Identification and diagnostic evaluation of an aptamer targeting prostate-cancer-derived small extracellular vesicles

Prostate cancer (PCa) lacks convenient, non-invasive, and highly specific diagnostic markers. Aptamers have emerged as preferred probes for biosensors that target extracellular vesicles (EVs). This study aimed to explore the diagnostic value of PCa-specific EVs aptamer probes. We used EV-SELEX to identify aptamers that selectively target PCa small EVs (sEVs). Surface plasmon resonance (SPR) and nanoflow cytometry were used to verify aptamer affinity. The diagnostic value of PCa was evaluated using clinical samples from patients. We screened and validated an aptamer, seq25, which exhibited high specificity for PCa-derived sEVs. The SPR assay revealed a strong binding affinity, with a KD of 24.02 nM and a dose-dependent binding response. Nanoflow cytometry demonstrated that seq25 could distinguish sEVs from PCa and normal prostate cell lines. In clinical specimens, the proportion of seq25-positive sEVs isolated from urine samples was significantly higher in patients with PCa than in those with benign prostatic hyperplasia. Our study integrated the diagnostic advantages of EVs with the technical benefits of aptamers to develop a PCa-specific sEVs aptamer probe that offers a promising non-invasive approach for PCa diagnosis.