| Info. | Vol.1 - No.4 (2007.12.20) |
|---|---|
| Title | Development of Electrochemical Biosensing Surfaces Based on the Heat-sensitive Structural Transition of Poly (N-isopropylacrylamide) |
| Authors | Hyoung Gil Choi1, Jun Hwang Lee1,Hyun C. Yoon1 & Dae-Sik Lee2 |
| Institutions | 1Department of Molecular Science & Technology, Ajou University, Suwon 443-749, Korea 2Biosensor Group, ETRI, P.O. Box 106, Yuseong-Gu, Daejeon, 305-350, Korea Correspondence and requests for materials should be addressed to H.C. Yoon (hcyoon@ajou.ac.kr) & D.-S. Lee (dslee@etri.re.kr) |
| Abstract | In this study, we describe a controllable biointerface with an external stimulus based on an intelligent polymer-modified electrode. In order to confer heatsensitivity to the surface, the interface for the immobilization of glucose oxidase (GOX) as a model enzyme was modified using poly (N-isopropylacrylamide) (PNIPAAm), which evidences a rapidly reversible hydrophilic/hydrophobic transition of its conformation in response to changes in temperature. As an underlying surface for modification with PNIPAAm and protein adsorption, and for electrochemical sensing, a dendr-imer monolayer was selfassembled onto a gold substrate and utilized. For the facile attachment of PNIPAAm to the monolayer, N-hydroxysuccinimide-esterified PNIPAAm (NHSPNIPAAm) was synthesized. Following modification, GOX was selectively immobilized on the basis of the structural transition of PNIPAAm via the alteration of the environmental temperature across its lower critical solution tempe-rature (LCST). GOX immobilization levels were determined from the bioelectro-catalytic signals via cyclic voltammetry. The dependence of the GOX immobilization levels on the structural transition of PNIPAAm was also assessed. Following optimi-zation, a difference in GOX surface coverage of approximately 4.96횞10-13 mol쨌cm-2 was achieved between the two operational modes, via merely via alterations in the working temperature. Furthermore, we applied this strategy directly to selective anti-body binding and electrochemical immunosensing on the basis of a biocatalyzed precipitation reaction. |
| Keyword | Electrochemical, PNIPAAm, Heat-responsive, Biosensor |
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