A multi-array sensor via the integration of acrylic molecularly imprinted photoresists and ultramicroelectrodes on a glass chip

Abstract

A novel multi-array sensor using molecularly imprinted photoresists (MIPhs) as the recognition element has been fabricated with good resolution, stability and selectivity. The versatility of MIPhs in patterning electrodes with desirable configurations has been demonstrated in our lab previously. Herein, the conventional three-electrode cell was miniaturized within a confined space by taking advantage of photolithography. A novel series of acrylic MIPhs with a resolution of 20 μm were utilized to construct MIPh-based chips (MIPCs), which can discriminate albuterol from the interfering analogies, such as clenbuterol and terbutaline. Excellent selectivity toward these analytes (βAnalytes) was obtained for the MIPCs as compared to the non-template MIPh-based and bare Pt chips. Furthermore, the peak currents of albuterol measured on MIPC have good linear relations with its concentrations in the two ranges of 1-50 μM with the correlation coefficient (R) of 0.9995, and 100-200 μM with R of 0.9999 by differential pulse voltammetry (DPV). As the electrochemical cell on MIPC was reused 20 times, the peak current of albuterol changed from 2.453 pA (pico-ampere) to 1.802 pA with a relative standard deviation (R.S.D.) of 7.88%. The surface morphologies of molecularly imprinted and non-imprinted layers (observed by SEM and AFM) also displayed significantly different features. Because of small size, light weight and high specificity towards the template molecule, the multi-array sensor developed in this work is potentially useful for determining trace electroactive species either in vitro or in vivo. © 2006 Elsevier B.V. All rights reserved.