Engineering Ta-doped MoSe_x sensitive films in extended-gate field-effect transistors for ultrahigh sensitivity detection of epinephrine at fM levels

This study presents the production of Ta-doped MoSe_x films on a flexible polyimide (PI)-based extended-gate field-effect transistor (EGFET) using a straightforward sputtering technique, which is applied for the first time in the evaluation of epinephrine. The Ta-doped MoSe_x-based EGFET flexible PI sensor through the functionalization of 4-formylphenylboronic acid (4-FPBA), a synthetic receptor allowing for the covalent attachment of epinephrine on the sensing surface. The sensitivity to epinephrine reached 11.48 mV/C_EP, with a linearity of 99.912 % within the concentration range of 10^-8 to 0.01 μM. Additionally, this flexible sensor exhibited a heightened reference voltage shift response to epinephrine when compared to other neurotransmitters. The successful implementation of this straightforward sputtering engineering method, capable of effectively modifying both the surface and composition of the Ta-doped MoSe_x film, paves the way for exploring new possibilities in developing diverse types of flexible and adjustable biosensors.