Amplification-free light-activated CRISPR/Cas12a system with nano-amplifier for quantitative detection of non-nucleic acid targets.

Quantitative amplification-free CRISPR/Cas diagnosis to non-nucleic acid clinical biomarkers is limited by inefficient signal conversion and suboptimal sensitivity. Here, we present a light-activated CRISPR/Cas12a biosensing platform (LANA) to response this challenge. The LANA arms with a cascade signal enhancing strategy that integrates immunomagnetic enrichment, aptamer-functionalized gold nanoparticles carrying photocleavable activators, and UV-triggered release of activators to initiate Cas12a trans-cleavage. This light-controlled mechanism overcomes steric hindrance caused by surface confinement, provides precise temporal control of signal initiation, and effectively suppresses background activation. Using cardiac troponin I (cTnI) as a model analyte, LANA achieved a detection limit of 50 pg/mL, a wide dynamic range of 0.05-500 ng/mL, demonstrating high sensitivity and reliable quantitative performance with a simple fluorescence readout. Owing to its modular and amplification-free design, the platform can be readily adapted to other protein or small-molecule biomarkers, offering a generalizable and amplification-free framework for sensitive detection of non-nucleic acid targets.