title: Highly sensitive electrocatalytic biosensing of hypoxanthine based on functionalization of graphene sheets with water-soluble conducting graft copolymer.
abstract: A novel electrocatalytic biosensing platform was designed by the functionalization of reduced graphene oxide sheets (RGO) with conducting polypyrrole graft copolymer, poly(styrenesulfonic acid-g-pyrrole) (PSSA-g-PPY), via π-π noncovalent interaction. The resulting nanocomposite could well disperse in water for at least 2 months with a solubility of 3.0 mg mL(-1). The nanocomposite was characterized with atomic force microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible absorption, contact angle measurement, and electrochemical impedance spectroscopy. Based on the advantageous functions of PSSA-g-PPY and RGO, the functional nanocomposite modified platinum electrode showed high electrocatalytic activity toward the oxidation of hydrogen peroxide and uric acid in neutral media. Further, a hypoxanthine biosensor was constructed by combining the modified electrode with the enzymatic reaction of xanthine oxidase. The biosensor exhibited a wide linear response ranging from 3.0×10(-8) to 2.8×10(-5) M with a high sensitivity of 673±4 μA M(-1) cm(-2). The detection limit of 10nM at a signal-to-noise ratio of 3 was one order of magnitude lower than that reported previously. The assay results of hypoxanthine in fish samples were in a good agreement with the reference values. The water-soluble conducting copolymer could serve as an efficient species for functionalization and solubilization of graphene sheets in biosensing and biocatalytic applications.
authors: Key Laboratory of Analytical Chemistry for Life Science (Ministry of Education of China), Department of Chemistry, Nanjing University, Nanjing 210093, PR China.
authors: Jing
authors: J
authors: Zhang
authors: Jianping
authors: J
authors: Lei
authors: Rong
authors: R
authors: Pan
authors: Yadong
authors: Y
authors: Xue
authors: Huangxian
authors: H
authors: Ju
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002384:Catalysis; D003217:Conductometry / Q000295:instrumentation*; D004553:Electric Conductivity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D019271:Hypoxanthine / Q000032:analysis* / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D011108:Polymers; D011137:Polystyrenes; D011758:Pyrroles; D014867:Water; D019271:Hypoxanthine; C067635:polypyrrole; C003321:polystyrene sulfonic acid; D006108:Graphite