Effect of receptor attachment on sensitivity of label free microcantilever based biosensor using malachite green aptamer

Abstract

Biosensors are often limited by lesser signal/noise ratio in the detection of low concentration target analyte which may be improved by modifying receptor configuration on the transducer. In this study, we report the improvement in sensitivity, through an increment in surface stress signal, due to the attachment/functionalization of malachite green aptamers with double thiolated ends on microcantilever based sensors, compared to the conventional single thiolated aptamers. Malachite green is deemed to be carcinogenic to humans and its detection using biosensors has been studied by many researchers. Our approach resulted in one order of magnitude improvement in the detection limit for malachite green, on the same sensor. The improvement is attributed to configurational changes of the aptamer on the cantilever surface, induced by the double thiolated attachment, which results in better propagation of mechanical response upon binding with the target malachite green, resulting in higher signal.