Benzalkonium chloride modified kaolinite with rapid bactericidal activity for the development of antibacterial films

Staphylococcus aureus ( S. aureus ) is one of the culprits responsible for hazardous wound infections and food contamination, and unrestrained antibiotic use has led to its widespread drug resistance. To tackle this issue, kaolinite (KAO) was modified with benzalkonium chloride (BAC) by a dry modification process to produce a material (BAC/KAO) that exhibits “rapid + persistent” bactericidal ability, coupled with organic compatibility. A “win-win” system between BAC and KAO was designed so that KAO increases BAC’s thermal stability while ensuring a proper release of BAC through an appropriate binding force. The modification of BAC provides KAO with antibacterial efficacy and enhances its organic compatibility. BAC/KAO has a minimum inhibitory concentration of 23.44 mg/L and an antibacterial rate of 92.61% against S. aureus . BAC/KAO is advantageous as it can rapidly kill over 60% of bacteria within the first 10 min and continue to inactivate the remaining bacteria, making it more desirable for practical applications. During the antibacterial process, both the released and unreleased BAC can inactivate S. aureus by interacting with its surface. Meanwhile, in vitro cytotoxicity assays confirm the potential of BAC/KAO for safe application. Furthermore, 30 wt% of doped BAC/KAO remains evenly dispersed in the poly(vinyl alcohol) film, resulting in an 11.295 mm inhibition zone. Therefore, BAC/KAO exhibits excellent promise as an alternative to antibiotics and for manufacturing antibacterial films for food packaging and wound dressings to combat S. aureus infection.