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Journal of Food Composition and Analysis (10960481)147
Meat adulteration is a critical issue affecting food safety, public health, and regulatory compliance. The lower cost and wide availability of poultry compared to mammalian meat increase the risk of fraudulent substitution in processed products. To address this, a rapid and reliable Loop-Mediated Isothermal Amplification (LAMP) assay was developed to detect several common avian meat species in raw and heat- and pressure-treated samples. Conserved regions of the glyceraldehyde-3-phosphate dehydrogenase (gapdh) gene were targeted to design a LAMP primer set specific to avian species. To assess the assay's performance, six common avian species (chicken, turkey, goose, duck, ostrich, quail) and four non-avian species (sheep, cattle, goat, camel) were tested. DNA was extracted using a salt-based method, and the assay's specificity and sensitivity were evaluated on raw, cooked, and autoclaved samples. The LAMP assay successfully detected chicken, turkey, goose, and duck DNA. The detection limit of 110 femtograms was established for chicken DNA. In chicken–beef mixtures, as little as 0.1 % chicken in raw and cooked samples and 1 % in autoclaved samples was identified. The method detected avian DNA in under an hour using minimal equipment. Its simplicity, speed, and robustness make it an effective tool for detecting avian meat, supporting food fraud prevention and accurate labeling. © 2025 Elsevier Inc.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy (13861425)304
Fast and accurate detection of antimicrobial resistance in pathogens remains a challenge, and with the increase in antimicrobial resistance due to mis- and overuse of antibiotics, it has become an urgent public health problem. We demonstrate how infrared attenuated total reflection (IR-ATR) can be used as a simple method for assessment of bacterial susceptibility to antibiotics. This is achieved by monitoring the metabolic activities of bacterial cells via nutrient consumption and using this as an indicator of bacterial viability. Principal component analysis of the obtained spectra provides a tool for fast and simple discrimination of antimicrobial resistance in the acquired data. We demonstrate this concept using four bacterial strains and four different antibiotics, showing that the change in glucose concentration in the growth medium after 2 h, as monitored by IR-ATR, can be used as a spectroscopic diagnostic technique, to reduce detection time and to improve quality in the assessment of antimicrobial resistance in pathogens. © 2023 The Author(s)
Nguyen, T.,
Vinayaka, A.C.,
Huynh, V.N.,
Linh, Q.T.,
Andreasen, S.Z.,
Glaby, M.,
Bang, D.D.,
Møller, J.K.,
Wolff, A. Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) (10846999)2023pp. 437-439
In the ongoing COVID-19 pandemic, sensitive and rapid on-site detection of the SARS-CoV-2 coronavirus has been one of crucial objectives. A point-of-care (PoC) device called PATHPOD for quick, on-site detection of SARS-CoV-2 employing a real-time reverse-transcription loop-mediated isothermal amplification (RT-rLAMP) reaction on a polymer cartridge. The PATHPOD consists of a standalone device (weighing under 1.2 kg) and a cartridge, and can identify 10 distinct samples and 2 controls in less than 50 minutes. The PATHPOD PoC system is fabricated and clinically validated for the first time in this work © 2023 IEEE.
Vinayaka, A.C.,
Quyen, T.L.,
Glaby, M.,
Nguyen, T.,
Huynh, V.N.,
Bang, D.D.,
Wolff, A. pp. 79-106
Trends in adapting new-generation biosensors for rapid detection of infectious diseases are gaining interest in the field of clinical diagnostics and point-of-care (POC) industry. Advanced molecular amplification techniques, next-generation affinity probes such as aptamers, and unique optical features of nanoparticles such as quantum dots, graphene, palladium, silver, and gold nanoparticles have significant impact on the development of such biosensors. Among several nucleic acid amplification techniques, loop-mediated isothermal amplification (LAMP) has proven to be a promising technique for rapid online detection because of its unique features that suit ideal for POC applications. Similarly, aptamers have widespread applications in the POC industry as they provide remarkable flexibility and convenience in engineering the desired structures. POC biosensor development primarily relies on precise incorporation, integration, and streamlining of all the necessary steps from sample preparation to detection and analysis. Realizing high accuracy and sensitivity in a time-saving and cost-effective manner has always been the pre-requisite and customer interest. With this perspective, this book chapter details the most important factors that play a role in interfacing new-generation molecular techniques, the state-of-the-art sample preparation, and pathogen concentration strategies with robust sensing platforms for POC diagnostic applications. We will focus mainly on the principal factors governing analytical precision and robustness of new-generation molecular techniques such as direct PCR, solid-phase PCR (SP-PCR), and LAMP in POC biosensors for pathogen detection. The role of aptamers in pathogen concentration and LAMP as an ideal nucleic acid amplification technique for POC biosensor development has been given priority. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.
Nguyen, T.,
Vinayaka, A.C.,
Huynh, V.N.,
Linh, Q.T.,
Andreasen, S.Z.,
Glaby, M.,
Bang, D.D.,
Møller, J.K.,
Wolff, A. Sensors and Actuators B: Chemical (09254005)392
Sensitive and rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a vital goal in the ongoing COVID-19 pandemic. We present in this comprehensive work, for the first time, detailed fabrication and clinical validation of a point of care (PoC) device for rapid, onsite detection of SARS-CoV-2 using a real-time reverse-transcription loop-mediated isothermal amplification (RT-LAMP) reaction on a polymer cartridge. The PoC system, namely PATHPOD, consisting of a standalone device (weight less than 1.2 kg) and a cartridge, can perform the detection of 10 different samples and two controls in less than 50 min, which is much more rapid than the golden standard real-time reverse-transcription Polymerase Chain Reaction (RT-PCR), typically taking 16–48 h. The novel total internal reflection (TIR) scheme and the reactions inside the cartridge in the PoC device allow monitoring of the diagnostic results in real-time and onsite. The analytical sensitivity and specificity of the PoC test are comparable with the current RT-PCR, with a limit of detection (LOD) down to 30–50 viral genome copies. The robustness of the PATHPOD PoC system has been confirmed by analyzing 398 clinical samples initially examined in two hospitals in Denmark. The clinical sensitivity and specificity of these tests are discussed. © 2023 The Authors
Vinayaka, A.C.,
Huynh, V.N.,
Quyen, T.L.,
Nguyen, T.,
Glaby, M.,
Madsen, M.,
Bang, D.D.,
Wolff, A. Analytical Chemistry (15206882)95(34)pp. 12656-12663
Accurate and rapid detection of pathogens in foods of animal origin has been a critical part of the One Health Action Plan of the European Union (EU). Biosensors have the potential in bringing required technologies to accomplish this on the field, wherein loop-mediated isothermal amplification (LAMP) and lab-on-a-chip have proven to be ideal. We have developed a LAMP-based point-of-care (POC) device, the VETPOD, as a solution to the contemporary challenges in the rapid detection of Salmonella spp. The core technology in the VETPOD is a ready-to-use cartridge that included an injection-molded polymer chip with pyramid-shaped optical structures embedded within the chip. These pyramid-shaped optical structures direct the incident light, due to total internal reflection (TIR), through the reaction chambers to the phototransistor. The VETPOD was validated against the ISO 6579-1 reference method. A total of 310 samples were tested that included 180 Salmonella spiked samples in 6 different meat categories and 130 strains to determine the specificity. The overall results were satisfactory, wherein the VETPOD had an acceptable sensitivity (96.51%) compared to the reference (98.81%) and near perfect agreement with ISO 6579-1 with an overall Cohen’s kappa of 0.94. The relative level of detection (RLOD) for the VETPOD was 1.38 CFU/25 g that was found to be 1.17 times higher than the reference. The VETPOD showed 98% precision for inclusivity and 100% precision for the exclusivity samples. The VETPOD proved as a useful alternative to detect Salmonella spp. that can be adaptable to a broader spectrum of pathogens in future. © 2023 American Chemical Society.
Quyen, T.L.,
Vinayaka, A.C.,
Glaby, M.,
Ngoc, H.V.,
Bang, D.D.,
Wolff, A. Frontiers in Cellular and Infection Microbiology (22352988)12
Loop-mediated isothermal amplification (LAMP) is being used as a robust rapid diagnostic tool to prevent the transmission of infectious diseases. However, carryover contamination of LAMP-amplified products originating from previous tests has been a problem in LAMP-based bio-analytical assays. In this study, we developed a Cod-uracil-DNA-glycosylase real-time reverse transcriptase LAMP assay (Cod-UNG-rRT-LAMP) for the elimination of carryover contamination and the rapid detection of SARS-CoV-2 in point-of-care (POC) testing. Using the Cod-UNG-rRT-LAMP assay, the SARS-CoV-2 virus could be detected as low as 2 copies/µl (8 copies/reaction) within 45 min of amplification and 2.63 ± 0.17 pg (equivalent to 2.296 × 109 copies) of contaminants per reaction could be eliminated. Analysis of clinical SARS-CoV-2 samples using the Cod-UNG-rRT-LAMP assay showed an excellent agreement with a relative accuracy of 98.2%, sensitivity of 97.1%, and specificity of 95.2% in comparison to rRT-PCR. The results obtained in this study clearly demonstrate the feasibility of the use of the Cod-UNG-rRT-LAMP assay for applications toward the POC diagnosis of SARS-CoV-2 and on-site testing of other pathogens. Copyright © 2022 Quyen, Vinayaka, Golabi, Ngoc, Bang and Wolff.
Quyen, T.L.,
Vinayaka, A.C.,
Glaby, M.,
Nguyen, T.,
Ngoc, H.V.,
Bang, D.D.,
Wolff, A. Acs Sensors (23793694)7(11)pp. 3343-3351
Adaptations of new generation molecular techniques for multiplexed detection of pathogens are gaining interest in the field of point-of-care (POC) industry and onsite testing. Loop-mediated isothermal amplification (LAMP), an advanced molecular amplification technique, has proven promising due to its unique features that suits ideal for POC applications. However, application of LAMP for multiplexed detection of pathogens remains challenging because of the difficulty in the identification of specific LAMP amplicons that does not have a well-definite molecular size. In this study, we developed a solid-phase loop-mediated isothermal amplification (SP-LAMP) technique to address the challenge. Integration of LAMP with the supercritical angle fluorescence (SAF) micro-optic structures as a solid support (SS) in an array format enabled spatial separation of LAMP amplicons in a multiplexed configuration. Important parameters such as length of the SS primers, length of the primer-binding region, the effect of surface density of immobilized SS primers, and cross-reactivity among the primers of different targets were iteratively tested and optimized. With the combination of SP-LAMP and SAF techniques, it was possible to detect multiple pathogens that include Salmonella spp, Campylobater spp., Campylobacter coli, Campylobacter jejuni, avian influenza virus (AIV), and pan avian internal control (IC) under singleplex conditions. The multiplexing capacity of the SP-LAMP was demonstrated using AIV and IC with promising results. The success of SP-LAMP has opened a promising direction toward the development of a multiplex POC system for rapid detection of multiple pathogens. © 2022 American Chemical Society. All rights reserved.
Vinayaka, A.C.,
Glaby, M.,
Than, T.L.Q.,
Wolff, A.,
Bang, D.D. New Biotechnology (18716784)66pp. 1-7
Invasive non-typhoidal salmonellosis is gaining worldwide attention as an emerging disease cluster among bloodstream infections. The disease has the highest burden among immunocompromised and malnourished children in resource-limited areas due to poor access to reliable and rapid diagnostics. Point-of-care (POC) diagnostics are promising for use in such low infrastructure laboratory settings. However, there still remains a major challenge for POC testing to deal with the complexity of blood matrices in rapid detection of an extremely low concentration of blood-borne pathogens. In this work, the challenges were addressed by combining magnetic bead based pathogen concentration and Loop Mediated Isothermal Amplification (LAMP) technology. Sensitivity and performance of the combined approach were determined and compared with a direct PCR method. A direct visual detection strategy, adapted using SYTO-24 DNA intercalating dye, resulted in a limit of detection (LoD) as low as 14 CFU/mL in blood samples with a total analysis time of less than 2 h, including sample preparation. This approach has the potential for wide application as a high-throughput POC testing method to analyze pathogens in clinical, food, feed and environmental samples. © 2021 Elsevier B.V.
Glaby, M.,
Flodrops, M.,
Grasland, B.,
Vinayaka, A.C.,
Quyen, T.L.,
Nguyen, T.,
Bang, D.D.,
Wolff, A. Frontiers in Cellular and Infection Microbiology (22352988)11
Avian influenza virus (AIV) outbreaks occur frequently worldwide, causing a potential public health risk and great economic losses to poultry industries. Considering the high mutation rate and frequent genetic reassortment between segments in the genome of AIVs, emerging new strains are a real threat that may infect and spread through the human population, causing a pandemic. Therefore, rapid AIV diagnostic tests are essential tools for surveillance and assessing virus spreading. Real-time reverse transcription PCR (rRT-PCR), targeting the matrix gene, is the main official standard test for AIV detection, but the method requires well-equipped laboratories. Reverse transcription Loop-Mediated Isothermal Amplification (RT-LAMP) has been reported as a rapid method and an alternative to PCR in pathogen detection. The high mutation rate in the AIV genome increases the risk of false negative in nucleic acid amplification methods for detection, such as PCR and LAMP, due to possible mismatched priming. In this study, we analyzed 800 matrix gene sequences of newly isolated AIV in the EU and designed a highly efficient LAMP primer set that covers all AIV subtypes. The designed LAMP primer set was optimized in real-time RT-LAMP (rRT-LAMP) assay. The rRT-LAMP assay detected AIV samples belonging to nine various subtypes with the specificity and sensitivity comparable to the official standard rRT-PCR assay. Further, a two-color visual detection RT-LAMP assay protocol was adapted with the aim to develop on-site diagnostic tests. The on-site testing successfully detected spiked AIV in birds oropharyngeal and cloacal swabs samples at a concentration as low as 100.8 EID50 per reaction within 30 minutes including sample preparation. The results revealed a potential of this newly developed rRT-LAMP assay to detect AIV in complex samples using a simple heat treatment step without the need for RNA extraction. © Copyright © 2021 Golabi, Flodrops, Grasland, Vinayaka, Quyen, Nguyen, Bang and Wolff.
Dehghani, Z.,
Nguyen, T.,
Glaby, M.,
Hosseini, M.,
Rezayan, A.H.,
Mohammadnejad, J.,
Wolff, A.,
Vinayaka, A.C. Food Control (09567135)121
Concentration of pathogens directly from food samples by using magnetic beads is a potential strategy in the on-site food sample analysis. In this study, magnetic beads, double modified with platinum/palladium nanoparticle (Pt/Pd NP) and DNA aptamer, is presented as catalytic nano-bioprobes for the on-site detection of Salmonella enterica serovar Typhimurium in food and fecal samples. Combination of the developed catalytic nano-bioprobes with loop mediated isothermal amplification (LAMP) enabled rapid detection of low levels of S. Typhimurium in food and chicken fecal samples without culture enrichment. S. Typhimurium-specific DNA aptamer immobilized on the magnetic bead could efficiently concentrate S. Typhimurium with a capturing efficiency higher than 76% in phosphate-buffered saline (PBS). Further, DNA-mediated inhibition of peroxidase-mimic activity of Pt/Pd NP in combination with LAMP was used as a unique approach to detect S. Typhimurium. With this unique approach, it was possible to capture and detect S. Typhimurium as low as 10–15 CFU/mL in chicken meat sample and 3–10 CFU/mL in both whole egg and chicken fecal samples within less than 3 h. Analysis of S. Typhimurium-spiked chicken meat, whole egg and chicken fecal materials have confirmed the precision of the method. A relative accuracy of 90% with an intra and inter assay precision of 8.36% and 9.92% respectively was achieved in the S. Typhimurium-spiked food samples. This unique approach has the potential for the integration in to Lab-on-a-chip based biosensors for on-site monitoring of foodborne pathogens in future. © 2020
Nguyen, T.,
Vinayaka, A.C.,
Andreasen, S.Z.,
Glaby, M.,
Huynh, V.N.,
Linh, Q.T.,
Bang, D.D.,
Wolff, A. TrAC - Trends in Analytical Chemistry (01659936)131
The development of lab-on-a-chip technology and its applications in biochemical and biomedical analyses has, during the last two decades, led to the potential realisation of portable and on-site detection devices, the so-called point-of-care (PoC) detection systems. These are essentially cheap, easy-to-handle systems, offering rapid sample-to-answer results to non-technical operators. In this perspective, we do not review all the current advances of Lab-on-a-chip techniques for the realisation of PoC. Instead, we aim to provide insight into what we foresee as the three most important factors to play the essential roles for succeeding in making commercially viable PoC pathogen-detection devices. The three insights are namely: the utilizations of (i) disposable polymer (microfluidic) chips, (ii) the implementation of surface-bound (or solid-phase) nucleic-acid amplification techniques and (iii) relying (more) on open-source hardware and software. © 2020 The Author(s)
Glaby, M.,
Kuralay, F.,
Jager, E.W.,
Beni, V.,
Turner, A.P.F. Biosensors and Bioelectronics (18734235)93pp. 87-93
Biosensors can deliver the rapid bacterial detection that is needed in many fields including food safety, clinical diagnostics, biosafety and biosecurity. Whole-cell imprinted polymers have the potential to be applied as recognition elements in biosensors for selective bacterial detection. In this paper, we report on the use of 3-aminophenylboronic acid (3-APBA) for the electrochemical fabrication of a cell-imprinted polymer (CIP). The use of a monomer bearing a boronic acid group, with its ability to specifically interact with cis-diol, allowed the formation of a polymeric network presenting both morphological and chemical recognition abilities. A particularly beneficial feature of the proposed approach is the reversibility of the cis-diol-boronic group complex, which facilitates easy release of the captured bacterial cells and subsequent regeneration of the CIP. Staphylococcus epidermidis was used as the model target bacteria for the CIP and electrochemical impedance spectroscopy (EIS) was explored for the label-free detection of the target bacteria. The modified electrodes showed a linear response over the range of 103–107 cfu/mL. A selectivity study also showed that the CIP could discriminate its target from non-target bacteria having similar shape. The CIPs had high affinity and specificity for bacterial detection and provided a switchable interface for easy removal of bacterial cell. © 2016 Elsevier B.V.
Bagheryan, Z.,
Raoof, J.,
Glaby, M.,
Turner, A.P.F.,
Beni, V. Biosensors and Bioelectronics (18734235)80pp. 566-573
Fast and accurate detection of microorganisms is of key importance in clinical analysis and in food and water quality monitoring. Salmonella typhimurium is responsible for about a third of all cases of foodborne diseases and consequently, its fast detection is of great importance for ensuring the safety of foodstuffs.We report the development of a label-free impedimetric aptamer-based biosensor for S. typhimurium detection. The aptamer biosensor was fabricated by grafting a diazonium-supporting layer onto screen-printed carbon electrodes (SPEs), via electrochemical or chemical approaches, followed by chemical immobilisation of aminated-aptamer. FTIR-ATR, contact angle and electrochemical measurements were used to monitor the fabrication process. Results showed that electrochemical immobilisation of the diazonium-grafting layer allowed the formation of a denser aptamer layer, which resulted in higher sensitivity. The developed aptamer-biosensor responded linearly, on a logarithm scale, over the concentration range 1×101 to 1×108 CFU mL-1, with a limit of quantification (LOQ) of 1×101 CFU mL-1 and a limit of detection (LOD) of 6 CFU mL-1. Selectivity studies showed that the aptamer biosensor could discriminate S. typhimurium from 6 other model bacteria strains. Finally, recovery studies demonstrated its suitability for the detection of S. typhimurium in spiked (1×102, 1×104 and 1×106 CFU mL-1) apple juice samples. © 2016 Elsevier B.V.
Glaby, M.,
Padiolleau, L.,
Chen, X.,
Jafari, M.J.,
Sheikhzadeh, E.,
Turner, A.P.F.,
Jager, E.W.,
Beni, V. PLoS ONE (19326203)11(11)
Here we demonstrate the use of a functional dopant as a fast and simple way to tune the chemical affinity and selectivity of polypyrrole films. More specifically, a boronic-functionalised dopant, 4-N-Pentylphenylboronic Acid (PBA), was used to provide to polypyrrole films with enhanced affinity towards diols. In order to prove the proposed concept, two model systems were explored: (i) the capture and the electrochemical detection of dopamine and (ii) the adhesion of bacteria onto surfaces. The chemisensor, based on overoxidised polypyrrole boronic doped film, was shown to have the ability to capture and retain dopamine, thus improving its detection; furthermore the chemisensor showed better sensitivity in comparison with overoxidised perchlorate doped films. The adhesion of bacteria, Deinococcus proteolyticus, Escherichia coli, Streptococcus pneumoniae and Klebsiella pneumoniae, onto the boric doped polypyrrole film was also tested. The presence of the boronic group in the polypyrrole film was shown to favour the adhesion of sugar-rich bacterial cells when compared with a control film (Dodecyl benzenesulfonate (DBS) doped film) with similar morphological and physical properties. The presented single step synthesis approach is simple and fast, does not require the development and synthesis of functional monomers, and can be easily expanded to the electrochemical, and possibly chemical, fabrication of novel functional surfaces and interfaces with inherent pre-defined sensing and chemical properties. © 2016 Golabi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Journal of Biomedical Materials Research - Part A (15493296)104(9)pp. 2220-2233
Bacterial adhesion and subsequent biofilm formation on metals such as aluminum (Al) alloys lead to serious issues in biomedical and industrial fields from both an economical and health perspective. Here, we showed that a careful manipulation of Al surface characteristics via a facile two-steps superhydrophobic modification can provide not only biocompatibility and an ability to control protein adsorption and bacterial adhesion, but also address the issue of apparent long-term toxicity of Al-alloys. To find out the roles of surface characteristics, surface modification and protein adsorption on microbial adhesion and biofilm formation, the surfaces were systematically characterized by SEM, EDX, XPS, AFM, FTIR, water contact angle (WCA) goniometry, surface free energy (SFE) measurement, MTT, Bradford, Lowry and microtiter plate assays and also flow-cytometry and potentiostat analyses. Results showed that WCA and SFE changed from 70° to 163° and 36.3 to 0.13 mN m−1, respectively. The stable and durable modification led to a substantial reduction in static/dynamic BSA adsorption. The effect of such a treatment on the biofilm formation was analyzed by using three different bacteria of Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. The microtiter plate assay and flow cytometry analysis showed that the modification not only could substantially reduce the bacterial adhesion but this biofouling resistance is independent of bacterium type. An excellent cell viability after exposure of HeLa cells to waters incubated with the modified samples was observed. Finally, the corrosion rate reduced sharply from 856.6 to 0.119 MPY after superhydrophobic modifications, which is an excellent stable corrosion inhibition property. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2220–2233, 2016. © 2016 Wiley Periodicals, Inc.
Sensors and Actuators B: Chemical (09254005)222pp. 839-848
A novel rapid method for bacterial differentiation is explored based on the specific adhesion pattern of bacterial strains to tunable polymer surfaces. Different types of counter ions were used to electrochemically fabricate dissimilar polypyrrole (PPy) films with diverse physicochemical properties such as hydrophobicity, thickness and roughness. These were then modulated into three different oxidation states in each case. The dissimilar sets of conducting polymers were exposed to five different bacterial strains, Deinococcus proteolyticus, Serratia marcescens, Pseudomonas fluorescens, Alcaligenes faecalis and Staphylococcus epidermidis. By analysis of the fluorescent microscope images, the number of bacterial cells adhered to each surface were evaluated. Generally, the number of cells of a particular bacterial strain that adhered varied when exposed to dissimilar polymer surfaces, due to the effects of the surface properties of the polymer on bacterial attachment. Similarly, the number of cells that adhered varied with different bacterial strains exposed to the same surface, reflecting the different surface properties of the bacteria. Principal component analysis showed that each strain of bacteria had its own specific adhesion pattern. Hence, they could be discriminated by this simple, label-free method based on tunable polymer arrays combined with pattern recognition. © 2015 Elsevier B.V. All rights reserved.
Macromolecular Chemistry and Physics (10221352)217(10)pp. 1128-1135
Tuning the physical-chemical properties of polypyrrole (PPy) opens up potentially exciting new applications, especially in the area of bacterial adhesion. Polypyrrole is electrochemically synthesized under various conditions and the physical properties of the films and their effects on bacterial adhesion are characterized. Five types of dopants - chloride (Cl), perchlorate (ClO4), p-toluene-sulfonate (ToS), dodecylbenzene sulfonate (DBS), and poly sodium styrene sulfonate (PSS) - are used to fabricate PPy films at two different constant potentials (0.500 and 0.850 V) with and without Fe3+. Their thickness, roughness, and wettability are measured. The adhesion tendency of Escherichia coli, as a model bacterium, to the four polymers is studied. E. coli shows greater adhesion tendency to the hydrophobic, rough surface of PPy-DBS, and less adhesion tendency to the smooth and hydrophilic surface of PPy-PSS. The results facilitate the choice of appropriate electropolymerization conditions to modulate bacterial adhesion. Polypyrrole (PPy) is electrochemically synthesized under various conditions with different types of dopants to tune the surface properties of the film including roughness and hydrophobicity. The polymer surface properties show a significant effect on the bacterial adhesion to the surface. The results may guide choosing suitable polymer synthesis conditions to yield PPy with suitable surface properties for the intended application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Wibisono, Y.,
Yandi, W.,
Glaby, M.,
Nugraha, R.,
Cornelissen, E.,
Kemperman, A.J.,
Ederth, T.,
Nijmeijer, K. Water Research (00431354)71pp. 171-186
Biofouling is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a hydrogel-coated feed spacer and two-phase flow cleaning. Neutral (polyHEMA-co-PEG10MA), cationic (polyDMAEMA) and anionic (polySPMA) hydrogels have been successfully grafted onto polypropylene (PP) feed spacers via plasma-mediated UV-polymerization. These coatings maintained their chemical stability after 7 days incubation in neutral (pH 7), acidic (pH 5) and basic (pH 9) environments. Anti-biofouling properties of these coatings were evaluated by Escherichia coli attachment assay and nanofiltration experiments at a TMP of 600kPag using tap water with additional nutrients as feed and by using optical coherence tomography. Especially the anionic polySPMA-coated PP feed spacer shows reduced attachment of E. coli and biofouling in the spacer-filled narrow channels resulting in delayed biofilm growth. Employing this highly hydrophilic coating during removal of biofouling by two-phase flow cleaning also showed enhanced cleaning efficiency, feed channel pressure drop and flux recoveries. The strong hydrophilic nature and the presence of negative charge on polySPMA are most probably responsible for the improved antifouling behavior. A combination of polySPMA-coated PP feed spacers and two-phase flow cleaning therefore is promising and an environmentally friendly approach to control biofouling in NF/RO systems employing spiral-wound membrane modules. © 2015 Elsevier Ltd.
Ghaderi, A.,
De mayolo, E.A.,
Patra, H.K.,
Glaby, M.,
Parlak, O.,
Gunnarsson, R.,
Campos, R.,
Vishnu, R.,
Elhag, S.,
Subramanain, S. Advanced Materials Letters (discontinued) (09763961)6(2)pp. 87-98
Nanoscale theragnosis is the biomedical aspect of nanomaterials for simultaneous diagnosis and therapy. The last decade was completely devoted by the scientist to combine the advancement in nanotechnology molecular biotechnology for the development of future nanomedicine. The approach started with the development of target-specific delivery of the cargo imaging molecule or drugs for biomedical applications. The cutting edge advantages of the nanoscale materials (e.g., large surface to volume ratio, size-shape dependent physicochemical properties and multi-functionality etc) proved themselves as the most potential preferences to design optimal therapy for the personalized medicine. The present tutorial review will highlight the recent advances in the development on the regulation of such theragnosis system and their biomedical perspectives to act as a future nanomedicine. © 2015 VBRI Press.
Sharma, D.,
Ashaduzzaman, M.,
Glaby, M.,
Shriwastav, A.,
Bisetty, K.,
Tiwari, A. ACS Applied Materials and Interfaces (19448252)7(43)pp. 23848-23856
Molecular imprinting generates robust, efficient, and highly mesoporous surfaces for biointeractions. Mechanistic interfacial interaction between the surface of core substrate and protein corona is crucial to understand the substantial microbial toxic responses at a nanoscale. In this study, we have focused on the mechanistic interactions between synthesized saponin imprinted zinc oxide nanohoneycombs (SIZnO NHs), average size 80-125 nm, surface area 20.27 m2/g, average pore density 0.23 pore/nm and number-average pore size 3.74 nm and proteins corona of bacteria. The produced SIZnO NHs as potential antifungal and antibacterial agents have been studied on Sclerotium rolfsii (S. rolfsii), Pythium debarynum (P. debarynum) and Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), respectively. SIZnO NHs exhibited the highest antibacterial (∼50%) and antifungal (∼40%) activity against Gram-negative bacteria (E. coli) and fungus (P. debarynum), respectively at concentration of 0.1 mol. Scanning electron spectroscopy (SEM) observation showed that the ZnO NHs ruptured the cell wall of bacteria and internalized into the cell. The molecular docking studies were carried out using binding proteins present in the gram negative bacteria (lipopolysaccharide and lipocalin Blc) and gram positive bacteria (Staphylococcal Protein A, SpA). It was envisaged that the proteins present in the bacterial cell wall were found to interact and adsorb on the surface of SIZnO NHs thereby blocking the active sites of the proteins used for cell wall synthesis. The binding affinity and interaction energies were higher in the case of binding proteins present in gram negative bacteria as compared to that of gram positive bacteria. In addition, a kinetic mathematical model (KMM) was developed in MATLAB to predict the internalization in the bacterial cellular uptake of the ZnO NHs for better understanding of their controlled toxicity. The results obtained from KMM exhibited a good agreement with the experimental data. Exploration of mechanistic interactions, as well as the formation of bioconjugate of proteins and ZnO NHs would play a key role to interpret more complex biological systems in nature. © 2015 American Chemical Society.
Hatamie, A.,
Khan, A.,
Glaby, M.,
Turner, A.P.F.,
Beni, V.,
Mak, W.C.,
Sadollahkhani, A.,
Alnoor, H.,
Zargar, B.,
Bano, S. Langmuir (15205827)31(39)pp. 10913-10921
Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photocatalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photocatalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles. © 2015 American Chemical Society.
Chey, C.O.,
Patra, H.K.,
Tengdelius, M.,
Glaby, M.,
Parlak, O.,
Imani, R.,
Elhag, S.,
Yandi, W.,
Tiwari, A. Advanced Materials Letters (discontinued) (09763961)4(8)pp. 591-597
The length scale for nanomaterial is small enough to be invisible and presume innocence for the initial avoidance of the toxicity issues. Again it was beyond the understanding of the time frame when nanotechnology just blooms that a length scale itself might be an important toxic parameter apart from its materialistic properties. We present this report to address the fundamental issues and questions related to the nanotoxicity issues from laboratory to the land of applications. We emphasize about the basic nanoscale materials that are regularly being used by the scientific community and the nanotechnology basedmaterials that has already in the market or will come soon. © 2013 VBRI press.
