In this study, polymer blends between PEG-PPG-PEG copolymer mixtures and pregelatinized starch at various compositions ranging from 0 to 3 % by weight were prepared and evaluated for potential use as novel resorbable bone hemostatic wax. It was found that the prepared samples had sufficient smearability for use as a bone wax. An addition of pregelatinized starch increased the hardness, smoothness and consistency of the texture while decreasing the adherence to glove. Thermal analysis indicated that the heat of fusion slightly decreased with increasing pregelatinized starch content. Compressive stiffness tended to decrease with increasing starch content for concentrations lower than 20 %, but re-increased at higher starch levels. In contrast, adherence deformation increased initially, but then decreased with increasing starch content. This behavior was related to the dependence of softening or reinforcing effect on the level of starch concentration in the samples. Adherence load and energy decreased with the addition of pregelatinized starch implying the decrease in adhesiveness of the samples. Furthermore, increasing the pregelatized starch amount also increased the liquid sealing duration of the samples at both 23 and 37 °C. Cytotoxicity tests against osteoblasts using a MTT assay revealed that the all the prepared samples and their raw materials did not show any cytotoxic potential. Formulations containing pregelatinized starch content between 20 and 30 % were found to show optimized performance.

In this study, preparation and characterization of antibiotic-impregnated microporous nano-hydroxyapatite (HA) aiming to function as both antibiotic carrier and bone graft for osteomyelitis treatment were carried out. Microporous nano-hydroxyapatite was prepared by low temperature phosphorization of three-dimensional printed calcium sulfate sample and was impregnated by three types of antibiotics including vancomycin, fosfomycin and gentamicin. Materials properties and antibacterial performance including phase composition, microstructure, degradability, total drug loading, antibacterial activity and shelf life were investigated and reported. Microporous nano-hydroxyapatite having porosity and mean pore size of 63.92% and 0.15 microns was prepared and showed greater resorbability than typical high-temperature sintering samples. Sustained release of antibiotic from the impregnated samples for longer than 29 days was observed, but the difference in the efficiency was related to the difference in the molecular weight, mechanism of action, spectrum of activity of each antibiotic. No deterioration in the antibacterial activity of the prepared antibiotic-impregnated hydroxyapatite was observed after storing for up to 12 months. No cytotoxic potential by MTT assay at all extraction periods was observed for vancomycin-impregnated hydroxyapatite. Gentamicin and fosfomycin impregnated hydroxyapatites showed cytotoxic potential only on day 1 extraction, but no cytotoxic potential was observed on day 2 extraction onward. This could be related to the concentration and characteristics of each released antibiotics.

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Background Hydroxyapatite is widely used as a coating on metallic implants to promote bioactivity. The coating is typically produced using a high temperature, resulting in phase heterogeneity and coating delamination, which may lead to failure of the coating clinically. Development of a simple and low-temperature hydroxyapatite coating technique may improve the bone bonding ability of implants. Objectives To investigate responses to hydroxyapatite-coated titanium produced by a newly developed sol–gel by osteoblasts in vitro and bone in vivo. Methods Osteoblast proliferation was characterized using a methyl thiazolyl tetrazolium assay and cell calcification with an Alizarin red S assay, and the results were compared with those of uncoated titanium. Uncoated and coated screws were inserted into the trabecular bone of New Zealand white rabbit legs. These implants were evaluated mechanically and histologically after 7, 12, and 24 weeks. Results Hydroxyapatite-coated titanium showed a significantly greater cell proliferation and mineralization than uncoated titanium. Extraction torques for the coated screws increased with time of implantation and were significantly greater than those of uncoated screws. We observed bone fragments attached to the surface of all coated screws after removal, but none on uncoated screws. Hematoxylin and eosin-stained bone showed no active inflammatory responses to implantation at any time examined. Bone surrounding either uncoated or coated screws followed typical remodeling stages, but maturation of bone healing was faster with coated screws. Conclusions The sol–gel-derived hydroxyapatite coating showed bioactivity, indicating its potential application as an alternative coating technique to improve the bone bonding ability of implants.