Antibacterial Defective-ZIF-8/PPY/BC-Based Flexible Electronics as Stress-Strain and NO₂ Gas Sensors

Intelligent wearable sensors play a crucial role in the detection of toxic gases and monitoring physiological signals, thereby effectively ensuring environmental and personal health safety. Nonetheless, achieving the requirements for antibacterial properties, comfortable wear, and multifunctional detection remains a major challenge. In this study, a novel Def-ZIF-8/PPY/BC-based flexible sensor is developed by in situ growth of zeolitic imidazolate frameworks-8 (ZIF-8) and polypyrrole (PPY) on bacterial cellulose (BC), followed by water immersion. The Def-ZIF-8/PPY/BC-based flexible sensor demonstrates effective dual-sensitivity responses to nitrogen dioxide (NO2) toxic gas and stress-strain behaviors at room temperature. The structural characterization and theoretical calculations affirm that the innovative water treatment method successfully introduces defects into ZIF-8, resulting in a significant 2.57-fold improvement in response intensity to 80 ppm NO2. Stress-strain sensing performance analysis reveals that the Def-ZIF-8/PPY/BC-based flexible sensor exhibited high sensitivity (6.44 kPa(-1)), rapid response and recovery times (0.7/0.4 s), and exceptional cyclic stability (8000 cycles). Further, the inhibitory effect of ZIF-8 on common bacterial strains contributes to the exceptional antibacterial properties (antibacterial rate exceeding 99%) of the Def-ZIF-8/PPY/BC based on the flexible sensor. This study offers a significant advancement in metal-organic framework defect engineering and provides an effective strategy for developing multifunctional wearable sensors.