The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Shenming Chen - One of the best experts on this subject based on the ideXlab platform.
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a simple strategy for the immobilization of catalase on multi walled carbon nanotube poly l lysine biocomposite for the detection of h2o2 and iodate
Biosensors and Bioelectronics, 2014Co-Authors: A Ezhil T Vilian, Shenming Chen, Bihshow LouAbstract:Herein, we report a novel third-generation H2O2 and IO3- biosensor, which was fabricated by loading catalase (CAT) onto l-lysine/multiwalled carbon nanotube (PLL/f-MWCNT) Film Modified glassy carbon electrode (GCE). The UV-visible (UV-vis) and Fourier-transform infrared (FTIR) spectra show that the catalase encapsulated in the PLL/f-MWCNT Film can effectively retain its bioactivity. The immobilized CAT retained its bioactivity with a high protein loading of 4.072 × 10(-10) mol cm(-2), thus exhibiting a surface-controlled reversible redox reaction, with a fast heterogeneous electron transfer rate of 5.48 s(-1). The immobilized CAT shows a couple of reversible and well-defined cyclic voltammetry peaks with a formal potential (E(0)) of -0.471 V (vs. Ag/AgCl) in a pH 6.5 phosphate buffer solution (PBS). Moreover, the Modified Film exhibited high electrocatalytic activity for the reduction of hydrogen peroxide (H2O2). It exhibited a wide linear response to H2O2 in the concentration range of 1 × 10(-6) - 3.6 × 10(-3), with higher sensitivity (392 mA cm(-2) M(-1)) and a lower Michaelis-Menten constant (0.224 mM). It provided high-catalytic activity towards H2O2 in a shorter time (5s), with a detection limit of 8 nM. These results indicate great improvement in the electrochemical and electrocatalytic properties of the CAT/PLL/f-MWCNT biosensor, offering a new idea for the design of third-generation electrochemical biosensors.
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direct electrochemistry of glucose oxidase at electrochemically reduced graphene oxide multiwalled carbon nanotubes hybrid material Modified electrode for glucose biosensor
Biosensors and Bioelectronics, 2013Co-Authors: Veerappan Mani, Balamurugan Devadas, Shenming ChenAbstract:Abstract Direct electrochemistry of glucose oxidase (GOx) at an electrochemically reduced graphene oxide–multiwalled carbon nanotubes hybrid (ERGO–MWCNT) Modified glassy carbon electrode (GCE) has been reported. The π–π stacking interaction operating between the MWCNT and graphene oxide (GO) has been revealed by UV–Vis absorption spectroscopy. GOx was well immobilized onto the ERGO–MWCNT hybrid Film, as a result direct electrochemistry of GOx has been achieved. Compared with pristine MWCNT, 2.1 fold higher peak current and very low peak to peak separation (ΔEp) of 26 mV were observed at the hybrid Film, demonstrating faster electron transfer between GOx and the Modified electrode surface. Moreover, the Modified Film exhibited high electrocatalytic activity towards glucose via reductive detection of oxygen consumption and in the presence of mediator. The proposed biosensor exhibits low detection limit of 4.7 μM with wide linear range of 0.01–6.5 mM and acquires excellent storage and operational stabilities. The accurate glucose determination in human blood serum and good recoveries achieved in spiked urine samples revealed their great potential in the practical applications.
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direct electrochemistry of glucose oxidase at electrochemically reduced graphene oxide multiwalled carbon nanotubes hybrid material Modified electrode for glucose biosensor
Biosensors and Bioelectronics, 2013Co-Authors: Veerappan Mani, Balamurugan Devadas, Shenming ChenAbstract:Abstract Direct electrochemistry of glucose oxidase (GOx) at an electrochemically reduced graphene oxide–multiwalled carbon nanotubes hybrid (ERGO–MWCNT) Modified glassy carbon electrode (GCE) has been reported. The π–π stacking interaction operating between the MWCNT and graphene oxide (GO) has been revealed by UV–Vis absorption spectroscopy. GOx was well immobilized onto the ERGO–MWCNT hybrid Film, as a result direct electrochemistry of GOx has been achieved. Compared with pristine MWCNT, 2.1 fold higher peak current and very low peak to peak separation (ΔEp) of 26 mV were observed at the hybrid Film, demonstrating faster electron transfer between GOx and the Modified electrode surface. Moreover, the Modified Film exhibited high electrocatalytic activity towards glucose via reductive detection of oxygen consumption and in the presence of mediator. The proposed biosensor exhibits low detection limit of 4.7 μM with wide linear range of 0.01–6.5 mM and acquires excellent storage and operational stabilities. The accurate glucose determination in human blood serum and good recoveries achieved in spiked urine samples revealed their great potential in the practical applications.
And S K Hark - One of the best experts on this subject based on the ideXlab platform.
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effects of trifluoroacetic acid modification on the surface microstructures and photocatalytic activity of mesoporous tio2 thin Films
Langmuir, 2003Co-Authors: And S K HarkAbstract:Enhancement of the photocatalytic activity of sol−gel-derived TiO2 thin Films by a simple treatment with trifluoroacetic acid (TFA) was investigated. The thin Films were characterized with N2 adsorption, Fourier transform infrared spectroscopy, UV−visible spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, X-ray diffraction, atomic force microscopy, and differential thermal analysis/thermogravimetry analysis. The photocatalytic activity of the thin Films was evaluated by the photocatalytic decomposition of acetone in air. The results show that TFA is chemisorbed on the surface of the TiO2 Films as a trifluoroacetate complex. The photocatalytic activity of Modified TiO2 thin Films is higher than that of unModified TiO2 thin Films, and the Modified Film treated at 250 °C shows the highest activity. This is ascribed to the fact that the TFA complex bound on the surface of TiO2 acts as an electron scavenger and, thus, reduces the recombination of photogenerated electrons and holes....
Veerappan Mani - One of the best experts on this subject based on the ideXlab platform.
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direct electrochemistry of glucose oxidase at electrochemically reduced graphene oxide multiwalled carbon nanotubes hybrid material Modified electrode for glucose biosensor
Biosensors and Bioelectronics, 2013Co-Authors: Veerappan Mani, Balamurugan Devadas, Shenming ChenAbstract:Abstract Direct electrochemistry of glucose oxidase (GOx) at an electrochemically reduced graphene oxide–multiwalled carbon nanotubes hybrid (ERGO–MWCNT) Modified glassy carbon electrode (GCE) has been reported. The π–π stacking interaction operating between the MWCNT and graphene oxide (GO) has been revealed by UV–Vis absorption spectroscopy. GOx was well immobilized onto the ERGO–MWCNT hybrid Film, as a result direct electrochemistry of GOx has been achieved. Compared with pristine MWCNT, 2.1 fold higher peak current and very low peak to peak separation (ΔEp) of 26 mV were observed at the hybrid Film, demonstrating faster electron transfer between GOx and the Modified electrode surface. Moreover, the Modified Film exhibited high electrocatalytic activity towards glucose via reductive detection of oxygen consumption and in the presence of mediator. The proposed biosensor exhibits low detection limit of 4.7 μM with wide linear range of 0.01–6.5 mM and acquires excellent storage and operational stabilities. The accurate glucose determination in human blood serum and good recoveries achieved in spiked urine samples revealed their great potential in the practical applications.
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direct electrochemistry of glucose oxidase at electrochemically reduced graphene oxide multiwalled carbon nanotubes hybrid material Modified electrode for glucose biosensor
Biosensors and Bioelectronics, 2013Co-Authors: Veerappan Mani, Balamurugan Devadas, Shenming ChenAbstract:Abstract Direct electrochemistry of glucose oxidase (GOx) at an electrochemically reduced graphene oxide–multiwalled carbon nanotubes hybrid (ERGO–MWCNT) Modified glassy carbon electrode (GCE) has been reported. The π–π stacking interaction operating between the MWCNT and graphene oxide (GO) has been revealed by UV–Vis absorption spectroscopy. GOx was well immobilized onto the ERGO–MWCNT hybrid Film, as a result direct electrochemistry of GOx has been achieved. Compared with pristine MWCNT, 2.1 fold higher peak current and very low peak to peak separation (ΔEp) of 26 mV were observed at the hybrid Film, demonstrating faster electron transfer between GOx and the Modified electrode surface. Moreover, the Modified Film exhibited high electrocatalytic activity towards glucose via reductive detection of oxygen consumption and in the presence of mediator. The proposed biosensor exhibits low detection limit of 4.7 μM with wide linear range of 0.01–6.5 mM and acquires excellent storage and operational stabilities. The accurate glucose determination in human blood serum and good recoveries achieved in spiked urine samples revealed their great potential in the practical applications.
Voravee P Hoven - One of the best experts on this subject based on the ideXlab platform.
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surface modification of chitosan Films effects of hydrophobicity on protein adsorption
Carbohydrate Research, 2003Co-Authors: Varawut Tangpasuthadol, Noppong Pongchaisirikul, Voravee P HovenAbstract:The surface of chitosan Films was Modified using acid chloride and acid anhydrides. Chemical composition at the Film surface was analyzed by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). ATR-FTIR data verified that the substitution took place at the amino groups of chitosan, thus forming amide linkages, and the modification proceeded to the depth at least 1 microm. Choices of molecules substituted at the amino groups of the glucosamine units did affect the hydrophobicity of the Film surface, as indicated by air-water contact angle analysis. The surface became more hydrophobic than that of non-Modified Film when a stearoyl group (C(17)H(35)CO-) was attached to the Films. The reaction of chitosan Films with succinic anhydride or phthalic anhydride, however, produced more hydrophilic Films. Selected Modified Films were subjected to protein adsorption study. The amount of protein adsorbed, determined by bicinchoninic acid (BCA) assay, related to the types of attached molecules. The improved surface hydrophobicity affected by the stearoyl groups promoted protein adsorption. In contrast, selective adsorption behavior was observed in the case of the chitosan Films Modified with anhydride derivatives. Lysozyme adsorption was enhanced by H-bonding and charge attraction with the hydrophilic surface. While the amount of albumin adsorbed was decreased possibly due to negative charges that gave rise to repulsion between the Modified surface and albumin. This study has demonstrated that it is conceivable to fine-tune surface properties which influence its response to bio-macromolecules by heterogeneous chemical modification.
How Yong Ng - One of the best experts on this subject based on the ideXlab platform.
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Modified models to predict flux behavior in forward osmosis in consideration of external and internal concentration polarizations
Journal of Membrane Science, 2008Co-Authors: How Yong NgAbstract:Abstract The inherent challenge of the forward osmosis (FO) process is the severity of both external (ECP) and internal concentration polarization (ICP), which significantly reduces the water flux across the highly selective membrane. In this study, the impacts of concentration polarization on flux behavior were investigated. A Modified-Film model developed using the boundary layer concept described the ECP layer much better than previously used models. By including the diffusion coefficient into the derivative of the governing convective-diffusion equations, the predicted water flux due to ICP was in excellent agreement with experimental flux data. This was attributed to the usage of a better solute resistivity constant within the porous support layer, K*, which is independent of the diffusivity coefficient. Laboratory experiments were carried out to account for both ECP and ICP and the associated water fluxes were verified with the improved models. Previous models overestimated the water flux by as much as 15% of the experimental flux and the Modified models showed significant improvements in flux prediction for the FO process, particularly at higher draw solution concentration. A better understanding of the effects of concentration polarization achieved from this study could allow us to further modify the FO membrane structure to improve water flux.