Improvement of in vitro osteogenesis and anti-infection properties by GelMA scaffold containing levofloxacin nanoparticles and strontium microspheres for osteomyelitis

Biomaterials that have capacities to simultaneously induce bone regeneration and kill bacteria are in high demand because bone defects face risks of severe infection in clinical therapy. The aim of this study was to investigate the use of gelatin methacryloyl (GelMA), alginate, gelatin hydrogels containing levofloxacin loaded poly (lactic-co-glycolic acid) nanoparticles (LEV-PLGA NPs) as antibacterial agent and strontium loaded PLGA microspheres (Sr-PLGA microspheres) as osteoinductive agent, intended for improving the treatment of osteomyelitis. Nanoparticles and microspheres were prepared using oil-in-water (o/w) and water-in-oil-in-water (w/o/w) emulsion method, respectively. Then GelMA-alginate-gelatin scaffold loaded with both LEV-PLGA NPs and Sr-PLGA microspheres, was prepared by UV radiation crosslinking. The mechanical strength of the GelMA scaffold was increased to 0.1 MPa by introducing gelatin and alginate into the GelMA hydrogel. The highest cumulative drug release from the LEV-PLGA-loaded hydrogels reached 64% over 25 days. The LEV-PLGA-NPs had an effective antibacterial response against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Furthermore, the performance in terms of cell viability had no adverse influence upon the absence of cytotoxicity, as indicated in tests carried out using normal adult human fibroblast cells. The presence of Sr-PLGA microspheres led to upregulation of RUNX2, Osteonectin, and Osteocalcin genes about 10, 9, and 10 times higher than control group in osteogenic differentiation of MC3T3 cells, respectively. Alkaline Phosphatase activity was 59 u/l on day 21. It could therefore be concluded that scaffold might be considered as a potential useful biomaterial for the treatment of osteomyelitis with antibacterial properties.

Automated summary

In this study, GelMA-alginate-gelatin scaffold loaded with antibacterial and osteoinductive agents showed promising potential for the treatment of osteomyelitis.