Lactobacillus buchneri S-layer protein-coated liposomes loaded with β-cyclodextrin–carvacrol inclusion complexes for the enhancement of antibacterial effect

Abstract

This article describes the development of a novel liposome nanocarrier system. Carvacrol (Car) is first embedded in β-cyclodextrin (β-CD) by the freeze-drying method to form the β-cyclodextrin-carvacrol inclusion compound (β-CD–Car), and then β-CD–Car liposomes (β-CD–Car-LPs) and β-CD–Car liposomes coated with S-layer proteins (SLPs) from Lactobacillus buchneri 20023 (SLP/β-CD–Car-LPs) were prepared. The liposomes were characterized, and their stabilities, in vitro release characteristics, and antibacterial activities were investigated. Results showed that the fabricated liposome SLP/β-CD–Car-LPs was nanosized, oval and homogenous, with the particle size of 229.1 ± 6.81 nm, the polydispersity index of 0.139, and the zeta potential of 27.9 mV. Measurements based on Triton X-100 resistance indicated that the SLP-coated liposomes were more stable than naked liposomes. The in vitro release study results showed that the rate of release from SLP-coated liposomes was much lower than that from uncoated liposomes. The minimum inhibitory activity (MIC) of SLP/β-CD–Car-LPs (0.05 mg/mL) was 6.4 times higher than that of the free carvacrol (0.32 mg/mL) and was twice that of β-CD–Car-LPs (0.1 mg/mL). In general, the stability, antibacterial activity, and sustained release effect of β-CD–Car-LPs modified with SLPs were improved. Findings suggested that SLP-coated liposomes could be developed as a favorable delivery system for potential applications in the food industry.