Chitosan-modified glassy carbon

Cai et al. [28] have synthesised AuNPs-labelled ssDNA as a probe to be hybridised with their complementary strand on chitosan-modified glassy carbon electrode (GCE). In their experiments, SH-ssDNA was self-assembled onto an AuNP (16 nm in diameter) (details given previously in Ref. [54]). After hybridisation, the AuNPs tags were detected by differential pulse voltammetry (DPV). The detection limit was 1.0 x 10-9 mol L 1 of 32-base synthesised complementary oligonucleotide. 

Horseradish peroxidase SWCNT/chitosan modified glassy carbon electrode (GCE) Bioelectrochemical sensor [106]... 

Xin, Y., Guanghan, L., Xiaogang, W., Tong, Z. Studies on Electrochemical Behavior of Bromideat a Chitosan-Modified Glassy Carbon Electrode. Electroanalysis. 13, 923-926 (2001)... 

C. Zhao, L. Wan, Q. Wang, S. Liu, and K. Jiao, Highly sensitive and selective uric acid biosensor based on direct electron transfer of hemoglobin-encapsulated chitosan-modified glassy carbon electrode. Anal. Sci., 25 (8), 1013-1017,2009. 

Fig. 6.21 Linear sweep voltammograms recorded at modified glassy carbon electrodes in 5.0 pM NO2, 0.1 M phosphate buffer solution 0.1 Vs potential scan rate. Different electrode coatings have been considered a) carbon nanotubes (CNTs), b) CNTs-Chit, (c) OMIMPF6-CNT-Chit d) (OMIMPFg-CNT) gel, e) (OMIMPFg-CNT) gel-Chit (Chit chitosan OMIMPFe l-octyl-3-methylimidazolium hexafluorophosphate) (Adapted with permission of the authors. Reproduced from Ref. [221] with the permission of Wiley)...

Antolin-Ceron VH, G6mez-Salazar S, Soto V, Avalos-Boija M, Nuno-Donlucas SM (2008) Polymer nanocomposites containing carbon nanotubes and miscible polymer blends based on poly[ethylene-co-(acrylic acid)]. J Appl Polym Sci 108(3) 1462-1472 Babaei A, Babazadeh M (2011) Multi-walled carbon nanotubes/chitosan polymer composite modified glassy carbon electrode for sensitive simultaneous determination of levodopa and morphine. Anal Methods 3(10) 2400-2405... 

Chairam, S., Buddhalee, R, Amatatongchai, M. A novel hydrogen peroxide biosensor based on horseradish peroxidase immobilized on poly(aniline-co-o-aminobenzoic acid) modified glassy carbon electrode coated with chitosan film. Int. J. Electrochem. Sci. 8(8), 10250-10264 (2013)... 

Ye D, Luo L, Ding Y, Chen Q, Liu X (2011) A novel nitrite sensor based on graphene/polyp5UTole/chitosan nanocomposite modified glassy carbon electrode. Analyst 136 4563... 

Chitosan has been utilized along with hydrothermally prepared nano-ZnO nanoparticles for DNA hybridization detection. The detection limit is obtained as 1.09 x 10"11 mol L 1 of complementary target [66], A MWNTs/nanoZnO/CH modified nanocomposite GCE electrode has been used for DNA immobilization via physisorption. This biosensor can effectively discriminate different DNA sequences related to PAT gene in the transgenic com, with detection limit of 2.8 x K)"12 mol/L of target sequence [67], In another report they have deposited ZnO nanoparticles, MWNTs and CH layer onto glassy carbon electrode to immobilize ssDNA probe. A remarkable synergistic effect of the ZnO nanoparticles and MWNTs has been achieved after ssDNA probe immobilization for fabrication of sensitive electrochemical DNA biosensor. The modified electrode shows a wide linear response for DNA hybridization detection. (1.0 x 10"11 to 1.0 x 10"6 mol/L) with detection limit of 2.8 x 1 O 12 mol/L [68],... 

Electrode preparation. A 0.5 % w/w chitosan solution was prepared according to Burchardt et al The PDDA-chitosan film modified electrode was prepared by immobilizing 5 pL of PDDA-chitosan solution [60 pL PDDA (10 % w/w) and 40 uL chitosan (0.5 % w/w)] on the surface of glassy carbon electrode. After drying at room temperature, it was used directly for ECL detection. 

Kang X et al (2007) A novel glucose biosensor based on immobilization of glucose oxidase in chitosan on a glassy carbon electrode modified with gold-platinum alloy nanoparticles/ multiwall carbon nanotubes. Anal Biochem 369(l) 71-79... 

Microelectronic technologies have also been used in nitrite biosensors and electrochemical sensors (Suzuki and Taura, 2001 Adhikari and Majumdar, 2004). Ameida et al. (2013) have also developed a method of electrochemical nitrite measurement by means of a gold working electrode covered with 1,2-diaminobenzene (DAB) integrated in a FIA system. This sensor helps improve selectivity, repeatability, stability, and sensitivity. A Nafion/lead-ruthenate pyrochlore electrode chemically modified for determination of NO2 oxidation and NO reduction based on AC-impedance spectroscopy and FIA has also been tested (Zen et al., 2000). Quan and Shin (2010) also tested an electrochemical nitrite biosensor based on co-immobilization of copper-containing nitrite reductase and viologen-modified chitosan (CHIT-V) on a glassy carbon electrode (GCE). 

Quan, D. and W. Shin. 2010. A nitrite biosensor based on co-immobilization of nitrite reductase and viologen-modified chitosan on a glassy carbon electrode. Sensors (Basel) 10 6241-6256. 

Norouzi et al. used gold nanoparticles and muMwalled carbon nanotubes to promote the electron transfer and catalyze the electro-oxidation of thiocholine in an amperometric biosensor for the detection of monocrotophos (LOD 10 nM). Their flow-based system used glassy carbon electrodes modified with gold nanoparticles and multiwalled carbon nanotubes. The nanotubes contained chitosan to increase the immobilization level and improve the stability of AChE. 

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