Affiliation:
1. Department of Chemistry The University of Texas at Austin 105 E 24th St. Austin TX 78712 USA
2. Department of Oncology Dell Medical School The University of Texas at Austin 1601 Trinity St. Austin TX 78712 USA
3. Department of Biochemistry The University of Texas at Austin 105 E 24th St. Austin TX 78712 USA
Abstract
AbstractWe report the development of a new class of protease activity sensors called DNA‐barcoded plasmonic nanostructures. These probes are comprised of gold nanoparticles functionalized with peptide‐DNA conjugates (GPDs), where the peptide is a substrate of the protease of interest. The DNA acts as a barcode identifying the peptide and facilitates signal amplification. Protease‐mediated peptide cleavage frees the DNA from the nanoparticle surface, which is subsequently measured via a CRISPR/Cas12a‐based assay as a proxy for protease activity. As proof‐of‐concept, we show activity‐based, multiplexed detection of the SARS‐CoV‐2‐associated protease, 3CL, and the apoptosis marker, caspase 3, with high sensitivity and selectivity. GPDs yield >25‐fold turn‐on signals, 100‐fold improved response compared to commercial probes, and detection limits as low as 58 pM at room temperature. Moreover, nanomolar concentrations of proteases can be detected visually by leveraging the aggregation‐dependent color change of the gold nanoparticles. We showcase the clinical potential of GPDs by detecting a colorectal cancer‐associated protease, cathepsin B, in three different patient‐derived cell lines. Taken together, GPDs detect physiologically relevant concentrations of active proteases in challenging biological samples, require minimal sample processing, and offer unmatched multiplexing capabilities (mediated by DNA), making them powerful chemical tools for biosensing and disease diagnostics.
Funder
American Cancer Society
Cancer Prevention and Research Institute of Texas