite the overall increase in the survivorship of Ti6Al4V implants, implant infection rates are increasing due to factors such as diabetes, obesity, and bacterial resistance to antibiotics. Two commonly found bacteria implicated in implant infections are
Publisher: Wiley
Date: 11-12-2018
DOI: 10.1111/JCPE.12838
Abstract: This study investigated the role of Lactobacillus rhamnosus GG (LGG) on bone loss and local and systemic inflammation in an in vivo mouse model of experimental periodontitis (PD). Experimental PD was induced in mice by oral inoculation with Porphyromonas gingivalis and Fusobacterium nucleatum over a period of 44 days. The probiotic LGG was administered via oral inoculation or oral gavage prior to, and during disease induction. The antimicrobial activity of LGG on the inoculum was also tested. Alveolar bone levels and gingival tissue changes were assessed using in vivo microcomputed tomography and histological analysis. Serum levels of mouse homologues for IL-8 were measured using multiplex assays. Pre-treatment with probiotics either via oral gavage or via oral inoculation significantly reduced bone loss (p < .0001) and gingival inflammation (p < .0001) when compared with PD group. Oral gavage treatment group had significantly less tartrate-resistant acid phosphatase positive cells (p < .02) then PD group. LGG showed no antimicrobial activity against P. gingivalis and F. nucleatum. Lactobacillus rhamnosus GG effectively suppresses bone loss in a mouse model of induced PD irrespective of the mode of administration.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NA00017H
Abstract: The interplay between size and valence state in ∼3 nm silver nanoparticles resulted in the highest antibacterial effect against multi-drug resistant bacteria.
Publisher: Wiley
Date: 2011
DOI: 10.2134/JEQ2010.0176
Abstract: A laboratory-scale, four-stage continuous-flow reactor system was constructed to test the viability of high-strength acid mine drainage (AMD) and municipal wastewater (MWW) passive co-treatment. Synthetic AMD of pH 2.6 and acidity of 1870 mg L(-1) as CaCO3 equivalent containing a mean 46, 0.25, 2.0, 290, 55, 1.2, and 390 mg L(-1) of Al, As, Cd, Fe, Mn, Pb, and Zn, respectively, was added at a 1:2 ratio with raw MWW from the City of Norman, OK, to the system which had a total residence time of 6.6 d. During the 135-d experiment, dissolved Al, As, Cd, Fe, Mn, Pb, and Zn concentrations were consistently decreased by 99.8, 87.8, 97.7, 99.8, 13.9, 87.9, and 73.4%, respectively, pH increased to 6.79, and net acidic influent was converted to net alkaline effluent. At a wasting rate of 0.69% of total influent flow, the system produced sludge with total Al, As, Cd, Cr, Cu, Fe, Pb, and Zn concentrations at least an order of magnitude greater than the influent mix, which presents a metal reclamation opportunity. Results indicate that AMD and MWW passive co-treatment is a viable approach to use wastes as resources to improve water quality with minimal use of fossil fuels and refined materials.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2017
DOI: 10.1097/CJI.0000000000000149
Abstract: Interleukin-2 (IL-2), initially used in 1986, can induce clinical regression—complete responses (CR) and partial responses (PR) of metastatic malignant melanoma. IL-2 has been used alone or in combination, and in different dosage schedules, as an immunotherapeutic agent for melanoma treatment. This meta-analysis aimed to document and evaluate the spectrum of reported clinical response rates from the combined experience of almost 30 years of IL-2 clinical usage. Clinical trials using IL-2 for metastatic melanoma therapy that reported: dosage, combinations, study details, definitions and clinical CR, PR, and overall response (OR) rates were included. A meta-analysis was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. In total, 34 studies met inclusion criteria, with 41 separate treatment arms. For all IL-2 treatment modalities collectively, the CR rate was 4.0% [95% confidence interval (CI), 2.8–5.3], PR 12.5% (95% CI, 10.1–15.0), and OR 19.7% (95% CI, 15.9–23.5). CR pre-1994 was 2.7% versus 6.1% post-1994. High and intermediate-IL-2 dosage showed no CR difference, while low-dose IL-2 showed a nonstatistical trend toward an increased CR rate. The highest CR rate resulted from IL-2 combined with vaccine at 5.0%. The meta-analysis showed that IL-2 immunotherapy for advanced metastatic melanoma delivered a CR rate of 4% (range, 0–23%) across nearly 30 years of clinical studies, with gradual improvement over time. The significance is that, contrary to popular belief, the data demonstrated that CR rates were similar for intermediate versus high-IL-2 dosing.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1MA00444A
Abstract: 3D printing provides numerous opportunities for designing tissue engineering constructs with intricate porosity, geometry and favourable mechanical properties and has the potential to revolutionize medical treatments.
Publisher: MDPI AG
Date: 19-11-2021
Abstract: The link between the microbiome and cancer has led researchers to search for a potential probe for intracellular targeting of bacteria and cancer. Herein, we developed near infrared-emitting ternary AgInSe/ZnS quantum dots (QDs) for dual bacterial and cancer imaging. Briefly, water-soluble AgInSe/ZnS QDs were synthesized in a commercial kitchen pressure cooker. The as-synthesized QDs exhibited a spherical shape with a particle diameter of 4.5 ± 0.5 nm, and they were brightly fluorescent with a photoluminescence maximum at 705 nm. The QDs showed low toxicity against mouse mammary carcinoma (FM3A-Luc), mouse colon carcinoma (C26), malignant fibrous histiocytoma-like (KM-Luc/GFP) and prostate cancer cells, a greater number of accumulations in Staphylococcus aureus, and good cellular uptake in prostate cancer cells. This work is an excellent step towards using ternary QDs for diagnostic and guided therapy for prostate cancer.
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.SEMARTHRIT.2016.02.008
Abstract: Despite recent advances in the treatment of arthritis with the development of disease-modifying antirheumatic drugs, 30% of patients still fail to respond to treatment. Given the potent anti-inflammatory and immunomodulatory properties of mesenchymal stem cells (MSC) and their ability to repair damaged cartilage, bone, and tendons, it has been proposed that MSC could be ideal for cell-based treatment of arthritis. This systematic review investigates evidence from studies on the therapeutic efficacy of MSC in rodent models of arthritis. PubMed, Embase, MEDLINE, and Wed of Science were searched to June 2015 for quantitative studies examining the outcome of treating animal models of arthritis with MSC. Inclusion criteria were as follows: administration of mesenchymal stem as a treatment approach for arthritis animal models only and published in English. We followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The literature search identified 30 studies which met the inclusion criteria. A range of MSC populations were assessed in various rodent models of arthritis. Of these, 19 demonstrated positive outcomes while 11 studies failed to demonstrate positive effects. Owing to the extensive variation in the experimental design, cells investigated and the outcome measures described in the manuscripts, no meta-analysis was possible. Furthermore, the numerical values for the primary outcome measure of clinical paw score were frequently not published in the manuscripts analyzed, as they were only illustrated in graphical form. Numerous studies have investigated the utility of a range of MSC populations in the treatment of experimental arthritis. The results obtained from these studies have been highly inconsistent, with multiple studies identifying a statistically significant improvement in arthritis scores after treatment with MSC, while other studies identified a statistically significant deterioration in arthritis scores and thirdly some studies showed no effect. Further studies using standardized protocols and outcome measures are needed to determine fully the potential of MSC populations in the treatment of experimental arthritis.
Publisher: American Chemical Society (ACS)
Date: 14-10-2022
DOI: 10.1021/ACSBIOMATERIALS.2C00540
Abstract: Titanium and its alloys are frequently the biomaterial of choice for dental implant applications. Although titanium dental implants have been utilized for decades, there are yet unresolved issues pertaining to implant failure. Dental implant failure can arise either through wear and fatigue of the implant itself or peri-implant disease and subsequent host inflammation. In the present report, we provide a comprehensive review of titanium and its alloys in the context of dental implant material, and how surface properties influence the rate of bacterial colonization and peri-implant disease. Details are provided on the various periodontal pathogens implicated in peri-implantitis, their adhesive behavior, and how this relationship is governed by the implant surface properties. Issues of osteointegration and immunomodulation are also discussed in relation to titanium dental implants. Some impediments in the commercial translation for a novel titanium-based dental implant from "bench to bedside" are discussed. Numerous in vitro studies on novel materials, processing techniques, and methodologies performed on dental implants have been highlighted. The present report review that comprehensively compares the in vitro , in vivo , and clinical studies of titanium and its alloys for dental implants.
Publisher: Springer Science and Business Media LLC
Date: 15-02-2013
DOI: 10.1038/SREP01287
Publisher: Wiley
Date: 12-08-2019
No related grants have been discovered for Richard Bright.