The Application Research Of Supercritical Fluid Preparation Of Artificial Bone Tissue

Orthopedic clinical surgery mainly uses autologous bone, allograft or xenograft bone to defected repair, and xenograft bone has a wide range of sources. In the process of bone grafts, lipid and protein in bone are often sterilized by extraction and oxidation in orthopedic surgery to promote bone conduction for the safety of bone grafts. In this paper, we use supercritical CO2as solvent on xenogeneic cancellous bone extraction and use single-factor experimental to determine the optimum extraction process parameters:pressure25MPa, temperature45℃, sheet sample particle size3mm×3mm×3mm, extraction process using95%(v/v) ethanol as entrainment agents, holding pressure and temperature for1h, looping extraction for2h.In this paper, by making comparison with the traditional extraction methods, thermal gravimetric analysis showed that the sample defatted by supercritical fluid extraction method was16.00%weight loss, the sample defatted by methanol/chloroform was35.11%weight loss, so supercritical fluid extraction method was proved more effective than traditional degreasing solvent extraction. While using infrared spectroscopy to verify the conclusions of thermal gravimetric analysis, it confirmed that the sample dealt with supercritical extraction method was no residue, and the original hydroxyapatite xenograft bone structure was not destroyed. And through environmental scanning electron microscopy and mechanical properties test, it showed the supercritical CO2extraction of lipids from xenograft bone was better and did not affect the mechanical properties of xenograft bone.In terms of protein removal, the paper used H2O2as a solvent to degrease ultrasonic bone conducted after removal of protein processing, and the first use of high-temperature supercritical method in addition to heterologous protein in bone. Detected by Kjeldahl, environmental scanning electron microscopy and other test methods, it showed that H2O2solvent ultrasonic method can effectively remove the protein, but the mechanical properties were reduced after treatment. The supercritical fluid extraction method for the removal of proteins was not very effective, but it can maintain the mechanical properties of the bone, and have good mechanical properties of bone tissue materials, so it was still needed to be studied.Subsequently, according to the experimental design process, the supercritical CO2extraction process was amplified and conducted the economic analysis. Although the supercritical CO2extraction equipment got a larger one-time investment, but it can effectively reduce energy consumption, and produce safety. It can also contribute to environmental protection, adaptation and sustainable development. Although the traditional methods of treating xenograft bone had the low equipment investment and operating cost, but considering the requirements and safety of clinical bone tissue material, the use of supercritical methods for treating xenograft cancellous bone was still irreplaceable.