Borate mineral loading into acrylic bone cements to gain cost-effectivity, enhanced antibacterial resistivity, and better cellular integration properties.

Polymethyl methacrylate (PMMA), called as bone cement, has been used in implant surgery, initially in dental practices, then in arthroplasty surgery for decades. Bone cement is a highly preferred chemical in the field of orthopedics due to its bone-like hardness and mechanical strength. Meanwhile, antibiotic-loaded cements are used in joints and similar surgeries are generally due to the risk of infection. In this study, we aimed to demonstrate the effects of borate mineral loading into bone cement on enhancing the antibacterial resistivity and cell integration as well as retaining mechanical properties. Moreover, the incorporation of minerals into bone cements makes them much more cost-friendly biomaterials for surgical operations. Herein, antibacterial properties were evaluated by using vancomycin- and gentamycin-susceptible strains of Enterococcus faecalis and Staphylococcus aureus whereas cell viability tests were performed by osteoblast cell lines. Three sets of the bone cements, plain, calcium borate-, and sodium borate-loaded, were prepared through commercial procedures and subjected to mechanical, antibacterial and cell viability tests. Percentage deformation determined by compression tests under 0.100 MPa pressure was determined in the range of 12.58%-10.67% in respect to the amount of sodium borate mineral loaded whereas that was determined in the range of 12.54%-9.87% in respect to the amount of calcium borate mineral loaded. Micro-CT results also supported good mineral integration and structural features of the composite bone cements. Furthermore, mineral incorporation enhanced the cell viability, in other words, cellular integrity, up to 101.28% for sodium borate-loaded (NB75, 7.5 g mineral) and 72.04% for calcium borate-loaded (CB75, 7.5 g mineral) bone cement according to the negative control group, fresh culture medium. As a conclusion, both of these minerals could be classified as promising alternatives for developing bone cements with better antibacterial resistivity and cellular integration properties.

Development of a Sequential Antibiotic Releasing System for Two-Stage Total Joint Replacement Surgery.

In recent years, there has been an increase in nanoparticle research towards creating better release systems that can maintains the effective dosage over desired periods. Conventional nanoparticle systems have not been successful for this goal. Thus, the aim of this study is to evaluate the sequential release profiles of hybrid materials, combining nanoparticles, hydrogels and bone cement, for the treatment of arthroplasty infections. In this study, Vancomycin, which is one of the most used antibiotics in orthopedics, was loaded to alginate-chitosan nanoparticles. These drug-loaded nanoparticles were dispersed in an alginate gel and the gel covered the polymethylmethacrylate bone cement. After the crosslinking of the gel around the bone cement, the sequential release profile was evaluated for 60 days in vitro. The results of the morphological, chemical characterization and encapsulations studies showed that different loadings of drugs resulted in different encapsulation efficiencies. Although the release profile from the nanoparticles was as expected, the sequential release profile of the combined system has a Fickian type release for a longer time period. In conclusion, the results indicate that combining different release systems can alter the release profile of the system.