Harnessing Plasmonic Cu2− x Se Transducers for Quantitative Near-Infrared II Photothermal Lateral Flow Exosome Detection

Abstract

Abstract Photothermal lateral flow assays (PT-LFAs) hold immense promise for advancing point-of-care (POC) diagnostics into the realm of robust, on-site quantitative analysis. However, their clinical translation remains fundamentally constrained by the absence of high-performance photothermal transducers and insufficient analytical sensitivity. Herein, we develop a near-infrared II (NIR-II) PT-LFA biosensor utilizing a NIR-II PT probe for the sensitive photothermal detection of glioblastoma-derived exosomes in serum. The NIR-II PT probe comprises silica-coated Cu2−xSe core−shell nanoparticles conjugated with anti-EGFR monoclonal antibodies. Numerical simulations and experimental investigations collectively demonstrate the superior NIR-II plasmonic and photothermal properties of the Cu2−xSe component within the probe. Integrating this NIR-II PT probe, the biosensor achieves a limit of detection of 0.62 × 107 particles/mL and a broad dynamic detection range of 0.8−1200 × 107 particles/mL via the NIR-II PT readout, markedly outperforming conventional colorimetric detection. Furthermore, the biosensor exhibits reliable detection accuracy and excellent robustness for exosome analysis in complex serum samples. This study underscores the substantial potential of Cu2−xSe photothermal transducers for the development of highly sensitive LFA-based POC diagnostic platforms.