One-pot self-assembly strategy to prepare mesoporous silica-based nanocomposites with enhanced and long-term antibacterial performance

Different from conventional polymer-modified antibacterial composites requiring multiple and complex synthesis processes, one-pot route was adopted in this work to prepare antibacterial nanocomposites (TTO@CTAB@MSNs) via a self-assembly strategy, which allowed the water-insoluble tea tree oil (TTO) to be encapsulated in the hydrophobic micelle core of cetyl trimethyl ammonium bromide (CTAB) within the nanochannels of mesoporous silica nanoparticles (MSNs). The chemical structures, pore structural parameters, and thermal stability of these nanocomposites were confirmed. It was found that, the obtained nanocomposites possessed a diameter below 600 nm with mesoporous structures. Although the increase in CTAB exerted slight influence on TTO content, it significantly enhanced the sustained release behavior of TTO. After continuously releasing for 8 h, the cumulative release rates only reached 20 %, and such release behavior followed the Zeroorder kinetic model. Besides, these nanocomposites exhibited remarkable antibacterial performance against E. coli and S. aureus even at a low concentration of 0.06 mg mL-1 due to the collaboratively antibacterial effects from CTAB and TTO. And they maintained antibacterial activity even after 45 days, indicative of the long-term antibacterial performance. Moreover, the antibacterial mechanism of these nanocomposites was also elucidated