Anti-Pseudomonas aeruginosa phage-loaded electrosprayed lactose particles

In light of the growing issue of antibiotic resistance, this study explored phage encapsulation within lactose particles for potential use in treating oral and ear bacterial infections. Firstly, phage-loaded suspensions that ensured phage stability at RT for 24 h were developed. After electrospraying, phage-loaded particles were successfully generated with an encapsulation efficiency (EE) of 31 % at a phage stock concentration of 50 % v/v. The phage titer decreased only slightly from 5 × 10 7 PFU/mg to 1.5 × 10 7 PFU/mg after processing, maintaining the same order of magnitude. The particles exhibited spherical morphology and successful phage encapsulation, with a burst release of phages within 10 min of immersion in an aqueous medium (99.0 ± 6.9 %). The phage-loaded particles demonstrated enhanced antibacterial efficacy compared to pure phage solutions, completely inhibiting P. aeruginosa growth for over 24 h at a particle concentration of 20 mg/ml, likely due to a high localized phage concentration. Stability studies indicated that phages remained viable at various temperatures, with greater stability at lower temperatures (4 °C, and −20 °C), though phage activity gradually decreased over time in particle form, particularly at room temperature.