Attapulgite-Assisted In Situ Anchoring of Ultrasmall Ag Nanoparticles for Enhanced Eradication of Multidrug-Resistant Bacterial Biofilms and Accelerated Wound Healing

Abstract

Silver nanoparticles (Ag NPs) have emerged as a promising solution to combat biofilm-related infections caused by multidrug-resistant bacteria. However, their practical application remains limited due to their tendency to aggregate and exhibit high toxicity at elevated concentrations. Here, we developed a Citrus limon peel water extract-mediated hydrothermal process to facilitate the heterogeneous nucleation of Ag NPs on attapulgite (APT) nanorods and prepared Ag/APT nanocomposites with ultrasmall Ag NPs (<2 nm) uniformly anchored on APT nanorods. Ascorbic acid and polyphenols in Citrus limon peel extract acted as electron donors to reduce Ag⁺ to Ag⁰, while the interfacial interaction of APT nanorods induced heterogeneous nucleation and confined the growth of Ag nanocrystals, resulting in ultrasmall Ag NPs. As a result, due to the synergistic effect of the targeted biofilm-binding affinity of APT nanorods and the siginificantly increased specific surface area of Ag NPs conducive to the release of Ag⁺ ions, the obtained Ag/APT nanocomposites exhibited enhanced eradication activities on antimicrobial-resistant bacterial biofilms and accelerated wound healing in MRSA-infected wound models. Additionally, attributing to the low dosage of Ag, Ag/APT exhibited exceptional biocompatibility both in vitro and in vivo. This work provides a simple and green strategy for the preparation of highly active Ag-based antibacterial nanomaterials and sheds new light on the development of advanced antimicrobial agents for wound healing.