Multivariate 'AND-gate' substrate probes as enhanced contrast agents for fluorescence-guided surgery

Abstract

The greatest challenges for surgical management of cancer are precisely locating lesions and clearly defining the margins between tumors and normal tissues. This is confounded by the characteristics of the tissue where the tumor is located as well as its propensity to form irregular boundaries with healthy tissues. To address these issues, molecularly targeted optical contrast agents have been developed to define margins in real-time during surgery1,2. However, selectivity of a contrast agent is often limited by expression of a target enzyme or receptor in both tumor and healthy tissues. Here we introduce a concept of multivariate AND-gate optical imaging probes that require sequential processing by multiple tumor-specific enzymes to produce a fluorescent signal. This results in dramatically improved specificity as well as overall enhanced sensitivity. This general approach has the potential to be broadly applied to selectively target complex patterns of enzyme activities in diverse disease tissues for detection, treatment and therapy response monitoring.