dCas9-Fusion Peptide Library Display and DNA-Templated Peptide Microarray Self-Assembly for Quantitative Protein Binding Assays

CRISPR-based technologies have primarily been deployed for applications in gene editing and DNA/RNA detection. Here, we develop a CRISPR-inspired peptide display platform by fusing customized peptide libraries to nuclease dead Cas9 (dCas9) and pairing each dCas9-peptide fusion with a unique guide RNA (gRNA) barcode. After purification from a single batch of E. coli, each dCas9-peptide fusion within the mixture self-assembles to the position on a DNA microarray surface harboring a sequence complementary to its gRNA barcode. The resulting DNA-templated peptide microarrays are used for antibody binding studies with patient blood samples. dCas9-display may be further adapted for rapid diagnostics or biological materials assembly using DNA scaffolding.