Ultrasensitive Quantification of Thyroid-Stimulating Hormone and Thyroxine by Nanoelectronic SnS2 Transistor Sensors

The measurement of thyroid hormones in serum is widely regarded as the most valuable single laboratory tool for assessing thyroid function. This study presents a highly sensitive tin disulfide nanosheet-fabricated field-effect transistor (SnS2-FET) designed for the detections of human thyroid-stimulating hormone (hTSH) and thyroxine (T4). By co-modifying an antibody (AbTSH for detecting hTSH), or a DNA aptamer (AptT4 for detecting T4), with polyethylene glycol (PEG) on the SnS2-FET channel surface, the PEG:AbTSH/SnS2-FET and PEG:AptT4/SnS2-FET devices achieve highly sensitive and selective detections of hTSH and T4, respectively, even in a high ionic strength buffer (1× PBS) or undiluted serum. With a low limit of detection (in the femtomolar level) and a wide linear working range (spanning at least 6 orders of magnitude of analyte concentration), the PEG:AbTSH/SnS2-FET immunosensor and PEG:AptT4/SnS2-FET aptasensor can detect the hTSH and T4 levels encountered in the spectrum of thyroid disorders. Notably, these specific receptor-modified SnS2-FET devices display negligible cross-reactivity with other pituitary hormones or serum components. This research indicates that the nanoelectronic SnS2-FET sensor platforms hold significant potential for point-of-care clinical diagnostics, particularly for the ultrasensitive detection and early screening of medical conditions.