Split CRISPR/Cas systems: Pioneering solutions for molecular diagnostics challenges

Split CRISPR/Cas systems have recently emerged as revolutionary tools in molecular diagnostics, addressing the limitations of conventional CRISPR-based detection methods, such as low sensitivity and specificity for low-abundance targets and limited regulatory flexibility. This review highlights "split-activation" strategies that enhance analytical performance without requiring pre-amplification. It elaborates on two key approaches: split activator-mediated Cas systems for ultrasensitive RNA detection and split crRNA architectures for multiplex nucleic acid analysis. These innovations achieve significant improvements in sensitivity for femtomolar-level biomarkers while maintaining superior single-base discrimination. We examine their applications in clinical and on-site monitoring, analyze current challenges including background noise, multiplex capacity, and cost considerations. Future directions include developing customized Cas variants, nanomaterial-based amplification-free workflows, and integrated microfluidic platforms. This technology holds great promise for precision diagnostics, particularly in resource-limited settings.