Enhanced exosome capture in urine using aptamer-modified temperature-responsive polymer for sensitive early detection of bladder cancer

Current methods for bladder cancer (BCa) detection are often invasive and yield unsatisfactory diagnostic performance, especially for low-grade and early-stage tumors. Exosome biomarkers in urine offer excellent potential for improving the non-invasive early diagnosis of BCa. However, the lack of an efficient exosome isolation strategy poses a challenge for clinical application. This study presents a strategy for homogeneous exosome capture to enhance enrichment efficiency. We decorated exosome-specific aptamers onto a temperature-responsive polymer. Subsequently, leveraging the thermoresponsive properties of the polymer, which can transition between homogeneous and heterogeneous states at different temperatures, we achieved efficient homogeneous capture and rapid heterogeneous separation of urinary exosomes. The procedure, conducted at a relatively low temperature, enables rapid exosome isolation (within 5 min) without ultracentrifugation, facilitating clinical application. The developed exosome enrichment method using the functionalized temperature-responsive polymer offers significant advantages: an efficient, rapid, low-cost method that is widely applicable. Exosomes from urine samples, enriched using a functionalized temperature-responsive polymer, established a diagnostic model, exhibiting significant improved sensitivity over fluorescence in situ hybridization (FISH), particularly for early-stage (88.7% vs. 49.1%) and low-grade BCa (82.6% vs. 26.1%). This non-invasive, reliable BCa detection method holds promising potential for clinical use.