Dr Cindy Gunawan joined UTS in 2015 as a Chancellor’s Postdoctoral Research Fellow in the ithree Institute (infection, immunity innovation). Dr Gunawan graduated from UNSW Australia as Bachelor of Engineering in Bioprocess Engineering with The University Medal in 2002. Awarded with The International Postgraduate Research Scholarship (Department of Education, Science and Training and UNSW Australia), Dr Gunawan pursued her PhD in Biotechnology, developing a highly efficient biotransformation system for production of pharmaceutical precursor, which was completed in 2006. In 2008-2014, Dr Gunawan joined the Particle and Catalysis research group in the School of Chemical Engineering, UNSW.
Dr Gunawan's expertise is in the fusion of nanomaterials engineering and cellular biology, specializing on the nanoparticle-cell interactions. Dr Gunawan's research seeks to unravel the toxicity origins of antimicrobial nanoparticles on bacteria and in turn, how bacteria develop resistance to the nanoparticles. Through her nano-bio expertise, Dr Gunawan also contributes to the development of smart nanoparticle-based antimicrobials and therapeutics as well as to understand the role of nanoparticles in the pathogenesis of neurodegenerative disorder. These pioneering research have resulted in publications in high ranked journals, including Small, ACS Nano and Biomaterials, as well as being featured in Nature Nanotechnology as one of its Research Highlights.
In 2013, Dr Gunawan’s team discovered the phenomena of bacterial resistance to nanosilver, one of the most developed and commercialised antimicrobial nanoparticles. The work, published in Small, has featured in scientific and public media outlets, including the ARC (http://www.arc.gov.au/news-media/news/resilient-bacteria-adapt-nanosilver) and Science Alert (http://www.sciencealert.com.au/news/20130805-24354.html). The team's 2017 publication in ACS Nano highlights the genuine potential of the current widespread and indiscriminate use of nanosilver to facilitate resistance development and its spread. The findings call for judicial and effectively regulated use of nanosilver (http://www.nanowerk.com/nanotechnology-news/newsid=46282.php).
Can supervise: YES
Gunawan, C, Faiz, MB, Mann, R, Ting, SRS, Sotiriou, GA, Marquis, CP & Amal, R 2020, 'Nanosilver Targets the Bacterial Cell Envelope: The Link with Generation of Reactive Oxygen Radicals', ACS APPLIED MATERIALS & INTERFACES, vol. 12, no. 5, pp. 5557-5568.View/Download from: Publisher's site
Valentin, E, Bottomley, AL, Chilambi, GS, Harry, EJ, Amal, R, Sotiriou, GA, Rice, SA & Gunawan, C 2020, 'Heritable nanosilver resistance in priority pathogen: A unique genetic adaptation and comparison with ionic silver and antibiotics', Nanoscale, vol. 12, no. 4, pp. 2384-2392.View/Download from: Publisher's site
© 2020 The Royal Society of Chemistry. The past decade has seen the incorporation of antimicrobial nanosilver (NAg) into medical devices, and, increasingly, in everyday 'antibacterial' products. With the continued rise of antibiotic resistant bacteria, there are concerns that these priority pathogens will also develop resistance to the extensively commercialized nanoparticle antimicrobials. Herein, this work reports the emergence of stable resistance traits to NAg in the WHO-listed priority pathogen Staphylococcus aureus, which has previously been suggested to have no, or very low, capacity for silver resistance. With no native presence of genetically encoded silver defence mechanisms, the work showed that the bacterium is dependent on mutation of physiologically essential genes, including those involved in nucleotide synthesis and oxidative stress defence. While some mutations were uniquely associated with resistance to NAg, the study also found common mutations that could be protective against both NAg and ionic silver. This is consistent with the observation of NAg/ionic silver cross-resistance. These mutations were detected following withdrawal of the silver exposure, denoting heritable characteristics that allow for spread of the resistance traits even with discontinued silver use. Heritable silver resistance in priority pathogen cautions that these nanoparticle antimicrobials should only be used as needed, to preserve their efficacy for treating infections.
Gunawan, C, Lord, MS, Lovell, E, Wong, RJ, Jung, MS, Oscar, D, Mann, R & Amal, R 2019, 'Oxygen-Vacancy Engineering of Cerium-Oxide Nanoparticles for Antioxidant Activity.', ACS omega, vol. 4, no. 5, pp. 9473-9479.View/Download from: UTS OPUS or Publisher's site
To address an important challenge in the engineering of antioxidant nanoparticles, the present work devised a surface-to-bulk migration of oxygen vacancies in the oxygen radical-scavenging cerium-oxide nanoparticles. The study highlights the significance of surface oxygen vacancies in the intended cellular internalization and, subsequently, the radical scavenging activity of the nanoparticles inside the cells. The findings advise future development of therapeutic antioxidant nanomaterials to also include engineering of the particles for enhanced surface defects not only for the accessibility of their oxygen vacancies but also, equally important, rendering them bioavailable for cellular uptake.
Faiz, MB, Amal, R, Marquis, CP, Harry, EJ, Sotiriou, GA, Rice, SA & Gunawan, C 2018, 'Nanosilver and the microbiological activity of the particulate solids versus the leached soluble silver.', Nanotoxicology, vol. 12, no. 3, pp. 263-273.View/Download from: UTS OPUS or Publisher's site
Nanosilver (Ag NPs) is currently one of the most commercialized antimicrobial nanoparticles with as yet, still unresolved cytotoxicity origins. To date, research efforts have mostly described the antimicrobial contribution from the leaching of soluble silver, while the undissolved solid Ag particulates are often considered as being microbiologically inert, serving only as source of the cytotoxic Ag ions. Here, we show the rapid stimulation of lethal cellular oxidative stress in bacteria by the presence of the undissolved Ag particulates. The cytotoxicity characteristics are distinct from those arising from the leached soluble Ag, the latter being locked in organic complexes. The work also highlights the unique oxidative stress-independent bacterial toxicity of silver salt. Taken together, the findings advocate that future enquiries on the antimicrobial potency and also importantly, the environmental and clinical impact of Ag NPs use, should pay attention to the potential bacterial toxicological responses to the undissolved Ag particulates, rather than just to the leaching of soluble silver. The findings also put into question the common use of silver salt as model material for evaluating bacterial toxicity of Ag NPs.
Kusrini, E, Hashim, F, Gunawan, C, Mann, R, Azmi, WNNWN & Amin, NM 2018, 'Anti-amoebic activity of acyclic and cyclic-samarium complexes on Acanthamoeba.', Parasitology research, vol. 117, no. 5, pp. 1409-1417.View/Download from: UTS OPUS or Publisher's site
This work investigated the anti-amoebic activity of two samarium (Sm) complexes, the acyclic complex [bis(picrato)(pentaethylene glycol)samarium(III)] picrate-referred to as [Sm(Pic)2(EO5)](Pic)-and the cyclic complex [bis(picrato)(18-crown-6)samarium(III)] picrate-referred to as [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morphological transformation of the protozoa Acanthamoeba from its native trophozoite form carrying a spine-like structure called acanthopodia, to round-shaped cells with loss of the acanthopodia structure, a trademark response to environmental stress. Further investigation, however, revealed that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic complex (0.7 μg/mL) was ~ 10-fold lower than IC50 of the cyclic Sm complex (6.5 μg/mL). Secondly, treatment of the Acanthamoeba with the acyclic complex caused apoptosis of the treated cells, while the treatment with the cyclic complex caused necrosis evident by the leakage of the cell membrane. Both treatments induced DNA damage in Acanthamoeba. Finally, a molecular docking simulation revealed the potential capability of the acyclic complex to form hydrogen bonds with profilin-a membrane protein present in eukaryotes, including Acanthamoeba, that plays important roles in the formation and degradation of actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at least in part, for the much higher cytotoxicity of the acyclic complex and also possibly, for the observed differences in the cytotoxicity traits. Nonetheless, with IC50 values of < 10 μg/mL, both the acyclic and cyclic Sm complexes feature a promising potential as cytotoxic agents to fight amoebic infections.
Kusrini, E, Wicaksono, W, Gunawan, C, Daud, NZA & Usman, A 2018, 'Kinetics, mechanism, and thermodynamics of lanthanum adsorption on pectin extracted from durian rind', Journal of Environmental Chemical Engineering, vol. 6, no. 5, pp. 6580-6588.View/Download from: UTS OPUS or Publisher's site
© 2018 Elsevier Ltd. All rights reserved. The rare-earth elements in aqueous waste streams have received great attention due to their potential to pollute the environment. Lanthanum is one of the most used rare-earth elements in industries and disposed as waste. Several efforts have been devoted to remove lanthanum from waste water systems. This study was focused on the adsorption of lanthanum from aqueous solutions by using pectin extracted from durian rind, which is home and industrial waste of durian fruit. Adsorption experiments were carried out in batch method, and the effects of contact time, initial concentration of lanthanum ion, pH of medium, pectin dosage, and temperature on the adsorption efficiency were investigated. The kinetics, mechanism, and thermodynamics of lanthanum adsorption on the pectin were also evaluated. The results demonstrated that the pectin as a cost-effective biosorbent could remove lanthanum with efficiency as high as 41.2 mg/g (at the optimum conditions: pH 4.0, 25 °C, 90 min). The adsorption process of lanthanum on the pectin is well described by either Freundlich or Temkin isotherm model, indicating that adsorption occurs mainly on multilayers and heterogeneous surfaces of pectin. Thermodynamic quantities suggested that the adsorption of lanthanum on the pectin was exothermic and spontaneous, and the reaction was feasible. We also showed that the spent adsorbent can be regenerated up to a limited number of times, upon strong base treatment.
Liana, AE, Marquis, CP, Gunawan, C, Justin Gooding, J & Amal, R 2018, 'Antimicrobial activity of T4 bacteriophage conjugated indium tin oxide surfaces.', Journal of colloid and interface science, vol. 514, pp. 227-233.View/Download from: UTS OPUS or Publisher's site
We report the antimicrobial activity of bare and surface functionalized indium tin oxide (ITO) conjugated with T4 bacteriophage towards E. coli. A ∼ 103-fold reduction (99.9%) in the bacterial concentration was achieved within 2 h exposure of E. coli to the bare as well as the amine, carboxylic and methyl functionalized ITO/T4 surfaces. Despite the known differences in bacteriophage loading of these ITO/T4 systems, the almost identical extent of antimicrobial activity of all of the ITO/T4 systems resulted from the release of a comparable amount of infective T4 from the systems. As anticipated, a single dose of immobilized bacteriophage was sufficient to eliminate further surge of bacterial population. Upon the 2 h eradication of the '1st batch' of E. coli population, all of the ITO/T4 systems, each system with 102-fold more suspended bacteriophage (due to propagation of the phage at the expense of the '1st batch' E. coli death), reduced the '2nd batch' of E. coli concentration by ∼104-fold in just 30 min, suggesting the potential of immobilized bacteriophage systems as solution to the issues of antimicrobial agent depletion. All of the ITO/T4 systems maintained their antimicrobial activity in the presence of model food components. The antimicrobial activity was however, affected by pH; at pH 5 whereby the bacteria's growth was physiologically inhibited, generally no reduction in E. coli concentration was detected. The present work provides an understanding of the mode of antimicrobial activity exhibited by an immobilized bacteriophage based substrate and demonstrates efficacy in the presence of food components.
Wonoputri, V, Gunawan, C, Liu, S, Barraud, N, Yee, LH, Lim, M & Amal, R 2018, 'Ferrous ion as a reducing agent in the generation of antibiofilm nitric oxide from a copper-based catalytic system.', Nitric oxide : biology and chemistry, vol. 75, pp. 8-15.View/Download from: UTS OPUS or Publisher's site
The work found that the electron-donating properties of ferrous ions (Fe2+) can be used for the conversion of nitrite (NO2-) into the biofilm-dispersing signal nitric oxide (NO) by a copper(II) complex (CuDTTCT) catalyst, a potentially applicable biofilm control technology for the water industries. The availability of Fe2+ varied depending on the characteristics of the aqueous systems (phosphate- and carbonate-containing nitrifying bacteria growth medium, NBGM and phosphate buffered saline, PBS at pH 6 to 8, to simulate conditions typically present in the water industries) and was found to affect the production of NO from nitrite by CuDTTCT (casted into PVC). Greater amounts of NO were generated from the CuDTTCT-nitrite-Fe2+ systems in PBS compared to those in NBGM, which was associated with the reduced extent of Fe2+-to-Fe3+ autoxidation by the iron-precipitating moieties phosphates and carbonate in the former system. Further, acidic conditions at pH 6.0 were found to favor NO production from the catalytic system in both PBS and NBGM compared to neutral or basic pH (pH 7.0 or 8.0). Lower pH was shown to stabilize Fe2+ and reduce its autoxidation to Fe3+. These findings will be beneficial for the potential implementation of the NO-generating catalytic technology and indeed, a 'non-killing' biofilm dispersal activity of CuDTTCT-nitrite-Fe2+ was observed on nitrifying bacteria biofilms in PBS at pH 6.
Gunawan, C, Marquis, CP, Amal, R, Sotiriou, GA, Rice, SA & Harry, EJ 2017, 'Widespread and Indiscriminate Nanosilver Use: Genuine Potential for Microbial Resistance.', ACS Nano, vol. 11, no. 4, pp. 3438-3445.View/Download from: UTS OPUS or Publisher's site
In this era of increasing antibiotic resistance, the use of alternative antimicrobials such as silver has become more widespread. Superior antimicrobial activity has been provided through fabrication of silver nanoparticles or nanosilver (NAg), which imparts cytotoxic actions distinct from those of bulk silver. In the wake of the recent discoveries of bacterial resistance to NAg and its rising incorporation in medical and consumer goods such as wound dressings and dietary supplements, we argue that there is an urgent need to monitor the prevalence and spread of NAg microbial resistance. In this Perspective, we describe how the use of NAg in commercially available products facilitates prolonged microorganism exposure to bioavailable silver, which underpins the development of resistance. Furthermore, we advocate for a judicial approach toward NAg use in order to preserve its efficacy and to avoid environmental disruption.
Liana, AE, Marquis, CP, Gunawan, C, Gooding, JJ & Amal, R 2017, 'T4 Bacteriophage Conjugated Magnetic Particles for E. coli Capturing: Influence of Bacteriophage Loading, Temperature and Tryptone', Colloids and Surfaces B: Biointerfaces, vol. 151, pp. 47-57.View/Download from: UTS OPUS or Publisher's site
This work demonstrates the use of bacteriophage conjugated magnetic particles (Fe3O4) for the rapid capturing and isolation of Escherichia coli. The investigation of T4 bacteriophage adsorption to silane functionalised Fe3O4 with amine (single bondNH2), carboxylic (single bondCOOH) and methyl (single bondCH3) surface functional groups reveals the domination of net electrostatic and hydrophobic interactions in governing bacteriophage adsorption. The bare Fe3O4 and Fe3O4-NH2 with high T4 loading captured 3-fold more E. coli (∼70% capturing efficiency) compared to the low loading T4 on Fe3O4-COOH, suggesting the significance of T4 loading in E. coli capturing efficiency. Importantly, it is further revealed that E. coli capture is highly dependent on the incubation temperature and the presence of tryptone in the media. Effective E. coli capturing only occurs at 37 °C in tryptone-containing media with the absence of either conditions resulted in poor bacteria capture. The incubation temperature dictates the capturing ability of Fe3O4/T4, whereby T4 and E. coli need to establish an irreversible binding that occurred at 37 °C. The presence of tryptophan-rich tryptone in the suspending media was also critical, as shown by a 3-fold increase in E. coli capture efficiency of Fe3O4/T4 in tryptone-containing media compared to that in tryptone-free media. This highlights for the first time that successful bacteria capturing requires not only an optimum tailoring of the particle’s surface physicochemical properties for favourable bacteriophage loading, but also an in-depth understanding of how factors, such as temperature and solution chemistry influence the subsequent bacteriophage-bacteria interactions.
Liana, AE, Chia, EW, Marquis, CP, Gunawan, C, Gooding, JJ & Amal, R 2016, 'Adsorption of T4 bacteriophages on planar indium tin oxide surface via controlled surface tailoring', JOURNAL OF COLLOID AND INTERFACE SCIENCE, vol. 468, pp. 192-199.View/Download from: UTS OPUS or Publisher's site
Liu, S, Gunawan, C, Barraud, N, Rice, SA, Harry, EJ & Amal, R 2016, 'Understanding, Monitoring, and Controlling Biofilm Growth inDrinking Water Distribution Systems', Environmental Science and Technology (Washington), vol. 50, pp. 8954-8976.View/Download from: UTS OPUS or Publisher's site
In drinking water distribution systems (DWDS), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (EPS) protecting the biomass from environmental and shear stresses. Biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. This article critically reviews important research findings on biofilm growth in DWDS, examining the factors affecting their formation and characteristics as well as the various technologies to characterize and monitor and, ultimately, to control their growth. Research indicates that temperature fluctuations potentially affect not only the initial bacteria-to-surface attachment but also the growth rates of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria; ammonia-oxidizing bacteria, for example, grow more-developed biofilms at a typical summer temperature of 22 °C compared to 12 °C in fall, and the opposite occurs for the pathogenic Vibrio cholerae. Recent investigations have found the formation of thinner yet denser biofilms under high and turbulent flow regimes of drinking water, in comparison to the more porous and loosely attached biofilms at low flow rates. Furthermore, in addition to the rather well-known tendency of significant biofilm growth on corrosion-prone metal pipes, research efforts also found leaching of growth-promoting organic compounds from the increasingly popular use of polymer-based pipes. Knowledge of the unique microbial members of drinking water biofilms and, importantly, the influence of water characteristics and operational conditions on their growth can be applied to optimize various operational parameters to minimize biofilm accumulation. More-detailed characterizations of the biofilm population size and structure are now...
Wonoputri, V, Gunawan, C, Liu, S, Barraud, N, Yee, LH, Lim, M & Amal, R 2016, 'Iron Complex Facilitated Copper Redox Cycling for Nitric Oxide Generation as Nontoxic Nitrifying Biofilm Inhibitor', ACS APPLIED MATERIALS & INTERFACES, vol. 8, no. 44, pp. 30502-30510.View/Download from: UTS OPUS or Publisher's site
Wonoputri, V, Gunawan, C, Liu, S, Barraud, N, Yee, LH, Lim, M & Amal, R 2015, 'Copper complex in polyvinyl chloride as nitric oxide generating catalyst for the control of nitrifying bacterial biofilms', ACS Applied Materials & Interfaces, vol. 7, pp. 22148-22156.View/Download from: UTS OPUS or Publisher's site
In this study, catalytic generation of nitric oxide by a copper(II) complex embedded within a poly(vinyl chloride) matrix in the presence of nitrite (source of nitric oxide) and ascorbic acid (reducing agent) was shown to effectively control the formation and dispersion of nitrifying bacteria biofilms. Amperometric measurements indicated increased and prolonged generation of nitric oxide with the addition of the copper complex when compared to that with nitrite and ascorbic acid alone. The effectiveness of the copper complex–nitrite–ascorbic acid system for biofilm control was quantified using protein analysis, which showed enhanced biofilm suppression when the copper complex was used in comparison to that with nitrite and ascorbic acid treatment alone. Confocal laser scanning microscopy (CLSM) and LIVE/DEAD staining revealed a reduction in cell surface coverage without a loss of viability with the copper complex and up to 5 mM of nitrite and ascorbic acid, suggesting that the nitric oxide generated from the system inhibits proliferation of the cells on surfaces. Induction of nitric oxide production by the copper complex system also triggered the dispersal of pre-established biofilms. However, the addition of a high concentration of nitrite and ascorbic acid to a pre-established biofilm induced bacterial membrane damage and strongly decreased the metabolic activity of planktonic and biofilm cells, as revealed by CLSM with LIVE/DEAD staining and intracellular adenosine triphosphate measurements, respectively. This study highlights the utility of the catalytic generation of nitric oxide for the long-term suppression and removal of nitrifying bacterial biofilms.
Gunawan, C, Lim, M, Marquis, CP & Amal, R 2014, 'Nanoparticle-protein corona complexes govern the biological fates and functions of nanoparticles', Journal of Materials Chemistry B, vol. 2, no. 15, pp. 2060-2083.View/Download from: UTS OPUS or Publisher's site
Upon contact with plasma or other protein-containing biological fluids, the surface of nanoparticles is immediately decorated with proteins forming a biologically active protein corona. The biological fates and functions of nanoparticles are determined by physiological responses toward these nanoparticle-protein corona complexes as the effective biological unit of nanoparticles. In this article, we review representative studies on the effects of particle physicochemical characteristics along with the protein profiles in the biological medium on the formation of protein corona and importantly, how the dynamic nature and protein fingerprints of the formed corona govern the biological responses toward nanoparticles. The biological effects arising from the presence of protein corona can be both beneficial and unfavourable to the biomedical applications of nanoparticles. The protein corona-cell interactions open up the feasibility of targeted delivery and cell-specific uptake of therapeutic nanoparticles and in other circumstances, engineering of nanoparticles as adjuvants for vaccine development as well as mitigation of the unintentional cytotoxic effects of nanoparticles. On the other hand, the protein corona-cell interactions could induce rapid clearance of nanoparticles from in vivo circulation as well as activating unwanted inflammatory responses. Taken together, the knowledge on the formation and biological effects of protein corona enables tailored tuning of the physicochemical characteristics of nanoparticles, unique to their intended biological activity. © 2014 the Partner Organisations.
Limbri, H, Gunawan, C, Thomas, T, Smith, A, Scott, J & Rosche, B 2014, 'Coal-packed methane biofilter for mitigation of green house gas emissions from coal mine ventilation air.', PLoS ONE, vol. 9, no. 4, pp. 1-9.View/Download from: UTS OPUS or Publisher's site
Methane emitted by coal mine ventilation air (MVA) is a significant greenhouse gas. A mitigation strategy is the oxidation of methane to carbon dioxide, which is approximately twenty-one times less effective at global warming than methane on a mass-basis. The low non-combustible methane concentrations at high MVA flow rates call for a catalytic strategy of oxidation. A laboratory-scale coal-packed biofilter was designed and partially removed methane from humidified air at flow rates between 0.2 and 2.4 L min-1 at 30°C with nutrient solution added every three days. Methane oxidation was catalysed by a complex community of naturally-occurring microorganisms, with the most abundant member being identified by 16S rRNA gene sequence as belonging to the methanotrophic genus Methylocystis. Additional inoculation with a laboratory-grown culture of Methylosinus sporium, as investigated in a parallel run, only enhanced methane consumption during the initial 12 weeks. The greatest level of methane removal of 27.2±0.66 g methane m-3 empty bed h-1 was attained for the non-inoculated system, which was equivalent to removing 19.7±2.9% methane from an inlet concentration of 1% v/v at an inlet gas flow rate of 1.6 L min-1 (2.4 min empty bed residence time). These results show that low-cost coal packing holds promising potential as a suitable growth surface and contains methanotrophic microorganisms for the catalytic oxidative removal of methane.
Liu, S, Killen, E, Lim, M, Gunawan, C & Amal, R 2014, 'The effect of common bacterial growth media on zinc oxide thin films: Identification of reaction products and implications for the toxicology of ZnO', RSC Advances, vol. 4, no. 9, pp. 4363-4370.View/Download from: UTS OPUS or Publisher's site
This study provides a thorough investigation on the effects of the commonly-employed microbial growth medium, namely the peptide-containing luria-bertani broth, tryptic soy broth, the glucose-containing M9 Minimal Salts Media as well as phosphate-buffered saline solution on the dissolution and microstructural transformation of zinc oxide thin film. Morphology and chemical composition of the ZnO film after incubation in the media was thoroughly characterised. In addition, the amount and rate of soluble zinc released by the ZnO thin films was quantified. Exposure of ZnO thin film in the different growth media saw formation of new zinc compounds, resulting from various chemical reactions of zinc with the medium components. Deposition of the new zinc compounds on top of the thin film caused morphological transformation of the film. Zinc leaching was observed in all of the tested media, with significantly higher extent of dissolution observed in peptide-containing organic media, such as luria bertani and tryptic soy broth. Complex organic components, such as amino acids and peptides form complexes with zinc oxide coatings, resulting in complexation-mediated leaching of zinc. Soluble zinc re-precipitates with components in the media, and therefore substantially reduced the amount of dissolved zinc. The results suggest strong influence of solution chemistry on ZnO speciation in a test medium, which have important implications for the mechanistic interpretation of ZnO toxicity. © 2014 The Royal Society of Chemistry.
Gunawan, C, Sirimanoonphan, A, Teoh, WY, Marquis, CP & Amal, R 2013, 'Submicron and nano formulations of titanium dioxide and zinc oxide stimulate unique cellular toxicological responses in the green microalga Chlamydomonas reinhardtii', JOURNAL OF HAZARDOUS MATERIALS, vol. 260, pp. 984-992.View/Download from: UTS OPUS or Publisher's site
Gunawan, C, Teoh, WY, Marquis, CP & Amal, R 2013, 'Induced Adaptation of Bacillus sp. to Antimicrobial Nanosilver', SMALL, vol. 9, no. 21, pp. 3554-3560.View/Download from: UTS OPUS or Publisher's site
Gunawan, C, Teoh, WY, Ricardo, Marquis, CP & Amal, R 2013, 'Zinc Oxide Nanoparticles Induce Cell Filamentation in Escherichia coli', PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, vol. 30, no. 4, pp. 375-380.View/Download from: UTS OPUS or Publisher's site
Limbri, H, Gunawan, C, Rosche, B & Scott, J 2013, 'Challenges to Developing Methane Biofiltration for Coal Mine Ventilation Air: A Review', WATER AIR AND SOIL POLLUTION, vol. 224, no. 6.View/Download from: UTS OPUS or Publisher's site
Lord, MS, Tsoi, B, Gunawan, C, Teoh, WY, Amal, R & Whitelock, JM 2013, 'Anti-angiogenic activity of heparin functionalised cerium oxide nanoparticles', BIOMATERIALS, vol. 34, no. 34, pp. 8808-8818.View/Download from: UTS OPUS or Publisher's site
Ting, S, Whitelock, JM, Tomic, R, Gunawan, C, Teoh, W, Amal, R & Lord, MS 2013, 'Cellular uptake and activity of heparin functionalised cerium oxide nanoparticles', Biomaterials, vol. 34, no. 17, pp. 4377-4386.View/Download from: UTS OPUS or Publisher's site
Cerium oxide nanoparticles (nanoceria) are effective in scavenging intracellular reactive oxygen species (ROS). In this study nanoceria synthesized by flame spray pyrolysis (dXRD Â¼ 12 nm) were functionalised with heparin via an organosilane linker, 3-aminopropyltriethoxysilane. Nanoceria were functionalised with approximately 130 heparin molecules per nanoparticle as determined by thermo gravimetric analysis. Heparin functionalised nanoceria were more effectively internalised by the human monocyte cell line, U937, and U937 cells that had been activated with phorbol 12 myristate 13-acetate (PMA) than bare nanoceria. The heparin functionalised nanoceria were also more effective in scavenging ROS than nanoceria in both activated and unactivated U937 cells. Heparin coupled nanoceria were found to be biologically active due to their ability to bind fibroblast growth factor 2 and signal through FGF receptor 1. Additionally, the heparin-coupled nanoceria, once internalised by the cells, were found to be degraded by 48 h. Together these data demonstrated that heparin enhanced the biological properties of nanoceria in terms of cellular uptake and ROS scavenging, while the nanoceria themselves were more effective at delivering heparin intracellularly than exposing cells to heparin in solution.
Lord, MS, Jung, M, Teoh, WY, Gunawan, C, Vassie, JA, Amal, R & Whitelock, JM 2012, 'Cellular uptake and reactive oxygen species modulation of cerium oxide nanoparticles in human monocyte cell line U937', Biomaterials, vol. 33, no. 31, pp. 7915-7924.View/Download from: UTS OPUS or Publisher's site
Cerium oxide nanoparticles (nanoceria) are promising materials for intracellular oxygen free radical scavenging providing a potential therapy for reactive oxygen species (ROS)-mediated inflammatory processes. In this study rhombohedral-shaped nanoceria were synthesized by flame spray pyrolysis with tuneable particle diameters between 3 and 94 nm by changing the liquid precursor flow rate. Monocytes and macrophages are major players in inflammatory processes as their production of ROS species has important downstream effects on cell signalling. Therefore, this study examined the ability of the nanoceria to be internalised by the human monocytic cell line, U937, and scavenge intracellular ROS. U937 cells activated in the presence of phorbol 12-myristate 13-acetate (PMA) were found to be more responsive to the nanoceria than U937 cells, which may not be surprising given the role of monocyte/macrophages in phagocytosing foreign material. The smaller particles were found to contain more crystal lattice defects with which to scavenge ROS, however a greater proportion of both the U937 and activated U937 cell populations responded to the larger particles. Hence all nanoceria particle sizes examined in this study were equally effective in scavenging intracellular ROS.
Gunawan, C, Teoh, WY, Marquis, CP & Amal, R 2011, 'Cytotoxic Origin of Copper(II) Oxide Nanoparticles: Comparative Studies with Micron-Sized Particles, Leachate, and Metal Salts', ACS NANO, vol. 5, no. 9, pp. 7214-7225.View/Download from: UTS OPUS or Publisher's site
Gunawan, C, Breuer, M, Hauer, B, Rogers, PL & Rosche, B 2008, 'Improved (R)-phenylacetylcarbinol production with Candida utilis pyruvate decarboxylase at decreased organic to aqueous phase volume ratios', BIOTECHNOLOGY LETTERS, vol. 30, no. 2, pp. 281-286.View/Download from: UTS OPUS or Publisher's site
Kusrini, E, Wicaksono, B, Yulizar, Y, Prasetyanto, EA & Gunawan, C 2017, 'Textile Dye Removal from Aqueous Solution using Modified Graphite Waste/Lanthanum/Chitosan Composite', IOP Conference Series: Materials Science and Engineering, Quality in Research: International Symposium on Materials, Metallurgy, and Chemical Engineering, IOP, Bali, Indonesia.View/Download from: UTS OPUS or Publisher's site
© Published under licence by IOP Publishing Ltd. We investigated various pre-treatment processes of graphite waste using thermal, mechanical and chemical methods. The aim of this work is to study the performance of modified graphite waste/lanthanum/chitosan composite (MG) as adsorbent for textile dye removal from aqueous solution. Effect of graphite waste resources, adsorbent size and lanthanum concentration on the dye removal were studied in batch experiments. Selectivity of MG was also investigated. Pre-heated graphite waste (NMG) was conducted at 80°C for 1 h, followed by mechanical crushing of the resultant graphite to 75 μm particle size, giving adsorption performance of ∼58%, ∼67%, ∼93% and ∼98% of the model dye rhodamine B (concentration determined by UV-vis spectroscopy at 554 nm), methyl orange (464 nm), methylene blue (664 nm) and methyl violet (580 nm), respectively from aqueous solution. For this process, the system required less than ∼5 min for adsorbent material to be completely saturated with the adsorbate. Further chemical modification of the pre-treated graphite waste (MG) with lanthanum (0.01 - V 0.03 M) and chitosan (0.5% w/w) did not improve the performance of dye adsorption. Under comparable experimental conditions, as those of the 'thermal-mechanical-pre-treated-only' (NMG), modification of graphite waste (MG) with 0.03 M lanthanum and 0.5% w/w chitosan resulted in ∼14%, ∼47%, ∼72% and ∼85% adsorption of rhodamine B, methyl orange, methylene blue and methyl violet, respectively. Selective adsorption of methylene blue at most to ∼79%, followed by methyl orange, methyl violet and rhodamine B with adsorption efficiency ∼67, ∼38, and ∼9% sequentially using MG with 0.03 M lanthanum and 0.5% w/w chitosan.
Kusrini, E, Lukita, M, Gozan, M, Susanto, BH, Nasution, DA, Rahman, A & Gunawan, C 2016, 'Enrichment process of biogas using simultaneous Absorption - Adsorption methods', AIP Conference Proceedings, Renewable Energy Technology and Innovation for Sustainable Development, i-TREC.View/Download from: UTS OPUS or Publisher's site
© 2017 Author(s). Removal of CO2in biogas is an essential methods to the purification and upgrading of biogas. Natural Clinoptilolite zeolites were evaluated as sorbents for purification of biogas that produced from palm oil mill effluent (POME) by anerobic-digestion method. The absorption and adsorption experiments were conducted in a fixed-bed two column adsorption unit by simultaneous absorption-adsorption method. The Ca(OH)2solution with concentration of 0.062 M was used as absorption method. Sorbent for removal of CO2in biogas have been prepared by modifying of Clinoptilolite zeolites with an acid (HCl, 2M) and alkaline (NaOH, 2M), calcined at 450°C and then coated using chitosan (0.5 w/v%) in order to increase their adsorption capacity. The removal of CO2in biogas was achieved about ∼83% using 2.5?g of sorbent zeolite (2M)/chitosan dosage for each column, breakthrough time of 30?min, and flow rate of 100?mL/min. Clinoptilolite zeolites with modifications of an acid-alkaline and chitosan (zeolite (2M)/chitosan) are promising sorbents due to the amine groups from chitosan and high surface-volume ratio are one of important factors in a simultaneous absorption-adsorption method.
Kusrini, E, Prassanti, R, Nurjaya, DM & Gunawan, C 2017, 'Multifunctional microsphere formulation of fluorescent magnetic properties for drug delivery system', AIP Conference Proceedings.View/Download from: UTS OPUS or Publisher's site
© 2017 Author(s). The microsphere formulations of Chit/TPP/Sm/Fe3O4/Rn were prepared by an ionic gelation technique, where Chit=chitosan, TPP=tripolyphosphate, Sm=samarium and Rn=ranitidine. Optimum of microsphere formulation exhibit magnetic and fluorescent properties with adsorption efficiency of ∼92% was obtained for Chit/TPP/Sm/Fe3O4/Rn with ratio 400:500:50:1:20. Fluorescence intensity of microsphere formulations increased with the cumulative amount release of ranitidine, so that the changing of fluorescence intensity at wavelength of 590 nm referring to the Sm3+ ion could be used as indicator in DDS. With the demonstration of sustained release from microsphere formulation, it allows to investigate the applications to other drugs.
Gunawan, C, Liu, S, Barraud, N, Lim, M, Rice, S & Amal, R 2012, 'Zinc Oxide-Silica Coatings for the Reduction of Pseudomonas aeruginosa Proliferation and Biofilm Formation', International Conference on Nanoscience and Nanotechnology, Perth.