Lactoferrin-Loaded Alginate Microparticles to Target Clostridioides difficile Infection

Some forms of bovine lactoferrin (bLf) are effective in delaying Clostridioides difficile growth and preventing toxin production. However, therapeutic use of bLf may be limited by protein stability issues. The objective of this study was to prepare and evaluate colon-targeted, pH-triggered alginate microparticles loaded with bioactive bLf and to evaluate their anti-C difficile defense properties in vitro. Different forms of metal-bound bLf were encapsulated in alginate microparticles using an emulsification or internal gelation method. The microparticles were coated with chitosan to control protein release. In vitro drug release studies were conducted in pH-simulated gastrointestinal conditions to investigate the release kinetics of encapsulated protein. No significant release of metal-bound bLf was observed at acidic pH; however, on reaching simulated colonic pH, most of the encapsulated lactoferrin was released. The application of bLf (5 mg/mL) delivered from alginate microparticles to human intestinal epithelial cells significantly reduced the cytotoxic effects of toxins A and B as well as bacterial supernatant on Caco-2 and Vero cells, respectively. These results are the first to suggest that alginate-bLf microparticles show protective effects against C difficile toxin-mediated epithelial damage and impairment of barrier function in human intestinal epithelial cells. The future potential of lactoferrin-loaded alginate microparticles against C difficile deserves further study.