DNA-directed electrochemiluminescence nanosphere with electrocatalysis-enhanced microfluidic arrays for rapid multibacterial detection

Rapid detection of multibacterial pathogens is crucial for accelerating the diagnosis and treatment of bacterial infections. We propose a rapid and efficient electrochemiluminescence (ECL) sensor for the synchronous detection of multiple bacterial pathogens, including <i>Staphylococcus aureus</i>, <i>Klebsiella pneumoniae</i>, <i>Pseudomonas aeruginosa</i>, and methicillin-resistant <i>S. aureus</i>. This homogeneous sensor is based on a self-assembled DNA nanosphere loaded with tetrakis (4-carboxyphenyl) porphyrin (TCPP). The sensor operates in an "off-on" mode, in which bacterium-aptamer binding triggers a conformational change in the DNA nanosphere, releasing TCPP and generating an enhanced ECL signal. The inclusion of cerium nanoparticles boosts signal intensity through electrocatalytic reactions, improving sensitivity with a detection limit of ≤100 colony-forming units per milliliter. Integrated with a microfluidic chip, the system enables multibacterial detection in just 45 minutes. Bacterial quantification in clinical samples strongly correlates with digital polymerase chain reaction results. This approach provides a rapid, specific, and efficient diagnostic tool for bacterial infections with great potential for point-of-care applications in clinical settings.