In situ Synthesis of Zeolitic Imidazolate Framework-11@ZnO Heterostructures for Enhanced Antimicrobial Activity and Biological Preservation

Storage and transportation are critical processes that significantly affect food quality, with bacterial proliferation serving as a major contributor to deterioration. Preservative films are commonly used in food transportation and preservation. However, the approval process for contact-type preservative films remains challenging due to inconclusive toxicity assessments. In this work, we synthesized antimicrobial zeolitic imidazolate frameworks (ZIFs) with ZnO microtube heterostructures (ZZHs) for contactless biological preservation using the optical vapor phase supersaturated precipitation (OVSP) method, combined with an in situ solvothermal approach. This ZZH exhibited excellent antimicrobial activity and achieved efficiencies of 90.47% and 98.24% against E. coli and S. aureus, respectively. We also developed a highly flexible ZZH/PDMS film that demonstrated exceptional structural stability under various temperature, acid, and alkali conditions, which supported the potential for stable intrinsic antimicrobial activity. The hydrophilic nature and high specific surface area of the ZZH/PDMS film were beneficial to capture the dispersed water vapor, bacteria, and other harmful substances, which enhanced the efficiency of the antimicrobial functional sites. This strategy indirectly inhibited bacterial proliferation by controlling ambient humidity, thus avoiding direct contact between the film and the fruit. This process was defined as a contactless mechanism. This work offers an avenue for the development of highly flexible and durable antimicrobial heterostructure agents for contactless biological preservation in future applications.