Ultrasensitive WSe₂field-effect transistor-based biosensor for label-free detection of cancer in point-of-care applications

We demonstrate a highly sensitive tungsten diselenide (WSe2) field-effect transistor (FET) biosensor for label-free detection of early stage prostate cancer. We modified the FET channel by attaching the monoclonal antibody of prostate specific antigen (anti-PSA) through a multi-step process, followed by bovine serum albumin treatment, which ensures specific binding between anti-PSA and PSA. Our FET biosensor has a detection limit of 10 fg ml-1 PSA, the lowest concentration detected so far by any FET sensor. At this detection limit, the sub-threshold swing is 235 mV dec-1; and the drain current (Id) in the FET increases by 70% compared to that in a pristine device. The FET sensor exhibits linear change in threshold voltage (Vth) and drain current (Id) over the detection range of 10 fg ml-1-1 ng ml-1 PSA. Our demonstrated ultra-sensitive and fast WSe2 FET biosensors are promising for point-of-care diagnostics applications.