Programmable CRISPR-mediated gold nanoparticle adhesion for visual colorimetric detection

While the aggregation behavior of gold nanoparticles (AuNPs) has been extensively studied in biosensing, catalysis, and nanomedicine, their potential for programmable surface adhesion via tunable surface chemistry remains largely untapped. Here, a programmable CRISPR-mediated hydrophobic adhesion phenomenon using streptavidin-coated AuNPs functionalized with Cy5-ssDNA-biotin probes is introduced. Hydrophobic Cy5 moieties on the AuNP surface induce localized aggregation and strong adhesion to hydrophobic surfaces. This unique behavior was leveraged by coupling CRISPR-Cas12a-mediated ssDNA cleavage with Cy5-labeled ssDNA-coated AuNPs to develop a simple, visual-readout colorimetric assay for nucleic acid detection. When combined with recombinase polymerase amplification, the method achieved ultrasensitive detection of human papillomavirus (HPV) DNA down to 10 aM, without the need for complex instrumentation. The platform's clinical utility was validated by detecting HPV DNA in cervical swab samples, highlighting its promise for low-cost, sensitive, and accessible point-of-care diagnostics in resource-limited settings. Unlike conventional aggregation-dispersion systems, this platform introduces a fundamentally distinct signal transduction mechanism based on surface adhesion, defining a new modality within CRISPR-based colorimetric diagnostics and offering a simple, low-cost solution for point-of-care testing.