Bone Fillers with Balance Between Biocompatibility and Antimicrobial Properties

Millions of people request bone regeneration every year, and the market for bone grafting materials has a positive trend. The most used biomaterials applied to replace and regenerate bone are based on collagen and different types of ceramics in order to mimic natural bone matrix. However, there are a lot of implant-associated infections after surgery, or the implants are rejected because of reduced biocompatibility, and this is why the research into graft bone materials is still a challenge. This study aims to develop and characterize novel biomimetic bone fillers which have simultaneously both antimicrobial properties and biocompatibility with human bone marrow-derived mesenchymal stem cells (BMSCs). Type I collagen and calcium triphosphate in a ratio of 1:1 were used as a control, according to our previous studies, and ZnO, functionalized with different percentages of Satureja thymbra L. essential oils, was added as an antimicrobial, promoting bone growth, mineralization, and formation. The bone fillers were obtained by freeze-drying in spongious forms and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), water uptake, biodegradability over time, antimicrobial activity against Staphylococcus aureus and Escherichia coli and viability and proliferation of human BMSCs. The graft material showed a higher porosity with interconnected pores, gradual resorption over time and a balance between antimicrobial properties and biocompatibility and was chosen as an ideal bone filler.