Engineered biopolymer-ZIF-8 composites for bacterial aerosols sampling and detection

Bacterial aerosols, a major infectious disease transmission route, require effective capture, inactivation, and detection. Most air filters provide high-efficiency filtration but lack efficient target recovery and rarely integrate inactivation with downstream analysis. Herein, a monolithic ZIF-8-based foam coupled with a nanozyme-assisted colorimetric biosensor was developed for bacterial aerosol sampling, recovery, and detection. A polysaccharide ZIF-8-based foam (PC-ZIF-8 foam) was used to efficiently capture and concentrate airborne bacteria. The foam was then dissolved in phosphate-buffered saline (PBS) to release the captured bacteria, thereby enabling direct downstream analysis. Meanwhile, zinc ions (Zn^2 +) released during dissolution contributed to bacterial inactivation, which enhanced biosafety during subsequent sample handling. Besides, a colorimetric biosensor based on Fe-ZIF-8 nanozymes was used for detection of the captured bacteria. This system achieved high performance: > 99.95% capture efficiency for 0.3-1 μm bacterial aerosols at 4 L/min while only causing low pressure drops (<35 Pa), > 99.99% bacterial inactivation within 15 min, and a low detection limit of 117 CFU/m³ in 90 min. This work provided a practical platform for integrated bacterial aerosol sampling and detection with improved recovery and operational safety.