Carbon nanotube field effect transistor aptasensors for estrogen detection in liquids

Abstract

The authors demonstrate a small molecule 17 β-estradiol (E2) sensor based on aptamer functionalized carbon nanotube network film field effect transistors (CNT FETs). The real time current response for the 35-mer E2 aptamer functionalized CNT FET shows a clear increase in current over the range of 50 nM to 1.6 μM of E2. The E2 response using a longer 75-mer version of the aptamer functionalized CNT FETs, where the aptamer/E2 binding occurs beyond the Debye length, shows no obvious evidence of sensing. The CNT FET sensing platform has been fabricated via a simple surfactant free solution processing route, compatible with further carbon nanotube functionalization to develop a versatile sensing platform. The CNT FET aptasensors are able to perform real time monitoring of E2 levels for selective and quantitative detection of E2 in liquids.