Enzymatic Cascade-Powered Urinary Diagnostics for Visual Cancer Monitoring

Accurate, real-time, noninvasive longitudinal diagnostic tools are essential for guiding personalized cancer therapy, and urine-based platforms represent a promising noninvasive avenue for continuous therapeutic monitoring. However, conventional approaches relying on passive detection of tumor-derived biomarkers shed into urine are often limited by physiological instability, low abundance, and poor specificity. Herein, we present a dual-enzyme-powered nanosensor for urine-based diagnostics that integrates apurinic/apyrimidinic endonuclease 1 (APE1)-triggered strand cleavage and telomerase (TE)-mediated extension to amplify the signal, enabling visual detection of tumor-associated enzymatic activity via a lateral flow assay (LFA). The nanosensor is constructed by assembling gold nanoclusters (AuNCs) with a synthetic DNA probe (A1T2) and encapsulating the complex with hyaluronic acid (HA). The AuNCs exhibit intrinsic fluorescence and enhanced DNA stability, thereby enabling structural integrity and real-time monitoring. The A1T2 strand is engineered with recognition motifs for APE1 and TE, which mediate sequential DNA cleavage and extension under pathological enzyme overexpression. Upon activation, the nanosensor is enzymatically processed, leaving a AuNC-tagged short single strand that is excreted into urine and detected by a competitive LFA strategy. This enables direct, visual, and instrument-free readout. The synergistic action of APE1 and TE confers a competitive advantage on the DNA substrate, leading to enhanced chromogenic shifts on test strips and improved visual resolution. This strategy translates intracellular enzyme activity into stable urinary signals and demonstrates the potential for low-cost, instrument-free companion diagnostics for personalized cancer treatment.