title: A novel nitrite biosensor based on the direct electron transfer of hemoglobin immobilized on CdS hollow nanospheres.
abstract: A novel nitrite biosensor based on the direct electron transfer of hemoglobin (Hb) immobilized on CdS hollow nanospheres (HS-CdS) modified glassy carbon electrode was constructed. The direct electron transfer of Hb showed a pair of redox peaks with a formal potential of -286 mV (vs. SCE) in 0.1M pH 7.0 phosphate buffer solution. It was a surface-controlled electrode process involving a single proton transfer coupled with a reversible one-electron transfer for each heme group of Hb. HS-CdS had a large specific surface area and good biocompatibility and had a better electrochemical response than that of solid spherical CdS. The immobilized Hb on HS-CdS displayed an excellent response to NO(2)(-) with one irreversible electrode process for NO reduction. Under optimal conditions, the biosensor could be used for the determination of NO(2)(-) with a linear range from 0.3 to 182 microM and a detection limit of 0.08 microM at 3 sigma based on the irreversible reduction of NO. HS-CdS provided a good matrix for protein immobilization and had a promising application in constructing sensors.
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, PR China. daizhihuii@njnu.edu.cn
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Dai
authors.forename: Hongyan
authors.initials: H
authors.lastname: Bai
authors.forename: Mei
authors.initials: M
authors.lastname: Hong
authors.forename: Yinyan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Jianchun
authors.initials: J
authors.lastname: Bao
authors.forename: Jian
authors.initials: J
authors.lastname: Shen
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation*; D019187:Cadmium Compounds / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006454:Hemoglobins / Q000737:chemistry*; D054118:Nanospheres / Q000737:chemistry* / Q000648:ultrastructure; D009573:Nitrites / Q000032:analysis* / Q000737:chemistry; D016062:Porosity; D011485:Protein Binding; D018036:Selenium Compounds / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D006454:Hemoglobins; D009573:Nitrites; D018036:Selenium Compounds; C058667:cadmium selenide