Raman spectroscopy detects cardiac allograft rejection with molecular specificity.

Spatially resolved Raman spectroscopy is shown here to be capable of molecular-specific detection without exogenous labeling. This molecular specificity is achieved by detecting the strong and characteristic Raman spectral signature of an indole derivative, serotonin, whose selective existence in rejected heart transplants serves as the biomarker. The study also corroborates the increasingly recognized role of serotonin receptors in various immune responses, including cardiac allograft rejection. Combining both medical and physical sciences, this work demonstrates the potential use of Raman spectroscopy in replacing the invasive endomyocardial biopsy as the standard for post-transplantation rejection surveillance and presents a new paradigm in advancing clinical care through interdisciplinary studies.