Preparation of pH-Responsive Chromogenic Nanoreagent for the Diagnosis of Ovarian Cancer.

Detection of extracellular vesicle (EV) membrane proteins is vital for both basic research and clinical diagnostics of ovarian cancer (OC). However, current methods suffer from complexity, high cost, and demanding operation. Herein, utilizing fetal bovine serum (FBS) as a natural carrier, a pH-responsive chromogenic nanoparticle with high curcumin (CUR) loading capacity and good dispersion is prepared, which is further employed as an EV probe for colorimetric biosensing. The proposed sensing strategy integrates TiO2-coated magnetic beads for efficient EV isolation, followed by specific labeling of EV membrane markers with chromogenic probes. Subsequent rapid pH-triggered CUR release generates a measurable signal, enabling the simple and sensitive analysis of EV proteins. This strategy is further validated in cell lines and clinical plasma samples, demonstrating its clinical utility and advancing EV biomarker identification and applications.