Materials and Interface Designs of Waterproof Field‐Effect Transistor Arrays for Detection of Neurological Biomarkers

The continuous, real-time, and concurrent detection of multiple biomarkers in bodily fluids is of high significance for advanced healthcare. While active, semiconductor-based biochemical sensing platforms provide levels of functionality exceeding those of their conventional passive counterparts, the stability of the active biosensors in the liquid environment for continuous operation remains a challenging topic. This work reports the development of a class of flexible and waterproof field-effect transistor arrays for multiplexed biochemical sensing. In this design, monolithic, ultrathin, dense, and low defect nanomembranes consisting of monocrystalline Si and thermally grown SiO2 simultaneously serve as high-performance backplane electronics for signal transduction and stable biofluid barriers with high structural integrity due to the high formation temperature. Coupling the waterproof transistors with various ion-selective membranes through the gate electrode allows for sensitive and selective detection of multiple ions as biomarkers for traumatic brain injury. The study also demonstrates a similar encapsulation structure which enables the design of waterproof amperometric sensors based on this materials strategy and integration scheme. Overall, key advantages in flexibility, stability, and multifunctionality highlight the potential of using such electronic sensing platforms for concurrent, continuous detection of various neurological biomarkers, proving a promising approach for early diagnosis and intervention of chronic diseases.