Erasable FAP Targeted Spray‐On Probe for Fluorescence‐Guided Surgery

ABSTRACT Fluorescence‐guided surgery is an emerging clinical field that aims to improve cancer detection in real‐time, enabling spot‐on therapeutic decisions. The use of fluorescent affinity probes has primarily involved systemically injected probes and, more recently, “spray‐on probes”. A current challenge has been to develop “turn‐off” probes that can be inactivated by a UV light pulse and reduce background noise during iterative decision‐making. Here, we report on the first development of a FAP‐targeted erasable spray‐on probe (ESOP). The probe consists of three components: (i) a highly bright, yellow light‐emitting rhodamine dye, (ii) a photo‐responsive linear triazene linker, and (iii) a FAP affinity ligand. We demonstrate that this probe could enable highly sensitive tumor‐specific margin visualization within minutes after a spray‐on application. Moreover, we show that the fluorescent signals could be fully erased with a 2‐min UV‐light pulse in tissue, permitting iterative staining applications with consistently high tumor‐to‐background ratios (TBRs). ESOP targeted against cancer or host tissue is feasible and is likely to yield transformative impacts on next‐generation cancer surgeries, ultimately improving patient care.