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The aim of the present study was to obtain and to investigate nano forsterite and nano forsterite biocomposites for biomedical application. New self-curing forsterite biocomposites were obtained by mixing nano forsterite powder (5, 15, 30, 50, 70 wt %) with 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane (bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) monomers. The new nano forsterite biocomposites were investigated for mechanical properties: compressive strength (CS) (143-147.12 MPa), compressive modulus (CM) (1.67-2.75 GPa), diametral tensile strength (DTS) (27.33-31.55 MPa), flexural strength (FS) (59.47-83.20 MPa) and flexural modulus (FM) (2.05-8.60 GPa). Increases of CS, DTS, FS with increasing amount of forsterite were observed up to 50 wt %. The highest CM and FM values were registered for 70 wt % and a direct correlation between the forsterite volume fraction (%) was observed. SEM micrographs revealed the morphology of surface of fractured biocomposites after CS test. XPS indicated that these biocomposites promoted the hydroxyapatite formation on their surface immersed in simulated body fluid (SBF). AFM images showed that the growth of the hydroxyapatite layer occurs with a preferred orientation on the surface of forsterite biocomposites after immersion in SBF. Incorporation of nano forsterite in the polymer matrix (bis-GMA/TEGDMA) did show osteoblast adhesion and proliferation was improved on nano forsterite biocomposites. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1290-1301, 2016.

There is a continuous need for discovering new nanomaterials with antibacterial activity against various pathogens, like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). This study was performed to assess the antimicrobial activity of two novel nanostructured forsterites, both in the absence and the presence of silver nanoparticles (AgNPs). The two nano forsterites (FS) were prepared by advanced sol-gel (FSsg) and precipitation (FSpp) methods. Preparation of colloidal AgNPs systems was realized by using the precursor, AgNO3, and the trisodium citrate and tanic acid assuring the formation and stabilization of AgNPs. The characterization of nano forsterite powders was carried out using complementary physical methods: XRD, SEM, and AFM. The AgNPs were characterized by UV-Vis spectra, STEM and AFM imaging. The antimicrobial activity was studied by the agar well diffusion method both in the FS native state, as FSsg and FSpp, and in their mixture with silver nanoparticles (AgNPs). The inhibitory effect of synthesized forsterites, FSsg and FSpp, particularly variants with AgNPs was found only on the S. aureus strain, the zones of inhibition being between 8 and 10 mm, and more intensely expressed in the FSpp-AgNPs dispersions. These findings open new orthopedic applications of these systems, particularly for antimicrobial coated metallic implants.

This study is aimed to evaluate the biocompatibility and bioactivity of some new porous forsterite ceramics (FCs) produced from high-purity nano forsterite powder, synthesized by an original sol-gel method, which was subjected to pressing into pellets, by using a poly vinyl alcohol solution as a binding component. Then, the raw pellets were sintered at 1200 �C, 1300 �C, 1400 �C and 1450 �C. The obtained four forsterite ceramics, FC-1200, FC-1300, FC-1400 and FC-1450, were fully characterized by density, porosity and shrinkage measurements. The forsterite ceramics exhibited excellent biocompatibility determined by an in vitro cell viability assay, such as MTT test. Furthermore, the in vitro bioactivity test was performed by immersing the forsterite ceramics into simulated body fluid (SBF) and examining the hydroxyapatite (HAP) formation on forsterite ceramics, as evidenced by XRD, FTIR, SEM with EDX. Moreover, the relationship between porous structure and bioactivity of forsterite ceramics in SBF as well as the performance of FC in a cell culture was evaluated. The findings strongly recommend these forsterite ceramics for biomedical applications, as potential bone substitutes.

Endodontic cement based on calcium silicate has been the focus of many studies. However, the quality of resulted endodontic cement needs improvement. This paper focuses on endodontic cement obtained from Portland cement enriched with two types of hydroxyapatite, simple and doped with 5% Zn. Hydroxyapatites were synthesized using a wet precipitation method and investigated by X-ray diffraction, FTIR, TEM and AFM. From a structural point of view, both hydroxyapatites were obtained in a single crystalline phase, containing particles in the nanometric range, as judged by XRD, TEM and AFM. FTIR analysis presents O-H and P-O bands specific to those in pure hydroxyapatite, confirming a hydroxyapatite lattice in both materials. Several experimental compositions of commercial Portland cement mixed with hydroxyapatite were prepared. The influence of stoichiometric and Zn doped hydroxyapatite on the resulted endodontic cement was observed in the setting time. The setting time for both cements decreased exponentially at both temperatures (22 ⁰C and 37 ⁰C). The normal consistency water remains constant for all experimented slurries.