A portable smartphone-based fluorescence biosensing strategy for exosome detection.

Exosomes play a crucial role in intercellular communication and have emerged as promising biomarkers for disease diagnosis and prognosis, however, their nanoscale size and low abundance in biological fluids pose substantial challenges for rapid and quantitative detection. Conventional detection techniques rely on bulky instrumentation and complex workflows that hinder point-of-care implementation. Here, we report a portable smartphone-based fluorescence sensing platform specifically designed to address the limitations of existing exosome assays in portability, quantitative robustness, and operational simplicity. Exosome capture was achieved through a CD63-specific aptamer, followed by molecular recognition using a FAM-labeled, tumor-specific aptamer. A miniaturized optical readout device integrating an excitation unit, optical filters, and an imaging module enables fluorescence acquisition and quantitative analysis without large laboratory equipment. The system completes exosome detection within 45 min and achieves a limit of detection of 4.58 × 106particles/ml. Clinical sample analysis preliminarily demonstrates the feasibility of serum exosome detection using this portable platform, suggesting its potential utility for rapid, on-site biomedical screening.