Improved enzyme immobilization for enhanced bioelectrocatalytic activity of choline sensor and acetylcholine sensor

• Published in: Sensors and actuators. B, Chemical Chemical, 2014-03, Vol.193, p.904-910
• Main Authors: Zhang, Leitao, Chen, Jing, Wang, Yiting, Yu, Lei, Wang, Jing, Peng, Hui, Zhu, Jianzhong
• Format: Article
• Language: English
• Subjects: Acetylcholine biosensor; Actuators; Biochemistry; Choline; Choline biosensor; Multi wall carbon nanotubes; Multilayers; Nanoparticles; Oxidase; Sensors; Synergic action; ZnO nanoparticles
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2013.11.092

•The biosensor for choline and acetylcholine is composed of MWCNTs and ZnO NPs followed by a bienzyme layer and a capping layer of PDDA.•The uniqueness of this sensor is the incorporation of ZnO nanoparticles.•The biosensor exhibits a quality characterization, such as high sensitivity, long term stability, a relatively wide linear range and a limit of detection of 0.3μM. In this work, we report the development of a highly sensitive and stable choline/acetylcholine sensor based on the synergetic effect of multi-walled carbon nanotubes and ZnO nanoparticles. This unique multi-layer structure provided a favorable microenvironment to maintain the bioactivity of choline oxidase and acetylcholinesterase, which led to a rapid amperometric response to choline and acetylcholine. This nanomaterials-based choline/acetylcholine sensor was highly sensitive and showed good stability over a relatively long-term storage (90 days). The sensor prepared by loading 1.0-unit choline oxidase and acetylcholinesterase showed a linear response range of 1.0μM to 0.8mM and 1.0μM to 1.0mM, a sensitivity of 178μAmM−1cm−2 and 180μAmM−1cm−2, and a detection limit of 0.3μM, respectively. The sensor prepared was used to detect choline in human blood plasma samples, and the obtained results were consistent with those of the HPLC–MS/MS assay.