Near-Infrared Multilayer MoS2 Photoconductivity-Enabled Ultrasensitive Homogeneous Plasmonic Colorimetric Biosensing

The ability to detect low-abundance proteins in human body fluids plays a critical role in proteomic research to achieve a comprehensive understanding of protein functions and early-stage disease diagnosis to reduce mortality rates. Ultrasensitive (sub-fM), rapid, simple "mix-and-read" plasmonic colorimetric biosensing of large-size (approximate to 180 kDa) proteins in biofluids using an ultralow-noise multilayer molybdenum disulfide (MoS2) photoconducting channel is reported here. With its out-of-plane structure optimized to minimize carrier scattering, the multilayer MoS2 channel operated under near-infrared illumination enables the detection of a subtle plasmonic extinction shift caused by antigen-induced nanoprobe aggregation. The demonstrated biosensing strategy allows quantifying carcinoembryonic antigen in unprocessed whole blood with a dynamic range of 10(6), a sample-to-answer time of 10 min, and a limit of detection of 0.1-3 pg mL(-1), which is approximate to 100-fold more sensitive than the clinical-standard enzyme-linked immunosorbent assays. The biosensing methodology can be broadly used to realize timely personalized diagnostics and physiological monitoring of diseases in point-of-care settings.