Glucose biosensor from covalent immobilization of chitosan-coupled carbon nanotubes on polyaniline-modified gold electrode.
An amperometric glucose biosensor was prepared using polyaniline (PANI) and chitosan-coupled carbon nanotubes (CS-CNTs) as the signal amplifiers and glucose oxidase (GOD) as the glucose detector on a gold electrode (the Au-g-PANI-c-(CS-CNTs)-GOD biosensor). The PANI layer was prepared via oxidative graft polymerization of aniline from the gold electrode surface premodified by self-assembled monolayer of 4-aminothiophenol. CS-CNTs were covalently coupled to the PANI-modified gold substrate using glutaradehyde as a bifunctional linker. GOD was then covalently bonded to the pendant hydroxyl groups of chitosan using 1,4-carbonyldiimidazole as the bifunctional linker. The surface functionalization processes were ascertained by X-ray photoelectron spectroscopy (XPS) analyses. The field emission scanning electron microscopy (FESEM) images of the Au-g-PANI-c-(CS-CNTs) electrode revealed the formation of a three-dimensional surface network structure. The electrode could thus provide a more spatially biocompatible microenvironment to enhance the amount and biocatalytic activity of the immobilized enzyme and to better mediate the electron transfer. The resulting Au-g-PANI-c-(CS-CNTs)-GOD biosensor exhibited a linear response to glucose in the concentration range of 1-20 mM, good sensitivity (21 μA/(mM·cm(2))), good reproducibility, and retention of >80% of the initial response current after 2 months of storage.
Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore.
Dong
D
Wan
Shaojun
S
Yuan
G L
GL
Li
K G
KG
Neoh
E T
ET
Kang
D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques; D002240:Carbohydrate Sequence; D048271:Chitosan / Q000737:chemistry*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005947:Glucose / Q000138:chemical synthesis / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D008969:Molecular Sequence Data; D037742:Nanotubes, Carbon / Q000737:chemistry*; D013499:Surface Properties
D000814:Aniline Compounds; D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D006046:Gold; D048271:Chitosan; D005947:Glucose