MOF-based controlled-release patches for nitric oxide: fabrication, gas release profile, and preservation efficacy on cherry tomatoes.

Nitric oxide (NO) preservation suffers from instability and safety issues via conventional single-exposure treatments, while wet-casting methods cause substantial NO donor loss. This study developed metal-organic framework (MOF)-mediated controlled-release patches to address these limitations. Three MOFs (Cu-MOF, Zn-MOF, Fe-MOF) with distinct pore structures were synthesized, achieving 26.9%-38.2% L-arginine loading. The resulting gelatin-polyacrylic acid sodium hydrogel patches exhibited tensile strength of 3.03-4.84 MPa and elongation at break of 131.3%-240.1%, and dissolution rates of 12.4%-17.2%. They also showed significant antimicrobial activity against E. coli, S. aureus, and A. niger. MOF loading elevated precursor utilization efficiency to 70%-82.5%. The patches achieved sustained release of H₂O₂ (8.0-9.6 mmol/g) and NO (41.7-50.6 ppm) over 12 days, extending cherry tomato shelf life to 12 days at room temperature while maintaining total bacterial levels within safe limits. This work establishes MOF-mediated controlled release for green preservative gas utilization.