The Experts below are selected from a list of 870 Experts worldwide ranked by ideXlab platform
Peter A Lieberzeit - One of the best experts on this subject based on the ideXlab platform.
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molecularly imprinted polymers to detect profenofos and carbofuran selectively with qcm sensors
Physics in Medicine, 2019Co-Authors: Wongduan Sroysee, Suticha Chunta, Maliwan Amatatongchai, Peter A LieberzeitAbstract:Abstract Two different molecularly imprinted polymers (MIP) were designed to selectively bind the insecticides carbofuran (CBF) and profenofos (PFF). CBF-MIP are based on methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a crosslinker, and azobisisobutyronitrile (AIBN) as an initiator. The PFF-MIP comprised of polyurethane based on poly (4-vinylphenol) (PVP), and diphenyl methane-4,4′-di-isocyanate (DPDI) as functional monomers, phloroglucinol (PG) as the cross-linker, and diphenylmethane (DPM) as the porogen. For sensor measurement, MIPs were spin-coated onto one electrode pair of a dual-electrode QCM, while the second pair was spin-coated with NIPs. Fourier transform infrared (FT-IR) spectroscopy confirms successful template removal from the polymer matrix. The resulting CBF- and PFF-MIP coated onto Quartz Crystal Microbalances (QCMs) lead to pesticide QCM sensors revealing the following analytical characteristics, respectively: dynamic detection range of 0.5–1000 μM for CBF-MIP and 10–1000 μM for PFF-MIP. In both cases, the MIP exhibit roughly ten times higher sensor signals, than the corresponding non-imprinted polymers (NIP).
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low density lipoprotein sensor based on molecularly imprinted polymer
Analytical Chemistry, 2016Co-Authors: Suticha Chunta, Roongnapa Suedee, Peter A LieberzeitAbstract:Increased level of low-density lipoprotein (LDL) strongly correlates with incidence of coronary heart disease. We synthesized novel molecularly imprinted polymers (MIP) as biomimetic specific receptors to establish rapid analysis of LDL levels. For that purpose the ratios of monomers acrylic acid (AA), methacrylic acid (MAA), and N-vinylpyrrolidone (VP), respectively, were screened on 10 MHz dual-electrode Quartz Crystal Microbalances (QCM). Mixing MAA and VP in the ratio 3:2 (m/m) revealed linear sensor characteristic to LDL cholesterol (LDL-C) from 4 to 400 mg/dL or 0.10–10.34 mmol/L in 100 mM phosphate-buffered saline (PBS) without significant interference: high-density lipoprotein (HDL) yields 4–6% of the LDL signal, very-low-density-lipoprotein (VLDL) yields 1–3%, and human serum albumin (HSA) yields 0–2%. The LDL-MIP sensor reveals analytical accuracy of 95–96% at the 95% confidence interval with precision at 6–15%, respectively. Human serum diluted 1:2 with PBS buffer was analyzed by LDL-MIP sensor...
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blood coagulation thromboplastine time measurements on a nanoparticle coated Quartz Crystal microbalance biosensor in excellent agreement with standard clinical methods
Journal of Biosensors and Bioelectronics, 2013Co-Authors: Munawar Hussain, Stefan Sinn, Martin Zeilinger, Hinnak Northoff, Peter A Lieberzeit, Frank K GehringAbstract:Measurements of parameters of hemostasis like thromboplastine time (PT) have primary significance in many clinical settings including extensive surgery, dialysis or innate disorders of hemostasis. Recently, several reports have documented the principle suitability of Quartz Crystal Microbalances (QCM) for measuring parameters of hemostasis like PT or platelet aggregation. But for the establishment of an exact QCM based method as alternative to standard coagulometer measuring QCM coatings with significantly enhanced robustness and reusability have to be worked out. For this purpose we utilized a new semi-automated equipment qCell T for measuring and compared different coatings consisting of polymer films and absorbed nanoparticles (NPs). We demonstrated that affinity based poly ethylene NPs absorbed to polymer films on the QCM constitute a powerful tool with no need for pretreatment for measuring PT in whole blood samples in real time, while these coatings are reusable up to 10 times. PT measurements in excellent agreement with coagulometer tests pave the way for possible future application of QCM in clinical routine.
Debbie Dillon - One of the best experts on this subject based on the ideXlab platform.
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a method for assessment of the genotoxicity of mainstream cigarette smoke by use of the bacterial reverse mutation assay and an aerosol based exposure system
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2014Co-Authors: Joanne Kilford, David Thorne, Annette Dalrymple, Clive Meredith, Rebecca Payne, Julie Clements, Debbie DillonAbstract:Abstract To date there are no widely accepted methods for the toxicological testing of complex gaseous mixtures and aerosols, such as cigarette smoke, although some modifications to the standard regulatory methods have been developed and used. Historically, routine testing of cigarettes has primarily focused on the particulate fraction of cigarette smoke. However, this fraction may not accurately reflect the full toxicity and mutagenicity of the smoke aerosol as a whole, which contains semi-volatiles and short-lived products of combustion. In this study we have used a modified version of the bacterial reverse-mutation (Ames) assay for the testing of mainstream smoke generated from 3R4F reference cigarettes with a Vitrocell® VC 10 exposure system. This method has been evaluated in four strains of Salmonella typhimurium (TA98, TA100, YG1024 and YG1042) and one strain of Escherichia coli (WP2 uvrA pKM101) in the absence and presence of a metabolic activation system. Following exposure at four concentrations of diluted mainstream cigarette-smoke, concentration-related and reproducible increases in the number of revertants were observed in all four Salmonella strains. E. coli strain WP2 uvrA pKM101 was unresponsive at the four concentrations tested. To quantify the exposure dose and to enable biological response to be plotted as a function of deposited mass, Quartz-Crystal Microbalances were included in situ in the smoke-exposure set-up. This methodology was further assessed by comparing the responses of strain YG1042 to mainstream cigarette-smoke on a second VC 10 Smoking Robot. In summary, the Ames assay can be successfully modified to assess the toxicological impact of mainstream cigarette-smoke.
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assessment of cigarette smoke particle deposition within the vitrocell exposure module using Quartz Crystal Microbalances
Chemistry Central Journal, 2013Co-Authors: Jason Adamson, David Thorne, Annette Dalrymple, Debbie Dillon, Clive MeredithAbstract:Cigarette smoking is a cause of a variety of serious diseases, and to understand the toxicological impact of tobacco smoke in vitro, whole smoke exposure systems can be used. One of the main challenges of the different whole smoke exposure systems that are commercially available is that they dilute and deliver smoke in different ways, limiting/restricting the cross-comparison of biological responses. This is where dosimetry – dose quantification – can play a key role in data comparison. Quartz Crystal microbalance (QCM) technology has been put forward as one such tool to quantify smoke particle deposition in vitro, in real-time. Using four identical QCMs, installed into the Vitrocell® mammalian 6/4 CF Stainless exposure module, we were able to quantify deposited smoke particle deposition, generated and diluted by a Vitrocell® VC 10 Smoking Robot. At diluting airflows 0.5-4.0 L/min and vacuum flow rate 5 ml/min/well through the exposure module, mean particle deposition was in the range 8.65 ± 1.51 μg/cm2-0.72 ± 0.13 μg/cm2. Additionally, the effect of varying vacuum flow rate on particle deposition was assessed from 5 ml/min/well - 100 ml/min/well. Mean deposited mass for all four airflows tested per vacuum decreased as vacuum rate was increased: mean deposition was 3.79, 2.75, 1.56 and 1.09 μg/cm2 at vacuum rates of 5, 10, 50 and 100 ml/min/well respectively. QCMs within the Vitrocell® exposure module have demonstrated applicability at defining particle dose ranges at various experimental conditions. This tool will prove useful for users of the Vitrocell® system for dose–response determination and QC purposes.
Clive Meredith - One of the best experts on this subject based on the ideXlab platform.
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a method for assessment of the genotoxicity of mainstream cigarette smoke by use of the bacterial reverse mutation assay and an aerosol based exposure system
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2014Co-Authors: Joanne Kilford, David Thorne, Annette Dalrymple, Clive Meredith, Rebecca Payne, Julie Clements, Debbie DillonAbstract:Abstract To date there are no widely accepted methods for the toxicological testing of complex gaseous mixtures and aerosols, such as cigarette smoke, although some modifications to the standard regulatory methods have been developed and used. Historically, routine testing of cigarettes has primarily focused on the particulate fraction of cigarette smoke. However, this fraction may not accurately reflect the full toxicity and mutagenicity of the smoke aerosol as a whole, which contains semi-volatiles and short-lived products of combustion. In this study we have used a modified version of the bacterial reverse-mutation (Ames) assay for the testing of mainstream smoke generated from 3R4F reference cigarettes with a Vitrocell® VC 10 exposure system. This method has been evaluated in four strains of Salmonella typhimurium (TA98, TA100, YG1024 and YG1042) and one strain of Escherichia coli (WP2 uvrA pKM101) in the absence and presence of a metabolic activation system. Following exposure at four concentrations of diluted mainstream cigarette-smoke, concentration-related and reproducible increases in the number of revertants were observed in all four Salmonella strains. E. coli strain WP2 uvrA pKM101 was unresponsive at the four concentrations tested. To quantify the exposure dose and to enable biological response to be plotted as a function of deposited mass, Quartz-Crystal Microbalances were included in situ in the smoke-exposure set-up. This methodology was further assessed by comparing the responses of strain YG1042 to mainstream cigarette-smoke on a second VC 10 Smoking Robot. In summary, the Ames assay can be successfully modified to assess the toxicological impact of mainstream cigarette-smoke.
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assessment of cigarette smoke particle deposition within the vitrocell exposure module using Quartz Crystal Microbalances
Chemistry Central Journal, 2013Co-Authors: Jason Adamson, David Thorne, Annette Dalrymple, Debbie Dillon, Clive MeredithAbstract:Cigarette smoking is a cause of a variety of serious diseases, and to understand the toxicological impact of tobacco smoke in vitro, whole smoke exposure systems can be used. One of the main challenges of the different whole smoke exposure systems that are commercially available is that they dilute and deliver smoke in different ways, limiting/restricting the cross-comparison of biological responses. This is where dosimetry – dose quantification – can play a key role in data comparison. Quartz Crystal microbalance (QCM) technology has been put forward as one such tool to quantify smoke particle deposition in vitro, in real-time. Using four identical QCMs, installed into the Vitrocell® mammalian 6/4 CF Stainless exposure module, we were able to quantify deposited smoke particle deposition, generated and diluted by a Vitrocell® VC 10 Smoking Robot. At diluting airflows 0.5-4.0 L/min and vacuum flow rate 5 ml/min/well through the exposure module, mean particle deposition was in the range 8.65 ± 1.51 μg/cm2-0.72 ± 0.13 μg/cm2. Additionally, the effect of varying vacuum flow rate on particle deposition was assessed from 5 ml/min/well - 100 ml/min/well. Mean deposited mass for all four airflows tested per vacuum decreased as vacuum rate was increased: mean deposition was 3.79, 2.75, 1.56 and 1.09 μg/cm2 at vacuum rates of 5, 10, 50 and 100 ml/min/well respectively. QCMs within the Vitrocell® exposure module have demonstrated applicability at defining particle dose ranges at various experimental conditions. This tool will prove useful for users of the Vitrocell® system for dose–response determination and QC purposes.
Franz L. Dickert - One of the best experts on this subject based on the ideXlab platform.
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Natural and biomimetic materials for the detection of insulin.
Analytical Chemistry, 2012Co-Authors: Romana Schirhagl, Usman Latif, Dagmar Podlipna, Hans Blumenstock, Franz L. DickertAbstract:Microgravimetric sensors have been developed for detection of insulin by using Quartz Crystal Microbalances as transducers, in combination with sensitive layers. Natural antibodies as coatings were compared with biomimetic materials to fabricate mass-sensitive sensors. For this purpose polyurethane was surface imprinted by insulin, which acts as a synthetic receptor for reversible analyte inclusion. The sensor responses for insulin give a pronounced concentration dependence, with a detection limit down to 1 μg/mL and below. Selectivity studies reveal that these structured polymers lead to differentiation between insulin and glargine. Moreover, antibody replicae were generated by a double imprinting process. Thus, biological recognition capabilities of immunoglobulins are transferred to synthetic polymers. In the first step, natural-immunoglobulin-imprinted nanoparticles were synthesized. Subsequently, these templated particles were utilized for creating positive images of natural antibodies on polymer lay...
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bioimprinted qcm sensors for virus detection screening of plant sap
Analytical and Bioanalytical Chemistry, 2004Co-Authors: Franz L. Dickert, Oliver Hayden, Roland Bindeus, Karl-j. Mann, Dieter Blaas, Elisabeth WaigmannAbstract:Surface imprinting techniques on polymer-coated Quartz-Crystal Microbalances (QCM) have been used to detect tobacco mosaic viruses (TMV) in aqueous media. Molecularly imprinted polymers (MIP), tailor-made by self organisation of monomers around a template (TMV), were generated directly on the gold electrodes. Imprinted trenches on the polymer surface mimicking the shape and surface functionality of the virus serve as recognition sites for re-adsorption after washing out of the template. The sensors are applicable to TMV detection ranging from 100 ng mL−1 to 1 mg mL−1 within minutes. Furthermore, direct measurements without time-consuming sample preparation are possible in complex matrices such as tobacco plant sap.
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Bioimprinting of polymers and sol-gel phases. Selective detection of yeasts with imprinted polymers
Analytical Chemistry, 2002Co-Authors: Franz L. Dickert, Oliver HaydenAbstract:Coated Quartz Crystal Microbalances were modified with a surface-imprinting process using whole yeast cells. These molded polymer and sol-gel surfaces show honeycomb-like structures as shown by atomic force microscopy. Reinclusion of cells allows a selective on-line monitoring of these microorganism concentrations in water over 5 orders of magnitude. The sensitivity to cells holds up in growth media up to 21 g/L. Even cell fragments can be detected in flowing conditions. The highly robust polymers on the sensor devices are suitable for biotechnological applications.
Mark E Cooper - One of the best experts on this subject based on the ideXlab platform.
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a survey of the 2010 Quartz Crystal microbalance literature
Journal of Molecular Recognition, 2012Co-Authors: Robert Speight, Mark E CooperAbstract:In 2010 there has again been an increase in the number of papers published involving piezoelectric acoustic sensors, or Quartz Crystal Microbalances (QCM), when compared to the last period reviewed 2006-2009. The average number of QCM publications per annum was 124 in the period 2001-2005, 223 in the period 2006-9, and 273 in 2010. There are trends towards increasing use of QCM in the study of protein adsorption to surfaces (93% increase), homeostasis (67% increase), protein-protein interactions (40% increase), and carbohydrates (43% increase). New commercial systems have been released that are driving the uptake of the technology for characterisation of binding specificities, affinities, kinetics and conformational changes associated with a molecular recognition event. This article highlights theoretical and practical aspects of the principals that underpin acoustic analysis, then reviews exemplary papers in key application areas involving small molecular weight ligands, carbohydrates, proteins, nucleic acids, viruses, bacteria, cells, and membrane interfaces.
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a survey of the 2001 to 2005 Quartz Crystal microbalance biosensor literature applications of acoustic physics to the analysis of biomolecular interactions
Journal of Molecular Recognition, 2007Co-Authors: Mark E Cooper, Victoria T SingletonAbstract:The widespread exploitation of biosensors in the analysis of molecular recognition has its origins in the mid-1990s following the release of commercial systems based on surface plasmon resonance (SPR). More recently, platforms based on piezoelectric acoustic sensors (principally 'bulk acoustic wave' (BAW), 'thickness shear mode' (TSM) sensors or 'Quartz Crystal Microbalances' (QCM)), have been released that are driving the publication of a large number of papers analysing binding specificities, affinities, kinetics and conformational changes associated with a molecular recognition event. This article highlights salient theoretical and practical aspects of the technologies that underpin acoustic analysis, then reviews exemplary papers in key application areas involving small molecular weight ligands, carbohydrates, proteins, nucleic acids, viruses, bacteria, cells and lipidic and polymeric interfaces. Key differentiators between optical and acoustic sensing modalities are also reviewed.