Fenton reaction-assisted photodynamic inactivation of calcined melamine sponge against Salmonella and its application

Photodynamic inactivation (PDI) is an effective alternative to traditional antibiotics to broadly kill bacteria. This study aimed to develop a potent PDI system by coupling calcinated melamine sponges (CMSs) with the Fenton reaction. The results showed that CMS calcined at 350 ℃ was successfully carbonized with intact and porous structures, and it possessed excellent hydrophilicity and photothermal conversion performance. When Fe 2+ was added and internalized, the Fenton reaction in which Fe 2+ reacted with H 2 O 2 in cells occurred to produce reactive oxygen species (ROS) ( OH, OOH, etc.) and O 2 , and notably, the O 2 molecules could serve as a raw material to absorb the photothermal energy of CMS to generate highly reactive 1 O 2 . Under synergistic effects, CMS-350 coupled with Fe 2+ potently inactivated > 6 Log CFU/mL (>99.9999%) of Salmonella under 201.6 J/cm 2 blue LED illumination by destroying Na + /K + -ATPase and Ca 2+ /Mg 2+ -ATPase, DNA synthesis-related enzymes, cell membranes, etc. Meanwhile, the composite photocatalyst was proven to be nontoxic and could inactivate Salmonella in various foods, including vegetables ( Brassica chinensis L), eggs and fresh cucumber juice. As a result, CMS coupled with the Fenton reaction greatly improves the inactivation potency of PDI against harmful bacteria.