A novel competitive capacitive glucose biosensor based on concanavalin A-labeled nanogold colloids assembled on a polytyramine-modified gold electrode

作者：Labib Mahmoud; Hedstrom Martin; Amin Magdy; Mattiasson Bo^*

来源：Analytica Chimica Acta, 2010, 659(1-2): 194-200.

DOI：10.1016/j.aca.2009.11.028

• Competitive capacitive biosensor
• Concanavalin A
• Glucose
• Nanogold
• Polytyramine

A highly sensitive competitive capacitive glucose biosensor was constructed based on gold nanoparticles. which were employed as a platform to immobilize concanavalin A (Con A). Cold nanoparticles were fixed on a gold electrode, on which a layer of polytyramine was preformed via electrochemical polymerization. The sensing mechanism is based on the competitive dissociation of a glucose polymer or a glycoconjugate from the glycoligand binding sites of immobilized Con A by the added glucose. To further improve the sensor response, several glucose polymers as well as a synthesized glycoconjugate using the periodate method, were screened. Consequently, dextran (MW 39 kDa) was selected and the feasibility of the proposed biosensor was evaluated for a competitive assay of glucose. Experimental results show that the biosensor responded linearly to glucose in the range from 1.0 X 10(-6) to 1.0 X 10(-2) M, corresponding to 0.18 mu g mL(-1) to 1.8 mg mL(-1) of glucose with a detection limit of 1.0 x 10(-6) M under optimized conditions. The studied biosensor exhibited a response time of about 15 min and a neglectable loss in sensitivity after 10 repeated analytical cycles.

• 出版日期2010-2-5