CRISPR Assays for Protein Detection

The advent of CRISPR–Cas systems has reshaped molecular diagnostics by enabling programmable nucleic acid recognition and collateral cleavage–based signal amplification. Recently, these properties have been harnessed to extend CRISPR detection beyond DNA and RNA toward clinically relevant protein biomarkers. In this review, we summarize recent advances in CRISPR–Cas–based strategies for protein detection, focusing on two major modalities: recognition element–based and activity-based approaches. The first exploits molecular components such as antibodies, aptamers, and DNAzymes as transduction modules that convert protein binding events into CRISPR-readable nucleic acid inputs. The second leverages intrinsic protein activities such as enzymatic catalysis, nucleic acid processing, and substrate modification, to trigger CRISPR activation through rationally designed DNA or RNA probes. Together, these methodologies provide modular, scalable, and highly sensitive solutions for protein biosensing. By integrating advances in nucleic acid chemistry, nanotechnology, and molecular engineering, CRISPR-based protein diagnostics are rapidly evolving toward multiplexed, portable, and point-of-care formats. The combination of programmable nucleic acid recognition with biochemical versatility positions CRISPR systems as a next-generation analytical platform, bridging molecular biology and clinical diagnostics.