Stearyl polyoxyethylene ether‐grafted chitosan nanoparticles for improving the antibacterial property of tetracycline

In this study, a grafted copolymer based on chitosan and Brij S100 (CTS–Brij S100) was prepared to design a nanocarrier system that increases the sensitivity of tetracycline (Tetra) against methicillin‐susceptible Staphylococcus aureus (MSSA). The self‐assembly behavior of CTS–Brij S100 to micelles was confirmed by the benzoylacetone assay. About 4.6 ± 0.175% of Tetra was encapsulated into CTS–Brij S100 with an efficiency of 96.9 ± 0.213%. Dynamic light scattering determined the size of Tetra‐loaded nanoparticles (CTS–Brij S100@Tetra) to be 85.5 ± 1.913 nm with narrow distribution. The high‐positive value of CTS–Brij S100@Tetra (zeta = + 30.9 mV) indicates a stable colloidal system. The release profile of Tetra from CTS–Brij S100 followed the Weibull model with a complex diffusion mechanism. The bactericidal efficacy was tested against MSSA. Interestingly, the blank CTS–Brij S100 nanoparticle could express its inhibition to MSSA when the concentration was 150 μg/mL. Therefore, with the help of CTS–Brij S100, Tetra had superior bactericidal efficiency comparable to free form. In vitro biocompatibility test on fibroblast cells (L929) and bone marrow mesenchymal stem cells (BMSCs) ensures the safety of CTS–Brij S100. It can be concluded that the CTS–Brij S100 system holds potential for applications in facilitating the delivery of the antibiotic Tetra.