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Dr. Anthony Slate
University of Bath

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0 Electrochemistry
0 Medical Microbiology
0 Surface Analysis
0 Catheter associated urinary tract infection
0 Microbial Fuel Cells

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Antimicrobial agents
Microbial Fuel Cells
Electrochemistry

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Article
Published: 01 July 2021 in Pure and Applied Chemistry
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The development of self-cleaning biomimetic surfaces has the potential to be of great benefit to human health, in addition to reducing the economic burden on industries worldwide. Consequently, this study developed a biomimetic wax surface using a moulding technique which emulated the topography of the self-cleaning Gladiolus hybridus (Gladioli) leaf. A comparison of topographies was performed for unmodified wax surfaces (control), biomimetic wax surfaces, and Gladioli leaves using optical profilometry and scanning electron microscopy. The results demonstrated that the biomimetic wax surface and Gladioli leaf had extremely similar surface roughness parameters, but the water contact angle of the Gladioli leaf was significantly higher than the replicated biomimetic surface. The self-cleaning properties of the biomimetic and control surfaces were compared by measuring their propensity to repel Escherichia coli and Listeria monocytogenes attachment, adhesion, and retention in mono- and co-culture conditions. When the bacterial assays were carried out in monoculture, the biomimetic surfaces retained fewer bacteria than the control surfaces. However, when using co-cultures of the bacterial species, only following the retention assays were the bacterial numbers reduced on the biomimetic surfaces. The results demonstrate that such surfaces may be effective in reducing biofouling if used in the appropriate medical, marine, and industrial scenarios. This study provides valuable insight into the anti-fouling physical and chemical control mechanisms found in plants, which are particularly appealing for engineering purposes.

ACS Style

Jake McClements; Luciana C. Gomes; Joshua Spall; Fabien Saubade; Devine Akhidime; Marloes Peeters; Filipe J. Mergulhão; Kathryn A. Whitehead. Celebrating the centenary in polymer science: Drawing inspiration from nature to develop anti-fouling coatings. The development of biomimetic polymer surfaces and their effect on bacterial fouling. Pure and Applied Chemistry 2021, 1 .

AMA Style

Jake McClements, Luciana C. Gomes, Joshua Spall, Fabien Saubade, Devine Akhidime, Marloes Peeters, Filipe J. Mergulhão, Kathryn A. Whitehead. Celebrating the centenary in polymer science: Drawing inspiration from nature to develop anti-fouling coatings. The development of biomimetic polymer surfaces and their effect on bacterial fouling. Pure and Applied Chemistry. 2021; ():1.

Chicago/Turabian Style

Jake McClements; Luciana C. Gomes; Joshua Spall; Fabien Saubade; Devine Akhidime; Marloes Peeters; Filipe J. Mergulhão; Kathryn A. Whitehead. 2021. "Celebrating the centenary in polymer science: Drawing inspiration from nature to develop anti-fouling coatings. The development of biomimetic polymer surfaces and their effect on bacterial fouling." Pure and Applied Chemistry , no. : 1.

Journal article
Published: 29 June 2021 in Langmuir
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It is well established that many leaf surfaces display self-cleaning properties. However, an understanding of how the surface properties interact is still not achieved. Consequently, 12 different leaf types were selected for analysis due to their water repellency and self-cleaning properties. The most hydrophobic surfaces demonstrated splitting of the νs CH2 and ν CH2 bands, ordered platelet-like structures, crystalline waxes, high-surface-roughness values, high-total-surface-free energy and apolar components of surface energy, and low polar and Lewis base components of surface energy. The surfaces that exhibited the least roughness and high polar and Lewis base components of surface energy had intracuticular waxes, yet they still demonstrated the self-cleaning action. Principal component analysis demonstrated that the most hydrophobic species shared common surface chemistry traits with low intra-class variability, while the less hydrophobic leaves had highly variable surface-chemistry characteristics. Despite this, we have shown through partial least squares regression that the leaf water contact angle (i.e., hydrophobicity) can be predicted using attenuated total reflectance Fourier transform infrared spectroscopy surface chemistry data with excellent ability. This is the first time that such a statistical analysis has been performed on a complex biological system. This model could be utilized to investigate and predict the water contact angles of a range of biological surfaces. An understanding of the interplay of properties is extremely important to produce optimized biomimetic surfaces.

ACS Style

Fabien Saubade; Lisa I. Pilkington; Christopher M. Liauw; Luciana C. Gomes; Jake McClements; Marloes Peeters; Mohamed El Mohtadi; Filipe J. Mergulhão; Kathryn A. Whitehead. Principal Component Analysis to Determine the Surface Properties That Influence the Self-Cleaning Action of Hydrophobic Plant Leaves. Langmuir 2021, 1 .

AMA Style

Fabien Saubade, Lisa I. Pilkington, Christopher M. Liauw, Luciana C. Gomes, Jake McClements, Marloes Peeters, Mohamed El Mohtadi, Filipe J. Mergulhão, Kathryn A. Whitehead. Principal Component Analysis to Determine the Surface Properties That Influence the Self-Cleaning Action of Hydrophobic Plant Leaves. Langmuir. 2021; ():1.

Chicago/Turabian Style

Fabien Saubade; Lisa I. Pilkington; Christopher M. Liauw; Luciana C. Gomes; Jake McClements; Marloes Peeters; Mohamed El Mohtadi; Filipe J. Mergulhão; Kathryn A. Whitehead. 2021. "Principal Component Analysis to Determine the Surface Properties That Influence the Self-Cleaning Action of Hydrophobic Plant Leaves." Langmuir , no. : 1.

Journal article
Published: 31 May 2021 in Food Research International
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A novel concept of stabilizing multiple-phase food structure such as emulsion using solely the constitutional bacteria enables an all-natural food grade formulation and thus a clean label declaration. In this paper, we propose an efficient approach to hydrophobically modifying the surface of lactic acid bacteria Lactobacillus rhamnosus (LGG) using lauroyl ahloride (LC) in non-aqueous media. Compared to the unmodified bacteria, cell hydrophobicity was dramatically altered upon modification, according to the higher percentages of microbial adhesion to hexadecane (MATH) and water contact angles (WCA) of LC-modified bacteria. No evident changes were found in bacterial surface charge before and after LC modification. By using one-step homogenization, all the modified bacteria were able to generate stabile water-in-oil-in-water (W/O/W) double emulsions where bacteria were observed on oil–water interfaces of the primary and secondary droplets. Modification using high LC concentrations (10 and 20 w/w%) led to rapid autoaggregation of bacteria in aqueous solution. A long-term lethal effect of modification primarily came from lyophilization and no apparent impact was detected on the instantaneous culturability of modified bacteria.

ACS Style

Xiaoyi Jiang; Elhamalsadat Shekarforoush; Musemma Kedir Muhammed; Kathryn Whitehead; Adam Cohen Simonsen; Nils Arneborg; Jens Risbo. Efficient chemical hydrophobization of lactic acid bacteria – One-step formation of double emulsion. Food Research International 2021, 147, 110460 .

AMA Style

Xiaoyi Jiang, Elhamalsadat Shekarforoush, Musemma Kedir Muhammed, Kathryn Whitehead, Adam Cohen Simonsen, Nils Arneborg, Jens Risbo. Efficient chemical hydrophobization of lactic acid bacteria – One-step formation of double emulsion. Food Research International. 2021; 147 ():110460.

Chicago/Turabian Style

Xiaoyi Jiang; Elhamalsadat Shekarforoush; Musemma Kedir Muhammed; Kathryn Whitehead; Adam Cohen Simonsen; Nils Arneborg; Jens Risbo. 2021. "Efficient chemical hydrophobization of lactic acid bacteria – One-step formation of double emulsion." Food Research International 147, no. : 110460.

Journal article
Published: 05 May 2021 in Journal of Power Sources
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A commercial polylactic acid/graphene (8 wt%) composite filament was used to additive manufacture (AM) graphene macroelectrodes (AM-GMs). The electrode surfaces were characterised and Pseudomonas aeruginosa was utilised as the exoelectrogen. The MFC was optimised using growth kinetic assays, biofilm formation, and quantification of pyocyanin production (via liquid chromatography-mass spectrometry) in conditions that were representative of the batch-fed MFC configuration utilised. Cell potential and bacterial viability was recorded at 0 h, 24 h, 48 h, 72 h, 96 h and 120 h, power density and current density were calculated. There was no significant difference between P. aeruginosa cell proliferation in either media tested. Interestingly, no accumulation of pyocyanin was evident. Additively manufactured electrodes comprised of graphene (AM-GMs) were successfully applied in a P. aeruginosa MFC configuration and power outputs (110.74 ± 14.63 μW m-2) produced were comparable to that of the ‘benchmark’ electrode, carbon cloth (93.49 ± 5.17 μW m-2). The AM-GMs demonstrated power/current outputs similar to that of the carbon cloth electrodes in both anaerobic LB and glucose-based media over 120 h; the AM-GMs had no significant detrimental effect on P. aeruginosa viability. This study highlights the potential application of additive manufactured electrodes with the incorporation of nanomaterials (e.g., graphene) as one approach to enhance power outputs.

ACS Style

Anthony J. Slate; Niall A. Hickey; Jonathan A. Butler; Daniel Wilson; Christopher M. Liauw; Craig E. Banks; Kathryn A. Whitehead. Additive manufactured graphene-based electrodes exhibit beneficial performances in Pseudomonas aeruginosa microbial fuel cells. Journal of Power Sources 2021, 499, 229938 .

AMA Style

Anthony J. Slate, Niall A. Hickey, Jonathan A. Butler, Daniel Wilson, Christopher M. Liauw, Craig E. Banks, Kathryn A. Whitehead. Additive manufactured graphene-based electrodes exhibit beneficial performances in Pseudomonas aeruginosa microbial fuel cells. Journal of Power Sources. 2021; 499 ():229938.

Chicago/Turabian Style

Anthony J. Slate; Niall A. Hickey; Jonathan A. Butler; Daniel Wilson; Christopher M. Liauw; Craig E. Banks; Kathryn A. Whitehead. 2021. "Additive manufactured graphene-based electrodes exhibit beneficial performances in Pseudomonas aeruginosa microbial fuel cells." Journal of Power Sources 499, no. : 229938.

Journal article
Published: 01 April 2021 in iScience
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Summary Binding to surfaces by fungal spores is a prerequisite to biofilm formation. The interactions of polytetrafluoroethylene (PTFE), glass, and silicon with three fungal spores, of differing shapes and sizes (Aspergillus niger 1957, Aspergillus niger 1988, and Aureobasidium pullulans), were investigated. A multifractal analysis was conducted to provide quantitative measures of density, dispersion, and clustering of spores on the surfaces. The PTFE, glass, and silicon surfaces presented a range of surface topographies and wettabilities. PTFE was the roughest and most non-wettable surface, whereas silicon was the opposite in terms of both these aspects. The A. niger species were more non-wettable than A. pullulans. Overall, A. niger 1957 attached in higher numbers to PTFE, whereas A. niger 1988 and A. pullulans bound in highest numbers to glass. The results of this work demonstrated that the overall substratum surface roughness influenced spore binding rather than the physicochemical or chemical properties of surfaces or spores.

ACS Style

Kathryn A. Whitehead; Christopher M. Liauw; Stephen Lynch; Mohamed El Mohtadi; Mohsin Amin; Andrea Preuss; Ted Deisenroth; Joanna Verran. Diverse surface properties reveal that substratum roughness affects fungal spore binding. iScience 2021, 24, 102333 .

AMA Style

Kathryn A. Whitehead, Christopher M. Liauw, Stephen Lynch, Mohamed El Mohtadi, Mohsin Amin, Andrea Preuss, Ted Deisenroth, Joanna Verran. Diverse surface properties reveal that substratum roughness affects fungal spore binding. iScience. 2021; 24 (4):102333.

Chicago/Turabian Style

Kathryn A. Whitehead; Christopher M. Liauw; Stephen Lynch; Mohamed El Mohtadi; Mohsin Amin; Andrea Preuss; Ted Deisenroth; Joanna Verran. 2021. "Diverse surface properties reveal that substratum roughness affects fungal spore binding." iScience 24, no. 4: 102333.

Journal article
Published: 29 March 2021 in Archives of Microbiology
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Due to the ever-increasing rise of antimicrobial resistant (AMR) bacteria, the development of alternative antimicrobial agents is a global priority. The antimicrobial activity of ionic gold was explored against four Pseudomonas aeruginosa strains with different AMR profiles in order to determine the antimicrobial activity of ionic gold and elucidate the mechanisms of action. Disc diffusion assays (zone of inhibition: ZoI) coupled with minimum inhibitory/bactericidal concentrations (MIC/MBC) were conducted to determine the antimicrobial efficacy of ionic gold. Scanning electron microscopy (SEM) was used to visualise morphological changes to the bacterial cell ultrastructure. Strains with increased AMR were slower to grow which is likely a fitness cost due to the enhanced AMR activity. Although greater concentrations of ionic gold were required to promote antimicrobial activity, ionic gold demonstrated similar antimicrobial values against all strains tested. Lowry assay results indicated that protein leakage was apparent following incubation with ionic gold, whilst SEM revealed cellular ultrastructure damage. This study suggests that the application of ionic gold as an alternative antimicrobial is promising, particularly against AMR P. aeruginosa. The antimicrobial activity of ionic gold against P. aeruginosa could potentially be utilised as an alternative therapeutic option in wound management, an approach that could benefit healthcare systems worldwide.

ACS Style

Miguel Reyes Torres; Anthony J. Slate; Steven F. Ryder; Maliha Akram; Conrado Javier Carrascosa Iruzubieta; Kathryn A. Whitehead. Ionic gold demonstrates antimicrobial activity against Pseudomonas aeruginosa strains due to cellular ultrastructure damage. Archives of Microbiology 2021, 203, 1 -10.

AMA Style

Miguel Reyes Torres, Anthony J. Slate, Steven F. Ryder, Maliha Akram, Conrado Javier Carrascosa Iruzubieta, Kathryn A. Whitehead. Ionic gold demonstrates antimicrobial activity against Pseudomonas aeruginosa strains due to cellular ultrastructure damage. Archives of Microbiology. 2021; 203 (6):1-10.

Chicago/Turabian Style

Miguel Reyes Torres; Anthony J. Slate; Steven F. Ryder; Maliha Akram; Conrado Javier Carrascosa Iruzubieta; Kathryn A. Whitehead. 2021. "Ionic gold demonstrates antimicrobial activity against Pseudomonas aeruginosa strains due to cellular ultrastructure damage." Archives of Microbiology 203, no. 6: 1-10.

Journal article
Published: 19 March 2021 in Coatings
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Due to the ever-increasing burden of antimicrobial-resistant (AMR) bacteria, the development of novel antimicrobial agents and biomaterials to act as carriers and/or potentiate antimicrobial activity is essential. This study assessed the antimicrobial efficacy of the following ionic metals, silver, gold, palladium, platinum, zinc, and gallium alone and in combination with graphene matrices (which were coated via a drop casting coating method). The graphene foam was utilized as a carrier for the ionic metals against both, antibiotic susceptible and resistant bacterial strains of Acinetobacter baumannii, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Ionic gold, palladium and platinum demonstrated the greatest antimicrobial activity against the susceptible and resistant strains. Scanning electron microscopy (SEM) visualized cellular ultrastructure damage, when the bacteria were incubated upon the graphene foam alone. This study suggests that specific metal ions applied in combination with graphene foam could present a potential therapeutic option to treat AMR bacterial infections. The application of the graphene foam as a potential carrier could promote antimicrobial activity, provide a sustained release approach and reduce possible resistance acquisition. In light of this study, the graphene foam and ionic metal combinations could potentially be further developed as part of a wound dressing.

ACS Style

Anthony Slate; Nathalie Karaky; Grace Crowther; Jonathan Butler; Craig Banks; Andrew McBain; Kathryn Whitehead. Graphene Matrices as Carriers for Metal Ions against Antibiotic Susceptible and Resistant Bacterial Pathogens. Coatings 2021, 11, 352 .

AMA Style

Anthony Slate, Nathalie Karaky, Grace Crowther, Jonathan Butler, Craig Banks, Andrew McBain, Kathryn Whitehead. Graphene Matrices as Carriers for Metal Ions against Antibiotic Susceptible and Resistant Bacterial Pathogens. Coatings. 2021; 11 (3):352.

Chicago/Turabian Style

Anthony Slate; Nathalie Karaky; Grace Crowther; Jonathan Butler; Craig Banks; Andrew McBain; Kathryn Whitehead. 2021. "Graphene Matrices as Carriers for Metal Ions against Antibiotic Susceptible and Resistant Bacterial Pathogens." Coatings 11, no. 3: 352.

Journal article
Published: 19 March 2021 in International Journal of Environmental Research and Public Health
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Bacterial retention and organic fouling on meat preparation surfaces can be influenced by several factors. Surfaces with linear topographies and defined chemistries were used to determine how the orientation of the surface features affected cleaning efficacy. Fine polished (irregular linear) stainless steel (FPSS), titanium coated fine polished (irregular linear) stainless steel (TiFP), and topographically regular, linear titanium coated surfaces (RG) were fouled with Escherichia coli mixed with a meat exudate (which was utilised as a conditioning film). Surfaces were cleaned along or perpendicular to the linear features for one, five, or ten wipes. The bacteria were most easily removed from the titanium coated and regular featured surfaces. The direction of cleaning (along or perpendicular to the surface features) did not influence the amount of bacteria retained, but meat extract was more easily removed from the surfaces when cleaned in the direction along the linear surface features. Following ten cleans, there was no significant difference in the amount of cells or meat exudate retained on the surfaces cleaned in either direction. This study demonstrated that for the E. coli cells, the TiFP and RG surfaces were easiest to clean. However, the direction of the clean was important for the removal of the meat exudate from the surfaces.

ACS Style

Adele Evans; Anthony Slate; I. Akhidime; Joanna Verran; Peter Kelly; Kathryn Whitehead. The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies. International Journal of Environmental Research and Public Health 2021, 18, 3198 .

AMA Style

Adele Evans, Anthony Slate, I. Akhidime, Joanna Verran, Peter Kelly, Kathryn Whitehead. The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies. International Journal of Environmental Research and Public Health. 2021; 18 (6):3198.

Chicago/Turabian Style

Adele Evans; Anthony Slate; I. Akhidime; Joanna Verran; Peter Kelly; Kathryn Whitehead. 2021. "The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies." International Journal of Environmental Research and Public Health 18, no. 6: 3198.

Review
Published: 25 January 2021 in Biomarkers
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The significant increase of periodontitis, chronic kidney disease (CKD), Alzheimer’s disease and cancer can be attributed to an ageing population. Each disease produces a range of biomarkers that can be indicative of disease onset and progression. Biomarkers are defined as cellular (intra/extracellular components and whole cells), biochemical (metabolites, ions and toxins) or molecular (nucleic acids, proteins and lipids) alterations which are measurable in biological media such as human tissues, cells or fluids. An interesting group of biomarkers that merit further investigation are the polyamines. The polyamines are a group of molecules consisting of cadaverine, putrescine, spermine and spermidine and these have been implicated in the development of a range of systemic disease, in part due to their production in periodontitis. Cadaverine and putrescine within the periodontal environment have demonstrated cell signalling interfering abilities, by way of leukocyte migration disruption. The polyamines spermine and spermidine in tumour cells have been shown to inhibit cellular apoptosis, effectively prolonging tumorigenesis and continuation of cancer within the host. Polyamine degradation products such as acrolein have been shown to exacerbate renal damage in CKD patients. Thus, the use of such molecules has merit to be utilised in the early indication of such diseases in patients. Graphical Abstract

ACS Style

Mohsin Amin; Shiying Tang; Liliana Shalamanova; Rebecca L. Taylor; Stephen Wylie; Badr M. Abdullah; Kathryn A. Whitehead. Polyamine biomarkers as indicators of human disease. Biomarkers 2021, 26, 77 -94.

AMA Style

Mohsin Amin, Shiying Tang, Liliana Shalamanova, Rebecca L. Taylor, Stephen Wylie, Badr M. Abdullah, Kathryn A. Whitehead. Polyamine biomarkers as indicators of human disease. Biomarkers. 2021; 26 (2):77-94.

Chicago/Turabian Style

Mohsin Amin; Shiying Tang; Liliana Shalamanova; Rebecca L. Taylor; Stephen Wylie; Badr M. Abdullah; Kathryn A. Whitehead. 2021. "Polyamine biomarkers as indicators of human disease." Biomarkers 26, no. 2: 77-94.

Review article
Published: 16 January 2021 in Colloids and Surfaces B: Biointerfaces
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Quantum dots (QDs) are promising nanoscale materials with sizes ranging from 1 to 10 nm, and have exponentially triggered scientific interest worldwide during the past decade. They exhibit size-tunable optical features, zero-dimensional structures, and quantum confinement effects. Moreover, they can be tailored to suit various applications. Phyto-synthesis of fluorescent metal chalcogenide QDs and carbon dots (CDs) is a green, feasible, low-cost, and environmentally safe approach to overcome the limitations of chemical and physical synthesis techniques. Different plant extracts provide several phytochemical constituents with numerous functional moieties for natural capping and stabilization of the synthesized metal chalcogenide QDs and CDs. Therefore, the green synthesis of metal chalcogenide QDs and CDs, their optical and structural properties, and applications such as diagnostics, biosensing, heavy metal detection, and photocatalytic degradation are comprehensively summarized in this review. Furthermore, the biovalorization of agricultural wastes, such as fruit and vegetable peels, is addressed to produce high-value metal chalcogenide QDs and CDs. In addition, the toxicity issues associated with these particles are described for the safe usage of QDs. Challenges that restrict the widespread application of QD particles are discussed along with future perspectives for their commercial, safe, and upscale production.

ACS Style

Basma A. Omran; Kathryn A. Whitehead; Kwang-Hyun Baek. One-pot bioinspired synthesis of fluorescent metal chalcogenide and carbon quantum dots: Applications and potential biotoxicity. Colloids and Surfaces B: Biointerfaces 2021, 200, 111578 .

AMA Style

Basma A. Omran, Kathryn A. Whitehead, Kwang-Hyun Baek. One-pot bioinspired synthesis of fluorescent metal chalcogenide and carbon quantum dots: Applications and potential biotoxicity. Colloids and Surfaces B: Biointerfaces. 2021; 200 ():111578.

Chicago/Turabian Style

Basma A. Omran; Kathryn A. Whitehead; Kwang-Hyun Baek. 2021. "One-pot bioinspired synthesis of fluorescent metal chalcogenide and carbon quantum dots: Applications and potential biotoxicity." Colloids and Surfaces B: Biointerfaces 200, no. : 111578.

Journal article
Published: 17 December 2020 in iScience
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Summary Binding of particles and spores to surfaces is a natural phenomenon which is a prerequisite for biofilm formation. Perpendicular force measurements were carried out using atomic force microscopy cantilevers modified with a polystyrene or glass sphere. The attachment of the spheres was tested against glass, PVAc, p(γ-MPSco-MMA), p(γ-MPS-co-LMA), PMMAsc, and silicon surfaces. The polystyrene spheres demonstrated less varied force and strength of attachment measurement to the surfaces than the glass spheres. The force of attachment of the polystyrene spheres was also influenced by mobility of the co-polymer surfaces. Surface wettability did not affect the force of polystyrene or glass sphere attachment. The force measurements of the non-biological spheres were similar to those seen in biological systems with fungal conidia, and this was due to their size, shape, and binding energies. The use of non-biological systems may present an insight into understanding the fundamentals of more complex biological processes.

ACS Style

Mohsin Amin; Andrea Preuss; Ted Deisenroth; Christopher M. Liauw; Joanna Verran; Kathryn A. Whitehead. Use of spherical particles to understand conidial attachment to surfaces using atomic force microscopy. iScience 2020, 24, 101962 .

AMA Style

Mohsin Amin, Andrea Preuss, Ted Deisenroth, Christopher M. Liauw, Joanna Verran, Kathryn A. Whitehead. Use of spherical particles to understand conidial attachment to surfaces using atomic force microscopy. iScience. 2020; 24 (1):101962.

Chicago/Turabian Style

Mohsin Amin; Andrea Preuss; Ted Deisenroth; Christopher M. Liauw; Joanna Verran; Kathryn A. Whitehead. 2020. "Use of spherical particles to understand conidial attachment to surfaces using atomic force microscopy." iScience 24, no. 1: 101962.

Original article
Published: 28 November 2020 in Journal of Applied Microbiology
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Aims Surgical site, soft tissue and wound infections are some of the most prominent causes of Healthcare associated infections (HCAIs). Developing novel antimicrobial textiles and wound dressings may help alleviate the risk of developing HCAIs. We aimed to determine the antimicrobial efficacy of natural Ugandan bark cloth derived exclusively from the Ficus natalensis tree. Methods and Results Antimicrobial contact and disc diffusion assays, coupled with time‐kill kinetic assays demonstrated that bark cloth inhibited the growth of a clinically relevant Methicillin‐resistant Staphylococcus aureus (MRSA) strain and acted as a bactericidal agent causing a seven‐log reduction in bacterial viability. Scanning electron microscopy was used to reveal morphological changes in the bacterial cell ultrastructure when exposed to bark cloth, which supported a proposed mechanism of antimicrobial activity. Conclusions The observed antimicrobial properties, combined with the physical characteristics elicited by bark cloth, suggest this product is ideally suited for wound and other skin care applications. Significance and Impact of the study This is the first report where a whole bark cloth product made by traditional methods has been employed as an antimicrobial fabric against MRSA. Bark cloth is a highly sustainable and renewable product and this study presents a major advance in the search for natural fabrics which could be deployed for healthcare applications.

ACS Style

Jonathan A. Butler; Anthony J. Slate; David B. Todd; Douglas Airton; Michelle Hardman; Niall A. Hickey; Kirsten Scott; Prabhuraj D. Venkatraman. A traditional Ugandan Ficus natalensis bark cloth exhibits antimicrobial activity against methicillin‐resistant Staphylococcus aureus. Journal of Applied Microbiology 2020, 131, 2 -10.

AMA Style

Jonathan A. Butler, Anthony J. Slate, David B. Todd, Douglas Airton, Michelle Hardman, Niall A. Hickey, Kirsten Scott, Prabhuraj D. Venkatraman. A traditional Ugandan Ficus natalensis bark cloth exhibits antimicrobial activity against methicillin‐resistant Staphylococcus aureus. Journal of Applied Microbiology. 2020; 131 (1):2-10.

Chicago/Turabian Style

Jonathan A. Butler; Anthony J. Slate; David B. Todd; Douglas Airton; Michelle Hardman; Niall A. Hickey; Kirsten Scott; Prabhuraj D. Venkatraman. 2020. "A traditional Ugandan Ficus natalensis bark cloth exhibits antimicrobial activity against methicillin‐resistant Staphylococcus aureus." Journal of Applied Microbiology 131, no. 1: 2-10.

Journal article
Published: 09 October 2020 in International Journal of Environmental Research and Public Health
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The reduction of biofouling and the reduction of cross-contamination in the food industry are important aspects of safety management systems. Polymeric surfaces are used extensively throughout the food production industry and therefore ensuring that effective cleaning regimes are conducted is vital. Throughout this study, the influence of the surface characteristics of three different polymeric surfaces, polytetrafluoroethylene (PTFE), poly(methyl methacrylate) (PMMA) and polyethylene terephthalate (PET), on the removal of Escherichia coli using a wipe clean method utilising 3% sodium hypochlorite was determined. The PTFE surfaces were the roughest and demonstrated the least wettable surface (118.8°), followed by the PMMA (75.2°) and PET surfaces (53.9°). Following cleaning with a 3% sodium hypochlorite solution, bacteria were completely removed from the PTFE surfaces, whilst the PMMA and PET surfaces still had high numbers of bacteria recovered (1.2 × 107 CFU/mL and 6.3 × 107 CFU/mL, respectively). When bacterial suspensions were applied to the surfaces in the presence of a blood conditioning film, cleaning with sodium hypochlorite demonstrated that no bacteria were recovered from the PMMA surface. However, on both the PTFE and PET surfaces, bacteria were recovered at lower concentrations (2.0 × 102 CFU/mL and 1.3 × 103 CFU/mL, respectively). ATP bioluminescence results demonstrated significantly different ATP concentrations on the surfaces when soiled (PTFE: 132 relative light units (RLU), PMMA: 80 RLU and PET: 99 RLU). Following cleaning, both in the presence and absence of a blood conditioning film, all the surfaces were considered clean, producing ATP concentrations in the range of 0–2 RLU. The results generated in this study demonstrated that the presence of a blood conditioning film significantly altered the removal of bacteria from the polymeric surfaces following a standard cleaning regime. Conditioning films which represent the environment where the surface is intended to be used should be a vital part of the test regime to ensure an effective disinfection process.

ACS Style

I. Devine Akhidime; Anthony J. Slate; Anca Hulme; Kathryn A. Whitehead. The Influence of Surface Topography and Wettability on Escherichia coli Removal from Polymeric Materials in the Presence of a Blood Conditioning Film. International Journal of Environmental Research and Public Health 2020, 17, 7368 .

AMA Style

I. Devine Akhidime, Anthony J. Slate, Anca Hulme, Kathryn A. Whitehead. The Influence of Surface Topography and Wettability on Escherichia coli Removal from Polymeric Materials in the Presence of a Blood Conditioning Film. International Journal of Environmental Research and Public Health. 2020; 17 (20):7368.

Chicago/Turabian Style

I. Devine Akhidime; Anthony J. Slate; Anca Hulme; Kathryn A. Whitehead. 2020. "The Influence of Surface Topography and Wettability on Escherichia coli Removal from Polymeric Materials in the Presence of a Blood Conditioning Film." International Journal of Environmental Research and Public Health 17, no. 20: 7368.

Review
Published: 30 September 2020 in Molecules
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Quantum dots (QDs) are fluorescent nanocrystals with superb photo-physical properties. Applications of QDs have been exponentially increased during the past decade. They can be employed in several disciplines, including biological, optical, biomedical, engineering, and energy applications. This review highlights the structural composition and distinctive features of QDs, such as resistance to photo-bleaching, wide range of excitations, and size-dependent light emission features. Physical and chemical preparation of QDs have prominent downsides, including high costs, regeneration of hazardous byproducts, and use of external noxious chemicals for capping and stabilization purposes. To eliminate the demerits of these methods, an emphasis on the latest progress of microbial synthesis of QDs by bacteria, yeast, and fungi is introduced. Some of the biomedical applications of QDs are overviewed as well, such as tumor and microRNA detection, drug delivery, photodynamic therapy, and microbial labeling. Challenges facing the microbial fabrication of QDs are discussed with the future prospects to fully maximize the yield of QDs by elucidating the key enzymes intermediating the nucleation and growth of QDs. Exploration of the distribution and mode of action of QDs is required to promote their biomedical applications.

ACS Style

Mohamed Abdel-Salam; Basma Omran; Kathryn Whitehead; Kwang-Hyun Baek. Superior Properties and Biomedical Applications of Microorganism-Derived Fluorescent Quantum Dots. Molecules 2020, 25, 4486 .

AMA Style

Mohamed Abdel-Salam, Basma Omran, Kathryn Whitehead, Kwang-Hyun Baek. Superior Properties and Biomedical Applications of Microorganism-Derived Fluorescent Quantum Dots. Molecules. 2020; 25 (19):4486.

Chicago/Turabian Style

Mohamed Abdel-Salam; Basma Omran; Kathryn Whitehead; Kwang-Hyun Baek. 2020. "Superior Properties and Biomedical Applications of Microorganism-Derived Fluorescent Quantum Dots." Molecules 25, no. 19: 4486.

Journal article
Published: 30 September 2020
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Knowledge of changes in macrophages following bacterial engulfment is limited. U937-derived macrophages were incubated with Staphylococcus aureus or Pseudomonas aeruginosa. Morphological and biochemical changes in macrophages following host-pathogen interactions were visualized using Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) respectively. Principal Component Analysis (PCA) was used to assess the variability in the FTIR spectra. Following host-pathogen interactions, survival of S. aureus was significantly lower than P. aeruginosa (P 99 % of variability in the FTIR spectra explained by the first two principal components. These findings demonstrated that there were clear morphological and biochemical changes in macrophages following engulfment of two different bacterial types suggesting that the biochemical components of the bacterial cell wall influenced the biochemical characteristics and hence the morphology of macrophages in distinct ways.

ACS Style

Mohamed El Mohtadi; Lisa Pilkington; Christopher M. Liauw; Jason J. Ashworth; Nina Dempsey-Hibbert; Amina Belboul; Kathryn A. Whitehead. Differential engulfment of Staphylococcus aureus and Pseudomonas aeruginosa by monocyte-derived macrophages is associated with altered phagocyte biochemistry and morphology. 2020, 19, 1372 -1384.

AMA Style

Mohamed El Mohtadi, Lisa Pilkington, Christopher M. Liauw, Jason J. Ashworth, Nina Dempsey-Hibbert, Amina Belboul, Kathryn A. Whitehead. Differential engulfment of Staphylococcus aureus and Pseudomonas aeruginosa by monocyte-derived macrophages is associated with altered phagocyte biochemistry and morphology. . 2020; 19 ():1372-1384.

Chicago/Turabian Style

Mohamed El Mohtadi; Lisa Pilkington; Christopher M. Liauw; Jason J. Ashworth; Nina Dempsey-Hibbert; Amina Belboul; Kathryn A. Whitehead. 2020. "Differential engulfment of Staphylococcus aureus and Pseudomonas aeruginosa by monocyte-derived macrophages is associated with altered phagocyte biochemistry and morphology." 19, no. : 1372-1384.

Research article
Published: 17 June 2020 in The Journal of Physical Chemistry C
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Additive manufacturing (AM) provides a unique platform for the rapid design and fabrication of complex structures. Printed structures can be used as is or as templates to be decorated with electrochemically deposited nanomaterials, which may be utilized as electrocatalytic sensing platforms. Novel methods are required to determine the electrochemical deposition morphology present on the electrode surfaces. Additively manufactured graphene macroelectrodes (AM-GMs) were fabricated using a commercially available feedstock and molybdenum dioxide (MoO2) was successfully electrochemically deposited onto the electrode surface. The electrochemically deposited MoO2 was analyzed using scanning electron microscopy (SEM), optical interferometry, Raman spectroscopy, and multifractal analysis (MFA). Although the electrochemical deposition of MoO2 nanowires was clearly visible using SEM, MFA enabled quantification of the MoO2 nanowires deposited at various time points (20–300 s). MFA was utilized to generate quantitative data, derived from f(α) curves, to determine the area of the electrochemically deposited MoO2 nanowires, including coverage, density, dispersion, and clustering. The AM-GMs, which were subjected to 300 s (maximum time period) of MoO2 electrodeposition, demonstrated the greatest percentage area coverage (20.14%). The use of such mathematical systems offers an inexpensive method to characterize the parameters of electrochemically deposited materials.

ACS Style

Anthony Slate; Kathryn A. Whitehead; Stephen Lynch; Christopher W. Foster; Craig E. Banks. Electrochemical Decoration of Additively Manufactured Graphene Macroelectrodes with MoO2 Nanowires: An Approach to Demonstrate the Surface Morphology. The Journal of Physical Chemistry C 2020, 124, 1 .

AMA Style

Anthony Slate, Kathryn A. Whitehead, Stephen Lynch, Christopher W. Foster, Craig E. Banks. Electrochemical Decoration of Additively Manufactured Graphene Macroelectrodes with MoO2 Nanowires: An Approach to Demonstrate the Surface Morphology. The Journal of Physical Chemistry C. 2020; 124 (28):1.

Chicago/Turabian Style

Anthony Slate; Kathryn A. Whitehead; Stephen Lynch; Christopher W. Foster; Craig E. Banks. 2020. "Electrochemical Decoration of Additively Manufactured Graphene Macroelectrodes with MoO2 Nanowires: An Approach to Demonstrate the Surface Morphology." The Journal of Physical Chemistry C 124, no. 28: 1.

Research article
Published: 14 April 2020 in ACS Applied Materials & Interfaces
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The reduction of bacteria and biofilm formation is important when designing surfaces for use in industry. Molybdenum disulphide surfaces (MoS2SUR) were produced using MoS2 particle (MoS2PAR) sizes of 90 nm 2 µm and 6 µm containing MoS2PAR concentrations of 5%, 10%, 15% and 20%. These were tested to determine the efficacy of the MoS2SUR to impede bacterial retention and biofilm formation of two different types of bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. The MoS2SUR were characterised using Fourier Transform InfraRed Spectroscopy, Ion Coupled Plasma Atomic Emission Spectroscopy, Scanning Electron Microscopy, Optical Profilometry and Water Contact Angles. The MoS2SUR made with the smaller 90 nm MoS2PAR sizes demonstrated smaller topographical shaped features. As the size of the incorporated MoS2PAR increased, the MoS2SUR demonstrated wider surface features, and they were less wettable. The increase in MoS2PAR concentration within the MoS2SUR groups did not affect the surface topography but did increase wettability. However, the increase in MoS2PAR size increased both the surface topography and wettability. The MoS2SUR with the smaller topographical shaped features, influenced the retention of the S. aureus bacteria. Increased MoS2SUR topography and wettability resulted in the greatest reduction in bacterial retention and the bacteria became more heterogeneously dispersed and less clustered across the surfaces. The surfaces that exhibited decreased bacterial retention (largest particle sizes, largest features, greatest roughness, most wettable) resulted in decreased biofilm formation. Cytotoxicity testing of the surface using cell viability demonstrated that the MoS2SUR were not toxic against HK-2 cells at MoS2PAR sizes of 90 nm and 2 µm. This work demonstrated that individual surfaces variables (MoS2SUR topographic shape and roughness, MoS2PAR size and concentration) decreased bacterial loading on the surfaces, which then decreased biofilm formation. By optimising MoS2SUR properties, it was possible to impede bacterial retention and subsequent biofilm formation.

ACS Style

Mohsin Amin; Samuel James Rowley-Neale; Liliana Shalamanova; Stephen Lynch; Joels T. Wilson-Nieuwenhuis; Mohamed El Mohtadi; Craig E. Banks; Kathryn A. Whitehead. Molybdenum Disulfide Surfaces to Reduce Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation. ACS Applied Materials & Interfaces 2020, 12, 21057 -21069.

AMA Style

Mohsin Amin, Samuel James Rowley-Neale, Liliana Shalamanova, Stephen Lynch, Joels T. Wilson-Nieuwenhuis, Mohamed El Mohtadi, Craig E. Banks, Kathryn A. Whitehead. Molybdenum Disulfide Surfaces to Reduce Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation. ACS Applied Materials & Interfaces. 2020; 12 (18):21057-21069.

Chicago/Turabian Style

Mohsin Amin; Samuel James Rowley-Neale; Liliana Shalamanova; Stephen Lynch; Joels T. Wilson-Nieuwenhuis; Mohamed El Mohtadi; Craig E. Banks; Kathryn A. Whitehead. 2020. "Molybdenum Disulfide Surfaces to Reduce Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation." ACS Applied Materials & Interfaces 12, no. 18: 21057-21069.

Original paper
Published: 14 March 2020 in Journal of Polymers and the Environment
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Biofouling of PVAc and PVOH surfaces by fungal conidia can result in surface discolouration and subsequent biodeterioration. In order to understand the interactions of fungal conidia on polymer surfaces, the surface properties of PVAc and PVOH and the hydrophobicity, size and shape of three type of fungal conidia was determined (Aspergillus niger 1957, Aspergillus niger 1988 and Aureobasidium pullulans). Fungal conidia were used in a range of binding assays (attachment, adhesion and retention). The PVAc and PVOH demonstrated different surface topographies and the PVAc demonstrated a higher maximum height (300.6 nm) when compared to the PVOH (434.2 nm). The PVAc surfaces was less wettable (75°) than the PVOH surface (62°). The FTIR demonstrated differences in the chemistries of the two surfaces, whereby the PVOH confirmed the presence of polar moieties. Hydrophobicity assays demonstrated that both A. niger species’ were more non-wettable than the A. pullulans. Following the attachment assays, the more hydrophobic Aspergillus spp. conidia attached in greater numbers to the more wettable surface and the A. pullulans was retained in greater numbers to the less wettable PVAc surface. The adhesion and retention assays demonstrated that the more polar surface retained all the types of conidia, regardless of their surface hydrophobicities. This study demonstrated that conidial binding to the surfaces were influenced by the chemistry and physicochemistry of the surfaces and spores. However, the inclusion of a washing stage influenced the adhesion of conidia to surfaces. In environments that were indicative of a attachment or retention assay a PVAc surface would reduce the number of A. niger spp. spores whilst a PVOH surface would reduce the number of A. pullulans spores. However, in an environment similar to a adhesion assay, a PVAc surface would be most beneficial to reduce spore retention. Thus, the use of the correct methodology that reflects the environment in which the surface is to be used is important in order to accurately inform hygienic surface development.

ACS Style

Christopher M. Liauw; Anthony Slate; Jonathan Butler; Joels Wilson-Nieuwenhuis; Ted Deisenroth; Andrea Preuss; Joanna Verran; Kathryn A. Whitehead. The Effect of Surface Hydrophobicity on the Attachment of Fungal Conidia to Substrates of Polyvinyl Acetate and Polyvinyl Alcohol. Journal of Polymers and the Environment 2020, 28, 1450 -1464.

AMA Style

Christopher M. Liauw, Anthony Slate, Jonathan Butler, Joels Wilson-Nieuwenhuis, Ted Deisenroth, Andrea Preuss, Joanna Verran, Kathryn A. Whitehead. The Effect of Surface Hydrophobicity on the Attachment of Fungal Conidia to Substrates of Polyvinyl Acetate and Polyvinyl Alcohol. Journal of Polymers and the Environment. 2020; 28 (5):1450-1464.

Chicago/Turabian Style

Christopher M. Liauw; Anthony Slate; Jonathan Butler; Joels Wilson-Nieuwenhuis; Ted Deisenroth; Andrea Preuss; Joanna Verran; Kathryn A. Whitehead. 2020. "The Effect of Surface Hydrophobicity on the Attachment of Fungal Conidia to Substrates of Polyvinyl Acetate and Polyvinyl Alcohol." Journal of Polymers and the Environment 28, no. 5: 1450-1464.

Journal article
Published: 06 February 2020 in Microorganisms
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Candida spp. are the most prevalent fungi of the human microbiota and are opportunistic pathogens that can cause oral candidiasis. Management of such infections is limited due to the low number of antifungal drugs available, their relatively high toxicity and the emergence of antifungal resistance. Therefore, much interest in the antimicrobial potential of natural compounds has recently been evident. The use of hydrogels in the delivery of biocides has been explored due to their biocompatibility, ease with drug encapsulation, and due to their potential to confer mechanical and structural properties similar to biological tissue. Methylcellulose hydrogels (10% (w/v)) with 1% (v/v) and 2% (v/v) Melissa officinalis oil were synthesised. The rheological properties and gelation time of the hydrogels were evaluated. Antimicrobial action, the antifungal potential and ability to displace Candida were determined. Rheological tests revealed that the hydrogel jellified in three minutes at 37 °C. Loaded hydrogels successfully inhibited Candida albicans growth as evident by zone of inhibition and time-kill assays. A significant reduction in retained C. albicans was demonstrated with the hydrogel at 2% Melissa officinalis concentration. This work demonstrated that an essential oil-loaded hydrogel had the potential to provide a novel antimicrobial therapy for the treatment of oral candidiasis.

ACS Style

Elisa Serra; Fabien Saubade; Cosimo Ligorio; Kathryn Whitehead; Alastair Sloan; David W. Williams; Araida Hidalgo-Bastida; Joanna Verran; Sladjana Malic. Methylcellulose Hydrogel with Melissa officinalis Essential Oil as a Potential Treatment for Oral Candidiasis. Microorganisms 2020, 8, 215 .

AMA Style

Elisa Serra, Fabien Saubade, Cosimo Ligorio, Kathryn Whitehead, Alastair Sloan, David W. Williams, Araida Hidalgo-Bastida, Joanna Verran, Sladjana Malic. Methylcellulose Hydrogel with Melissa officinalis Essential Oil as a Potential Treatment for Oral Candidiasis. Microorganisms. 2020; 8 (2):215.

Chicago/Turabian Style

Elisa Serra; Fabien Saubade; Cosimo Ligorio; Kathryn Whitehead; Alastair Sloan; David W. Williams; Araida Hidalgo-Bastida; Joanna Verran; Sladjana Malic. 2020. "Methylcellulose Hydrogel with Melissa officinalis Essential Oil as a Potential Treatment for Oral Candidiasis." Microorganisms 8, no. 2: 215.

Original paper
Published: 08 January 2020 in Archives of Microbiology
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Burn infections caused by Pseudomonas aeruginosa pose a major complication in wound healing. This study aimed to determine the antimicrobial effect of metal ions, graphene (Gr), and graphene oxide (GO), individually and in combination, against the planktonic and biofilm states of two antimicrobially resistant clinical strains of P. aeruginosa each with different antibiotic resistance profiles. Minimum inhibitory, minimum bactericidal, and fractional inhibitory concentrations were performed to determine the efficacy of the metal ions and graphene composites individually and their synergy in combination. Crystal violet biofilm and XTT assays measured the biofilm inhibition and metabolic activity, respectively. Molybdenum, platinum, tin, gold, and palladium ions exhibited the greatest antimicrobial activity (MIC = 7.8–26.0 mg/L), whilst GO and Gr demonstrated moderate-to-no effect against the planktonic bacterial cells, irrespective of their antibiograms. Biofilms were inhibited by zinc, palladium, silver, and graphene. In combination, silver–graphene and molybdenum–graphene inhibited both the planktonic and biofilm forms of the bacteria making them potential candidates for development into topical antimicrobials for burns patients infected with antibiotic-resistant P. aeruginosa.

ACS Style

Nathalie Karaky; Andrew Kirby; Andrew McBain; Jonathan Butler; Mohamed El Mohtadi; Craig E. Banks; Kathryn A. Whitehead. Metal ions and graphene-based compounds as alternative treatment options for burn wounds infected by antibiotic-resistant Pseudomonas aeruginosa. Archives of Microbiology 2020, 202, 995 -1004.

AMA Style

Nathalie Karaky, Andrew Kirby, Andrew McBain, Jonathan Butler, Mohamed El Mohtadi, Craig E. Banks, Kathryn A. Whitehead. Metal ions and graphene-based compounds as alternative treatment options for burn wounds infected by antibiotic-resistant Pseudomonas aeruginosa. Archives of Microbiology. 2020; 202 (5):995-1004.

Chicago/Turabian Style

Nathalie Karaky; Andrew Kirby; Andrew McBain; Jonathan Butler; Mohamed El Mohtadi; Craig E. Banks; Kathryn A. Whitehead. 2020. "Metal ions and graphene-based compounds as alternative treatment options for burn wounds infected by antibiotic-resistant Pseudomonas aeruginosa." Archives of Microbiology 202, no. 5: 995-1004.