Amperometric biosensor based on carbon nanotubes coated with polyaniline/dendrimer-encapsulated Pt nanoparticles for glucose detection
ABSTRACT A novel amperometric glucose biosensor based on the nanocomposites of multi-wall carbon nanotubes (CNT) coated with polyaniline (PANI) and dendrimer-encapsulated Pt nanoparticles (Pt-DENs) is prepared. CNT coated with protonated PANI is in situ synthesized and Pt-DENs is absorbed on PANI/CNT composite surface by self-assembly method. Then Glucose oxidase (GOx) is crosslink-immobilizated onto Pt-DENs/PANI/CNT composite film. The results show that the fabricated GOx/Pt-DENs/PANI/CNT electrode exhibits excellent response performance to glucose, such as low detection limit (0.5 µM), wide linear range (1 µM–12 mM), short response time (about 5 s), high sensitivity (42.0 µA mM− 1 cm− 2) and stability (83% remains after 3 weeks).
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ABSTRACT: In this paper, single-stranded DNA (ss-DNA) is demonstrated to functionalize graphene (GR) and to further guide the growth of PtAu bimetallic nanoparticles (PtAuNPs) on GR with high densities and dispersion. The obtained nanocomposites (PtAuNPs/ss-DNA/GR) were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectrometer (EDS), and electrochemical techniques. Then, an enzyme nanoassembly was prepared by self-assembling glucose oxidase (GOD) on PtAuNP/ss-DNA/GR nanocomposites (GOD/PtAuNPs/ss-DNA/GR). The nanocomposites provided a suitable microenvironment for GOD to retain its biological activity. The direct and reversible electron transfer process between the active site of GOD and the modified electrode was realized without any extra electron mediator. Thus, the prepared GOD/PtAuNP/ss-DNA/GR electrode was proposed as a biosensor for the quantification of glucose. The effects of pH, applied potential, and temperature on the performance of the biosensor were discussed in detail and were optimized. Under optimal conditions, the biosensor showed a linearity with glucose concentration in the range of 1.0 to 1,800 muM with a detection limit of 0.3 muM (S/N = 3). The results demonstrate that the developed approach provides a promising strategy to improve the sensitivity and enzyme activity of electrochemical biosensors.Nanoscale Research Letters 02/2014; 9(1):99. DOI:10.1186/1556-276X-9-99 · 2.52 Impact Factor
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ABSTRACT: Vertically aligned polyaniline (PANI) structures were prepared by controlling the deposition current density during a stepwise template-free electrochemical deposition process of aniline on a glassy carbon electrode (GCE). Scanning electron micrographs (SEMs) showed the formation of cauliflower PANI structures, each with a diameter of approximately 2-3 and 10 mu m in length. The cauliflower-like PANI electrode was modified with multiwalled carbon nanotubes (cauliflower PANI/MWCNTs) and used as the working electrode for electrochemical detections where H2O2 and glucose were used as the models for the chemical sensor and biosensor, respectively. The sensor provided linearity in the range of 1.0 to 150 mu M of H2O2 with the limit of detection (LOD) of 50 nM. This is 100-fold better than the LOD of the bare GCE. Moreover, this sensor exhibited remarkable operational stability, i.e., 50 mu M H2O2 could be analyzed up to 140 times with a 2.7 % relative standard deviation (RSD). A glucose biosensor was prepared using the modified cauliflower PANI/MWCNT electrode. This had a 3.4 times higher sensitivity than an electrode modified with PANI film/MWCNTs. The regular size and high surface-to-volume ratio of the cauliflower PANI electrode will provide good opportunities for further biosensor applications.Pure and Applied Chemistry 01/2012; 84(10). DOI:10.1351/PAC-CON-11-10-07 · 3.11 Impact Factor
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ABSTRACT: Nitrogen containing carbon layer-coated carbon nanotubes (CNx-CNTs) was prepared as the support for platinum nanoparticles (Pt NPs) and their enhanced properties for electrochemical biosensor has been demonstrated in this paper. The CNx-CNTs were obtained from pyrolysis of polydopamine-wrapped CNTs, which were synthesized by a single deposition process based on the oxidative self-polymerization of dopamine on CNTs. It is found that Pt NPs are deposited on the surface of the CNx-CNTs (Pt/CNx-CNTs) with highly dispersion and small particle size (with an average diameter of 1.7 +/- 0.3 nm). Compared to the nitrogen-free CNTs supported Pt NP composite (Pt/CNTs), the Pt/CNx-CNTs modified glassy carbon (GC) electrode exhibits superior electrocatalytic performance towards the oxidation of hydrogen peroxide (increase by about 55% of response current). Taking glucose oxidase (GOD) as the model, the proposed amperometric enzyme biosensor based on the Pt/CNx-CNTs shows excellent analytical characteristics to glucose detection, such as excellent sustainability in large range of pH values, high sensitivity (66.51 mu A (mmol dm(-3))(-1) cm(-2)), wide linear range (0.01-6.1 mmol dm(-3)) and low detection limit (0.4 mu mol dm(-3)).Electrochimica Acta 10/2014; 143:10–17. DOI:10.1016/j.electacta.2014.07.093 · 4.09 Impact Factor