Delivery LL37 by chitosan nanoparticles for enhanced antibacterial and antibiofilm efficacy

In this study, the fabrication of LL37-loaded chitosan nanoparticles (CS/LL37-NPs) was based on an ionotropic gelation method between sodium tripolyphosphate (TPP) and chitosan. Synthesized chitosan nanoparticles (CS-NPs) were approved by Fourier Transform Infrared (FTIR), UV-vis spectroscopy, Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), and Transmission Electron Microscopy (TEM). The encapsulation efficiency of LL37 in this delivery system (CS/LL37-NPs) was 86.9%. According to in vitro release profile, the release of LL37 from CS/LL37-NPs was almost complete after 5 days. Additionally, CS/LL37-NPs can cause an increase in the half-life and prolonged LL37 antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA). This delivery system demonstrated 68% biofilm formation inhibition compared to the LL37 alone. Also, icaA gene expression in the face of CS/LL37-NPs was significantly decreased. This study showed the important role of delivery systems in enhancing LL37 antibacterial and antibiofilm activity which can be suggested as a promising agent in the inhibition of bacterial growth and the prevention of biofilm formation.