Silver nanoparticles-decorated and mesoporous silica coated single-walled carbon nanotubes with an enhanced antibacterial activity for killing drug-resistant bacteria

The mounting threat of antibiotic-resistant bacterial infections has made it imperative to develop innovative antibacterial strategies. Here we propose a novel antibacterial nanoplatform of silver nanoparticles-decorated and mesoporous silica coated single-walled carbon nanotubes constructed via a N-[3-(trimethoxysilyl)propyl]ethylene diamine (TSD)-mediated method (SWCNTs@mSiO₂-TSD@Ag). In this system, the outer mesoporous silica shells are able to improve the dispersibility of SWCNTs, which will increase their contact area with bacteria cell walls. Meanwhile, the large number of mesopores in silica layers act as microreactors for in situ synthesis of Ag NPs with controlled small size and uniform distribution, which induces an enhanced antibacterial activity. Compared with TSD modified mesoporous silica coated single-walled carbon nanotubes (SWCNTs@mSiO₂-TSD) and commercial Ag NPs, this combination nanosystem of SWCNTs@mSiO₂-TSD@Ag exhibits much stronger antibacterial performance against multi-drug-resistant bacteria Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in vitro through damaging the bacterial cell membranes and a fast release of silver ions. Furthermore, the in vivo rat skin infection model verifies that SWCNTs@mSiO₂-TSD@Ag have remarkably improved abilities of bacterial clearance, wound healing promoting as well as outstanding biocompatibility. Therefore, this novel nanoplatform indicates promising potentials as a safe and powerful tool for the treatment of clinical drug-resistant infections.