A chemical probe for prostate-specific membrane antigen for real-time Raman imaging of prostate cancer cells

Intraoperative detection of localised prostate cancer is challenging with direct consequences for long-term, suc-cessful treatment of the disease. Optical imaging techniques have been incorporated in the surgical environment, often using theranostic agents to rapidly and accurately determine the tumour margin. Here, we develop the first small molecule probe that specifically targets prostate-specific membrane antigen (PSMA) for detection using stimulated Raman scattering (SRS) microscopy. The incorporation of an alkyne tag into the glutamate-ureido-lysine moiety, which has high affinity for PSMA, yielded the probe, PSMA-BADY. The selectivity and specificity of the probe was established in prostate cancer cell models with known PSMA expression profiles, indicating the potential of PSMA-BADY for localising PSMA in multicellular environ-ments using SRS microscopy.