DNA Logic-Gated CRISPR/Cas13a and PNTs-Hemin Biomimetic Nanozyme for Ratiometric Detection of BRCA1 and circROBO1

Although nanozyme-based biosensors show great promise for the early diagnosis of cancer, their application is often limited by poor catalytic activity at neutral pH and susceptibility to matrix interference. This study involved the construction of a biomimetic nanozyme through coordination-driven self-assembly on peptide nanotubes. This rigid framework enables the periodic arrangement of histidine residues to achieve precise axial coordination with the iron center of the hemin molecule, effectively mimicking the active site and catalytic microenvironment of natural horseradish peroxidase. Consequently, PNTs-hemin exhibits peroxidase activity 2.7 times that of free hemin under near-physiological conditions. To ensure detection specificity, an AND logic gate design was integrated, triggering CRISPR/Cas13a-mediated trans-cleavage only when both targets (BRCA1 and circROBO1) are present simultaneously. Furthermore, combining the nanozyme with graphdiyne-supported gold nanoparticles resulted in the formation of a cascade catalytic system that produced a ratiometric electrochemical reading (I_Fc/I_hemin). This effectively corrects for environmental fluctuations and false positive signals. This study presents an effective strategy that combines the specificity of molecular logic gates with biomimetic catalysis. This opens up new avenues for the precise diagnosis of multiple targets in complex biological samples.