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

Area of Science:

• Biotechnology
• Microfluidics
• Biosensing

Background:

• Conventional bacterial detection methods (culture-based, nucleic acid amplification) are complex, time-consuming, and costly.
• Limitations hinder the application of current methods in point-of-care (POC) diagnostics.
• Need for rapid, sensitive, and cost-effective bacterial detection platforms.

Purpose of the Study:

• To develop a novel fluorogenic DNAzyme (FDz)-based biosensor for rapid bacterial detection.
• To integrate FDz with a photonic-crystal-assisted microfluidic biochip (PC-μchip) for enhanced signal amplification.
• To evaluate the diagnostic performance of the developed PC-μchip for *Escherichia coli* (*E. coli*) detection.

Main Methods:

• Development of a microfluidic biochip incorporating serpentine channels, magnetic bead enrichment, and photonic crystal (PC) modules.
• Utilized fluorogenic DNAzymes (FDz) that release fluorescent single-stranded DNAs (ssDNAs) upon bacterial recognition.
• Detection of released ssDNAs via signal amplification on the PC surface.

Main Results:

• Selective detection of *Escherichia coli* (*E. coli*) achieved with a low detection limit of 100 cfu mL^-1.
• The PC-μchip demonstrated high signal amplification due to photonic crystal integration.
• Clinical validation with 20 patient urine samples showed 100% specificity and sensitivity.

Conclusions:

• The developed PC-μchip with FDz offers a rapid and sensitive platform for bacterial detection.
• Achieved results within 55 minutes, demonstrating suitability for point-of-care applications.
• The technology shows significant potential for real-world clinical diagnostics and bacterial monitoring.