In Situ and Rapid\nToxicity Assessment of Air Pollution\nby Self-Assembly Passive Colonization Hydrogel

Air pollution is a leading environmental health risk\nfactor, and\nin situ toxicity assessment is urgently needed. Bacteria-based bioassays\noffer cost-effective and rapid toxicity assessments. However, the\napplication of these bioassays for air toxicity assessment has been\nchallenging, due to the instability of bacterial survival and functionality\nwhen directly exposed to air pollutants. Here, we developed an approach\nemploying self-assembly passive colonization hydrogel (SAPCH) for\nin situ air toxicity assessment. The SAPCH features a core–shell\nstructure, enabling the quantitatively immobilization of bacteria\non its shell while continuously provides nutrients from its core.\nAn antimicrobial polyelectrolyte layer between the core and shell\nconfines bacteria to the air–liquid interface, synchronizing\nbacterial survival with exposure to air pollutants. The SAPCH immobilized\na battery of natural and recombinant luminescent bacteria, enabling\nsimultaneous detection of various toxicological endpoints (cytotoxicity,\ngenotoxicity and oxidative stress) of air pollutants within 2 h. Its\nsensitivity was 3–5 orders of magnitude greater than that of\ntraditional liquid-phase toxicity testing, and successfully evaluating\nthe toxicity of volatile organic compounds and combustion smoke. This\nstudy presents a method for in situ, rapid, and economical toxicity\nassessment of air pollution, making a significant contribution to\nfuture air quality monitoring and control.