Label‐Free FET Based Biosensor for Detection of Engineered CAR T‐Cells at Single Cell Resolution

Immunotherapy has revolutionized cancer treatment, with Chimeric Antigen Receptor (CAR) T‐cell therapy emerging as a highly effective approach for, e.g., hematological malignancies. However, the complexity of this living drug necessitates efficient methods to ensure the identity of the engineered cells during manufacturing and post‐infusion therapy monitoring. In this study, a proof‐of‐concept is presented using a silicon nanowire field‐effect transistor (SiNW FET) nanosensing platform capable of label‐free, real‐time identification and quantification of CAR T‐cells at single‐cell resolution. The nanosensor's functionalized surface mimics tumor antigens, enabling selective interaction with CAR‐expressing cells. This platform demonstrates exceptional specificity by distinguishing CAR T‐cells from wild‐type T‐cells and quantifying cell populations with ultrasensitivity. These results establish the SiNW FET nanosensing platform as a promising tool for streamlining CAR T‐cell manufacturing and post‐treatment monitoring, improving quality assurance, and advancing clinical applications in immunotherapy.