Intracellular biosensors by functional nanomaterial-integrated CRISPR technologies for real-time molecular sensing

CRISPR technology, originally developed as a genome-editing tool, has recently emerged as a powerful platform for intracellular biosensing. By harnessing the programmability and target specificity of CRISPR-associated proteins, such as Cas9, Cas12, and Cas13, researchers have engineered biosensors capable of detecting a wide array of intracellular signals, including nucleic acids, non-coding RNAs, and small-molecule metabolites. This review discusses the recent advancements in CRISPR-powered biosensors for real-time, dynamic monitoring of cellular processes and molecular events. Particular focus is given to the integration of nanotechnology, which plays a crucial role in enhancing the delivery efficiency, signal amplification, and sensor stability. Nanomaterials such as gold nanoparticles, quantum dots, DNA nanostructures, and upconversion nanoparticles have been strategically employed to improve the intracellular transport of CRISPR components, facilitate signal readouts, and enable multimodal sensing in complex cellular environments. Additionally, we delve into how CRISPR-nanotechnology hybrids can be adapted for multiplex analysis and single-cell resolution. This review also addresses the current challenges in intracellular biosensing, including precise delivery, biocompatibility, and long-term monitoring, and outlines future directions for the application of these systems in precision medicine, synthetic biology, and advanced therapeutic monitoring. Through the convergence of gene-editing systems and nanotechnology, CRISPR-based intracellular biosensors are anticipated to revolutionize next-generation diagnostic and therapeutic strategies.