CRISPR/cas-based biosensors for point-of-care testing: a comprehensive review of signal readout strategies

The CRISPR/Cas system has emerged as a transformative tool for nucleic acid detection, offering significant potential for point-of-care testing (POCT). However, translating CRISPR/Cas-based assays into practical POCT devices critically depends on the development of portable, sensitive, and user-friendly signal readout modalities. This review systematically compares four major readout modalities: fluorescence, electrochemical, colorimetric, and distance‑based readout, analyzing their mechanisms, analytical performance, and practical limitations. Key challenges, including sample preparation, amplification-free detection, multiplexing, and commercialization barriers, are critically assessed. Finally, future perspectives are proposed: integrating microfluidics with smartphone‑based readout, leveraging artificial intelligence and the Internet of Things for automated signal interpretation and cloud connectivity, and establishing regulatory pathways for clinical translation. This review aims to provide actionable insights for researchers developing next‑generation CRISPR diagnostics and to accelerate the transition from laboratory prototypes to deployable POCT devices.