Bisphenol A detection using molybdenum disulfide (MoS₂) field-effect transistor functionalized with DNA aptamers

Bisphenol A exposure, even at very low concentrations, is associated with an increased risk of high blood pressure, heart disease, diabetes and some cancers. It is important to monitor BPA exposure level for human healthcare. Two-dimensional materials-based field-effect transistors are promising for sensing applications due to their high sensitivity, label-free detection, and reusability. Among 2D materials MoS₂ based semiconductor materials provides higher sensitivity compared to the lack of sensitive existing graphene materials due to bandgap. In this work, a microfluidic device based on MoS₂ field-effect transistor is demonstrated that can be adapted to detect several biomolecules at very low concentrations. MoS₂ channel is functionalized by depositing gold nanoparticles and immobilizing single one (or double)-stranded DNA. It is found that dsDNA functionalized devices exhibit higher sensitivity compared to ssDNA for all BPA concentrations due to p-doing effect of dsDNA on MoS₂ semiconducting surface. Both ss and dsDNA functionalized MoS₂ FET devices are able to detect BPA concentration as low as 1 pg mL⁻¹, as observed by a 4.27% and 2.17% change in the current, respectively, and a response time of about ≈4 s. The demonstrated MoS₂ FET sensors are very promising to detect lower concentration biomolecules and DNA in biomedical applications.