Antibiotic loaded solid lipid nanoparticles target bacteria in a pyogenic spondylitis rat model.

Authors

Min Je Kim, Gong Ho Han, Wan-Kyu Ko, Seong Jun Kim, Daye Lee, Gi-Beom Ju, Seung Hun Sheen, Je Beom Hong, Seil Sohn

Published in

Discover nano. Volume 21. Issue 1. Aug 06, 2026. Epub Aug 06, 2026.

Abstract

Pyogenic spondylitis is treated with high-dose antibiotics for at least six weeks. In this study, we aimed to develop a novel therapeutic agent that can enhance bacterial targeting. We used solid lipid nanoparticles (SLNs) containing the antibiotic ampicillin (AMP), which were functionalized with the positively charged peptide LL-37. AMP-loaded SLNs (AMP-SLNs) were prepared, and LL-37 was attached to the AMP-SLNs (LL-37@AMP-SLNs). The physicochemical properties of the nanoparticles were characterized by particle size, zeta potential, morphology, drug release behavior, and hemocompatibility analyses. Furthermore, antibacterial activity, bacterial-targeting capability, and therapeutic efficacy were evaluated using Enterococcus faecalis-infected mesenchymal stem cells and a rat model of pyogenic spondylitis. The antibacterial performance of LL-37@AMP-SLNs was compared with that of SLNs and AMP-SLNs. The average size of the SLNs was approximately 342.66 ± 48.04 nm, which increased to 528.58 ± 35.64 nm after AMP loading and 695.58 ± 75.58 nm following LL-37 modification. The LL-37@AMP-SLNs exhibited sustained AMP release over four days and demonstrated enhanced antibacterial activity and bacterial-targeting capability compared with unmodified SLNs and AMP-SLNs. LL-37@AMP-SLNs were shown to inhibit bacterial growth by targeting the cytoplasmic membrane and the cell walls of Gram-positive bacteria. Moreover, the LL-37@AMP-SLNs treatment led to significantly enhanced antibacterial effects. In vitro studies showed significantly greater inhibition of bacterial growth, while intravenous administration of LL-37@AMP-SLNs significantly reduced bacterial burden and improved therapeutic outcomes in the pyogenic spondylitis rat model compared with free AMP treatment. We suggest that LL-37@AMP-SLNs can be a useful therapeutic agent for targeting bacteria in pyogenic spondylitis.

PMID:
42560613
Bibliographic data and abstract were imported from PubMed on 06 Aug 2026.

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