Integrating Fluorogenic DNAzymes with Photonic Crystals for Bacterial Detection on a Microfluidic Biochip

Conventional bacterial detection relies on culture-based methods and nucleic acid amplification. These multistep procedures increase complexity, processing time, and cost, limiting their utility in point-of-care (POC) diagnostics. To address this, we developed fluorogenic DNAzymes (FDz) for rapid bacterial detection on a photonic-crystal-assisted microfluidic biochip (PC-μchip). The biochip combines serpentine channel reaction, magnetic bead enrichment, and photonic crystal (PC) signal amplification modules. Upon bacterial recognition, FDz releases fluorescent single-stranded DNAs (ssDNAs), which flow onto the PC surface for enhanced signal output, enabling the selective detection of Escherichia coli (E. coli) with a detection limit of 100 cfu mL^-1. Clinical validation using 20 patient urine samples demonstrated 100% specificity and sensitivity within 55 min, highlighting its potential for real-world diagnostic applications.