Journal of Biomedical & Pharmaceutical Engineering

Original Article

Application of Self-Assembled Monolayer of 10-Carboxy-1-Decanethiol for Cholesterol Biosensor

P.R. Solanki¹, S.K. Arya¹, Y. Nishimura², M. Iwamoto², B.D. Malhotra¹

¹ Biomolecular Electronics & Conducting Polymer Research Group, National Physical Laboratory,Dr.K.S.Krishnan Marg, New Delhi-110012, India

² Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1-S3-33, O-okayama, Meguro-ku, Tokyo 152-8552, Japan

Corresponding Author: Pratima R. Solanki

Tel: +91-011-25734273

Fax: +91-011-25726938

Email: pratimasolanki@yahoo.com

ABSTRACT

Cholesterol oxidase (ChOx) has been immobilized on to 10-carboxy-1-decanethiol (CDT) self-assembled monolayer (SAM) prepared on gold (Au) substrate. These bioelectrodes have been characterized using contact angle (CA) measurements, electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) respectively. These ChOx/CDT/Au bioelectrodes have been utilized for the estimation of cholesterol using surface plasmon resonance (SPR), UV-visible and cyclic voltammetric techniques respectively. The linearity has been obtained as 50 to 500 mg/dl of cholesterol in solution with a sensitivity of 2.194x10-4 Abs (mg/dl)-1 and Km value of 4.64 mg/dl. The stability and reusability of these bioelectrodes have been obtained as 3 months and 10-15 times, respectively.

Keywords: Cholesterol oxidase, cholesterol, biosensor, surface plasmon resonance (SPR), 10-carboxy-1-decanethiol (CDT)

Received 26 February 2007; Accepted 2 July 2007

ISSN 1793-4532

Volume 2, Issue 1, Page 7-13