Specific and Label‐Free Sensing of Prostate‐Specific Antigen (PSA) from an Ultrasmall Drop of Diluted Human Serum with the Meta‐Nano‐Channel Silicon Field‐Effect Biosensor

AbstractSelf‐use tests are the future of medical diagnostics. Hence, there is a need for low‐cost, simple‐to‐use sensing of multiple analytes from ultrasmall physiological samples. The Meta‐Nano‐Channel (MNC) field‐effect biosensor is employed for sensing of prostate‐specific antigen (PSA). The novelty of the MNC biosensor is: (1) it allows to optimize the coupling between the electrostatics of the biological interactions and the readout current, and (2) it allows to electrostatically affect the biological complexes postinteraction. These attributes yield an optimized and tunable sensing performance. The MNC biosensor is fabricated in a high‐volume silicon chip factory for this research, and an excellent repeatability and robustness in an environment of 1:100 diluted serum is demonstrated. Specific and label‐free PSA sensing is demonstrated from ultrasmall 0.5 µL drops of 1:100 diluted serum with a limit‐of‐detection of 1 fg mL−1, and excellent linearity over a concentration range of six orders of magnitude. Importantly, the attributes of the MNC biosensor allow for a tunable sensitivity and a tunable dynamic range.