Field-effect transistor bioassay for ultrasensitive detection of folate receptor 1 by ligand-protein interaction.

A miniaturized and integrated bioassay was developed based on molybdenum disulfide (MoS2) field-effect transistor (FET) functionalized with bovine serum albumin-folic acid (BSA-FA) for monitoring FOLR1. We performed the electrical test of FOLR1 within the range 100 fg/mL to 10 ng/mL, and the limit of detection was 0.057 pg/mL. The ultrahigh sensitivity of the bioassay was realized by ligand-protein interaction between FA and FOLR1, with a ligand-protein binding ratio of 3:1. The formation of FA-FOLR1 was confirmed with ELISA. The binding affinity dissociation constant KD was 12 ± 6 pg/mL. This device can work well for FOLR1 detection in human serum, which presents its promising application in point-of-care diagnosis. This study supports the future applications of such ligand-protein-based bioassays in the clinical practices. Graphical abstract MoS2-based FET device for detecting folate receptor 1 (FOLR1) was fabricated. The molecular folic acid as a probe can specifically bound to FOLR1 with a high affinity.