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332 results on '"Jenkins, A Toby A"'

7. On-demand release of silver from composite hydrogel by cold atmospheric plasma jet for wound infection control

Author

Thet, Naing Tun, Patenall, Bethany L., Short, Robert D., Jenkins, A. Toby A., Thet, Naing Tun, Patenall, Bethany L., Short, Robert D., and Jenkins, A. Toby A.

Abstract

Silver is an antimicrobial commonly used within wound care chiefly in advanced dressings or in a topical cream form, such as silver sulfadiazine (SSD). Although silver is effective at controlling the growth of many common wound bacteria, it can be cytotoxic and can build up in tissue, stalling the healing process. Here, we demonstrate the development of an on-demand release system for delivery of silver from a composite hydrogel comprising sodium polyacrylate particles dispersed in a cryo-crosslinked polyvinyl alcohol carrier gel. Application of cold atmospheric plasma (CAP) jet to the silver loaded hydrogel resulted in controlled release of silver. This release is thought to occur due to the formation of nitrous acids in the hydrogel by the CAP, resulting in protonation of carboxylate groups in the hydrogel and subsequent gel de-swelling due to the reduction in interchain charge repulsion. The location of silver within the sodium polyacrylate particles was probed using scanning electron microscopy and EDX imaging. The released silver inhibited the growth of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus and significantly reduced the viable cell count of the P. aeruginosa biofilm.

Published
2024

8. Detecting and monitoring incontinence associated dermatitis: Does impedance spectroscopy have a part to play?

Author

Owen, Emily J, Heylen, Rachel A, Stewart, Kyle, Winyard, Paul G, and Jenkins, A Toby A

Abstract

In this review, current understanding of the prevention and treatment of Incontinence Associated Dermatitis (IAD) is discussed. The need for preventative measures which target specific faecal/urinary irritants is highlighted, including the role of urease inhibitors. There is no existing internationally and clinically accepted method to diagnose and categorise the severity of IAD. Diagnosis currently relies on visual inspection; non-invasive techniques to assess skin barrier function could remove subjectiveness, particularly in darker skin tones. Impedance spectroscopy is a non-invasive technique which can be used to monitor skin barrier function, supporting visual assessments. Six studies (2003–2021) which used impedance to assess dermatitis were reviewed; inflamed skin was distinguishable from healthy skin in each case. This suggests that impedance spectroscopy could be useful in diagnosis early-stage IAD, potentially enabling earlier intervention. Finally, the authors present their initial findings on the role of urease in skin breakdown in an in vivo IAD model, using impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Rational design and in vitrotesting of new urease inhibitors to prevent urinary catheter blockageElectronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4md00378k

Author

Heylen, Rachel A., Cusick, Nicola, White, Tom, Owen, Emily J., Patenall, Bethany L., Alm, Martin, Thomsen, Peter, Laabei, Maisem, and Jenkins, A. Toby A.

Abstract

Catheter associated urinary tract infections (CAUTI) caused by urease-positive organisms can lead to catheter blockage: urease metabolizes urea in urine to ammonia causing an increase in pH and hence precipitation of struvite and apatite salts into the catheter lumen and bladder leading to blockage. Acetohydroxamic acid (AHA) is the only urease inhibitor currently approved for patient use, however, it is rarely used owing to its side effects. Here, we report the identification and development of new urease inhibitors discovered using a rational in silicodrug design approach. A series of compounds were designed, the compounds were screened and filtered to identify three compounds which were tested in in vitrourease activity assays. N,N′-Bis(3-pyridinylmethyl)thiourea (Bis-TU) outperformed AHA in activity assays and was tested in an in vitrobladder model, where it significantly extended the lifetime of the catheter compared to AHA. Bis-TU was delivered viaa diffusible balloon catheter directly to the site of activity, thus demonstrating localized drug delivery. This cost-effective drug design approach allowed the identification of a potent urease inhibitor, which could be improved through iterative repeats of the method, and the process of design could be utilized to target other diseases.

Published
2024
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22. Controlling the structure of supramolecular fibre formation for benzothiazole based hydrogels with antimicrobial activity against methicillin resistant Staphylococcus aureus

Author

Hilton, Kira lLeighanne Frances, primary, Karamalegkos, Antonis A, additional, Allen, Nyasha, additional, Gwynne, Lauren, additional, Streather, Bree, additional, White, Lisa J., additional, Baker, Karen B, additional, Henry, Samantha A, additional, Williams, George, additional, Shepherd, Helena Jane, additional, Shepherd, Mark, additional, Hind, Charlotte K, additional, Sutton, J. Mark, additional, Jenkins, A. Toby, additional, Mulvihill, Daniel P, additional, Tullet, Jennifer, additional, Ezcurra, Marina, additional, and Hiscock, Jennifer Ruth, additional

Published
2023
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25. A TCF-based fluorescent probe to determine nitroreductase (NTR) activity for a broad-spectrum of bacterial species.

Author

Yan, Kai-Cheng, Gardiner, Jordan E., Sedgwick, Adam C., Thet, Naing, Heylen, Rachel A., James, Tony D., Jenkins, A. Toby A., and He, Xiao-Peng

Subjects
FLUORESCENT probes, BACTERIAL growth, SPECIES, BIOFILMS
Abstract

A nitroreductase (NTR) responsive fluorescent probe with long wavelength fluorescence emission was used to determine the NTR activity of a selection of bacterial species under a range of different bacterial growth conditions ensuring applicability under multiple complex clinical environments, where sensitivity, reaction time, and the detection accuracy were suitable for planktonic cultures and biofilms. [ABSTRACT FROM AUTHOR]

Published
2023
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26. On Plasma Activated Acetyl Donors:Comparing the Antibacterial Efficacy of Tetraacetylethylenediamine and Pentaacetate Glucose

Author

Starikovskiy, Andrey, Szili, Endre J., Patenall, Bethany L., Fellows, Adrian, Mistry, Dharmit, Jenkins, A. Toby A., Short, Robert D., Ghimire, Bhagirath, Starikovskiy, Andrey, Szili, Endre J., Patenall, Bethany L., Fellows, Adrian, Mistry, Dharmit, Jenkins, A. Toby A., Short, Robert D., and Ghimire, Bhagirath

Abstract

The study compares how acetyl donor molecules tetraacetylethylenediamine (TAED) and pentaacetate glucose (PAG) improve the antibacterial efficacy of solutions activated with a low-temperature atmospheric-pressure argon plasma jet. Plasma activation of solubilised TAED and PAG produce solutions with different chemical compositions and oxidative potentials. Both acetyl donor molecules enhance the hydrogen peroxide (H2O2) concentration in solution with TAED being more effective compared to PAG. However, PAG is more effective at forming peracetic acid (PAA) from reaction of its acetyl donor groups with plasma generated H2O2. The enhanced oxidative potential of plasma activated TAED and PAG solutions were shown to significantly improve bactericidal activity against common wound pathogens Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus compared to plasma activated water produced without acetyl donors. Furthermore, the oxidative capacity of plasma activated PAG was least affected by the bacterial oxidative defence enzyme catalase, attributed to the high concentration of PAA produced in this formulation. Overall, the above data show that acetyl donors may help improve next generation of antimicrobial formulations produced by plasma, which might help combat increasing problems of antimicrobial resistance.

Published
2022

30. The influence of a second ground electrode on hydrogen peroxide production from an atmospheric pressure argon plasma jet and correlation to antibacterial efficacy and mammalian cell cytotoxicity

Author

Ghimire, Bhagirath, primary, Patenall, Bethany L, additional, Szili, Endre J, additional, Gaur, Nishtha, additional, Lamichhane, Pradeep, additional, Thet, Naing T, additional, Trivedi, Dhruv, additional, Jenkins, Andrew Toby A, additional, and Short, Robert D, additional

Published
2021
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36. Enhancement of hydrogen peroxide production from an atmospheric pressure argon plasma jet and implications to the antibacterial activity of plasma activated water

Author

Ghimire, Bhagirath, primary, Szili, Endre J, additional, Patenall, Bethany L, additional, Lamichhane, Pradeep, additional, Gaur, Nishtha, additional, Robson, Alexander J, additional, Trivedi, Dhruv, additional, Thet, Naing T, additional, Jenkins, A Toby A, additional, Choi, Eun Ha, additional, and Short, Robert D, additional

Published
2021
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38. Long-wavelength TCF-based fluorescence probes for the detection and intracellular imaging of biological thiols† †Electronic supplementary information (ESI) available: All data supporting this study. See DOI: 10.1039/c8cc01661e

Author

Sedgwick, Adam C., Gardiner, Jordan E., Kim, Gyoungmi, Yevglevskis, Maksims, Lloyd, Matthew D., Jenkins, A. Toby A., Bull, Steven D., Yoon, Juyoung, and James, Tony D.

Subjects
Chemistry, Nitriles, Humans, Cysteine, Hydrogen Peroxide, Cisplatin, Furans, Glutathione, Homocysteine, Fluorescence, Fluorescent Dyes, HeLa Cells, Molecular Imaging
Abstract

Two ‘turn on’ TCF-based fluorescence probes were developed for the detection of biological thiols (TCF-GSH and TCFCl-GSH)., Two ‘turn on’ TCF-based fluorescence probes were developed for the detection of biological thiols (TCF-GSH and TCFCl-GSH). TCF-GSH was shown to have a high sensitivity towards glutathione (GSH) with a 0.28 μM limit of detection. Unfortunately, at higher GSH concentrations the fluorescence intensity of TCF-GSH decreased and toxicity was observed for TCF-GSH in live cells. However, TCFCl-GSH was shown to be able to detect GSH at biologically relevant concentrations with a 0.45 μM limit of detection. No toxicity was found for TCFCl-GSH and a clear ‘turn on’ with good photostability was observed for the exogenous addition of GSH, Cys and HCys. Furthermore, TCFCl-GSH was used to evaluate the effects of drug treatment on the levels of GSH in live cells.

Published
2018

39. The Evaluation of Ester Functionalised TCF‐Based Fluorescent Probes for the Detection of Bacterial Species

Author

Gwynne, Lauren, primary, Williams, George T., additional, Yan, Kai‐Cheng, additional, Gardiner, Jordan E., additional, Hilton, Kira L. F., additional, Patenall, Bethany L., additional, Hiscock, Jennifer R., additional, Maillard, Jean‐Yves, additional, He, Xiao‐Peng, additional, James, Tony D., additional, Sedgwick, Adam C., additional, and Jenkins, A. Toby A., additional

Published
2021
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42. Surface plasmon fluorescence measurements of human chorionic gonadotrophin: role of antibody orientation in obtaining enhanced sensitivity and limit of detection

Author

Vareiro, Margarida M.L.M., Liu, Jing, Knoll, Wolfgang, Zak, Kris, Williams, David, and Jenkins, A. Toby A.

Subjects
Chorionic gonadotropin -- Research, Chemistry, Analytic -- Research, Antibodies -- Research, Viral antibodies -- Research, Chemistry
Abstract

This paper describes the determination of limits of detection (LODs) of interactions between an antigen, human chorionic gonadotrophin (hCG), and antibodies, anti-[alpha]-hCG and anti-[beta]-hCG, using a sandwich assay by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). Randomly biotinylated antibodies were adsorbed onto a structured self-assembled monolayer (SAM)--streptavidin matrix, tethered to gold via a SAM consisting of biotinylated thiol molecules interspersed with hydroxyalkanethiol molecules. The influence of the concentration of biotinylated thiol on the binding of biotinylated antibody and its functionality, in terms of its ability to bind to the hCG antigen, was studied. This allowed determination of the optimum biotin--thiol mole fraction in the mixed thiol solution and consequently in the SAM, to maximize binding of hCG of the streptavidin-bound antibody. SPFS studies of the binding of a secondary fluorescently labeled antibody to hCG immobilized on the optimized SAM--streptavidin--antibody layer showed that a LOD of hCG of 2 mIU [mL.sup.-1] (4 x [10.sup.-12] mol [L.sup.-1]) could be realized. The system was further optimized by using a more oriented and organized surface by adsorbing monobiotinylated Fab--hCG in place of the whole antibody. A LOD of 0.3 mIU [mL.sup.-1] (6 x [10.sup.-13] mol [L.sup.-1]) was achieved for this system. This work illustrates the importance of antibody orientation, both on the planar surface and in terms of position of binding site, in maximizing sensor sensitivity.

Published
2005

45. Protein Encapsulation: A Nanocarrier Approach to the Fluorescence Imaging of an Enzyme-Based Biomarker

Author

Jia, Zhiyuan, primary, Han, Hai-Hao, additional, Sedgwick, Adam C., additional, Williams, George T., additional, Gwynne, Lauren, additional, Brewster, James T., additional, Bull, Steven D., additional, Jenkins, A. Toby A., additional, He, Xiao-Peng, additional, Schönherr, Holger, additional, Sessler, Jonathan L., additional, and James, Tony D., additional

Published
2020
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48. Microcontact printing of lipophilic self-assembled monolayers for the attachment of biomimetic lipid bilayers to surfaces

Author

Jenkins, A. Toby. A., Boden, Neville, Bushby, Richard J., Evans, Stephen. D., Knowles, Peter F., Miles, Robert E., Ogier, Simon. D., Schonherr, Holger, and Vancso, G. Julius

Subjects
Bilayer lipid membranes -- Research, Biomimetics -- Case studies, Biosensors -- Research, Monomolecular films -- Research, Chemistry
Abstract

A study demonstrates the use of the micro-patterning of thiol-terminated lipophilic self-assembled monolayers to support planar lipid bilayer membranes which satisfy the critical criteria required for use as potential biosensors. This new method involving the integration of microcontact printing and self-assembly of lipid vesicles enables the construction of a tethered biomimetic membrane. Experimental methods and results are discussed.

Published
1999

50. Dye Displacement Assay for Saccharides using Benzoxaborole Hydrogels

Author

Lampard, Emma V., Sedgwick, Adam C., Sombuttan, Thitima, Williams, George T., Wannalerse, Boontana, Jenkins, A. Toby A., Bull, Steven D., and James, Tony D.

Subjects
boronic acids, Communication, colorimetric detection, dye displacement assays, glucose, saccharides, Communications
Abstract

Dye displacement assays are a simple but effective method to determine the concentration of target analytes. Previously, we have shown that phenylboronic acid pinacol ester hydrogels (borogels) can be used to develop a boronic acid–Alizarin red S dye displacement assay for the determination of fructose (orange to red). In this work, benzoxaborole hydrogels (BOBgels) were developed, and these BOBgels demonstrated an enhanced apparent binding affinity towards monosaccharides, in particular towards glucose.

Published
2018

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