Advances in biosensors for monitoring immune responses and allograft rejection in organ transplantation.

Organ transplantation remains a gold-standard intervention for numerous end-stage organ failure diseases. However, allograft rejection is still a barrier to long-term graft survival. Conventional allograft monitoring approaches, including tissue biopsies and functional evaluations, are constrained by their invasiveness, limited specificity, and time-consuming nature. Biosensor platforms have emerged as promising tools for rapid, sensitive, and non-invasive detection in a wide range of clinical diagnoses, including the evaluation of immune activity and allograft rejection. This review highlights recent advances in biosensor platforms for post-transplant surveillance. While these technologies are associated with promising outcomes in terms of sensitivity and specificity in preclinical and pilot studies, their translational application requires reliable validation and standardization along with proper safety assessments. Biosensor platforms and point-of-care systems, especially when combined with artificial intelligence (AI), can dramatically improve post-transplant care, enabling timely therapeutic interventions and enhancing graft survival. Many of the discussed examples remain at a pre-clinical stage in rodent models and, while promising as proof-of-concept, require substantial further validation before clinical application.