[Research on Characterization and Biocompatibility of 3D Printed Ti-6Al-4V Pelvic Prosthesis].

The treatment of bone defects caused by fractures or bone tissue lesions has always been a difficult problem in the field of orthopedics. Implantation of high-performance titanium alloy prosthesis is an effective method to treat bone defects. 3D printing technology can produce low-modulus titanium alloy implants with porous structures, providing a better solution to the above problems. This technology is convenient to design and has a huge advantage in making orthopedic implants. The article used electron beam melting in 3D printing technology to create two samples of Ti-6Al-4V prosthesis, including solid structural pelvic prosthesis and porous structural pelvic prosthesis. The mechanical properties of the prosthesis showed that the yield and tensile strengths of the rod tensile specimen were 894 MPa and 956 MPa, respectively, and the compressive modulus and compressive strength of the porous pelvic prosthesis were 55 GPa and 65.2 MPa, respectively. The results of the L929 cytotoxicity assay and the MC3T3-E1 cell adhesion assay demonstrated good biocompatibility of the prosthetic samples. New Zealand white rabbits were used to prepare the femoral joint cavity defect models and two pelvic prostheses were implanted. A microscopic CT scan 4 weeks after implantation showed that the bone defect caused by the drill had healed and that the porous structure of the pelvic prosthesis formed a new trabecular structure within the hole. In conclusion, the 3D printed Ti-6Al-4V pelvic prosthesis has excellent mechanical properties, biocompatibility, and the ability to promote new bone growth.

[Study on Analytical Method of Leachable Substances of Allogeneic Products].

Products made from allogeneic tissue are largely used in clinical treatment due to its wide source compared with autologous tissue, causing less secondary trauma of patients and the good biocompatibility. Various organic solvents and other substances introduced in the production process of allogeneic products will leach down into the human through clinical treatment, thus bringing varying degrees of harm to patients. Therefore, it is very necessary to detect and control the leachables in such products. Based on the classification and summary of leachable substances existing in the allogeneic products, the preparation of extract and the establishment of the detection techniques for known and unknown leachable are briefly introduced in this study, in order to provide research method for the study of leachable substances of allogeneic products.

[Review of Leachable Substances in Hemodialyzer].

With the rapid development of my country's hemodialysis industry, the application of hemodialysis machines has become more and more extensive, but at the same time, the quality control technology of hemodialysis machines is not perfect. Especially for a wide range of leachable substances in dialyzers, there are few studies and detection methods. This study first briefly describes the development of hemodialyzers, and then expounds the common types of leachables, extraction methods, and chromatography and mass spectrometry conditions. It is summarized that the research plan of leachable substances is to determine the type first, then formulate the extraction plan, and then establish the detection method. Finally, we look forward to the research prospects of hemodialyzer leachables, and point out that with the deepening and extensive development of research, it can further promote the healthy development of the hemodialyzer industry.

Biodegradable 3D printed HA/CMCS/PDA scaffold for repairing lacunar bone defect.

Three-dimensional (3D) printing technology has attracted considerable focus for preparing porous bone repair scaffolds to promote bone regeneration. Inspired by organic-inorganic components and the porous structure of natural bone, novel porous degradable scaffolds have been printed using hydroxyapatite (HA), carboxymethyl chitosan (CMCS), and polydopamine (PDA). The well-designed HA/CMCS/PDA scaffolds exhibited a porous structure with 60.5 ± 4.6% porosity and 415 ± 87 µm in mode pore diameter. The weight loss percentage (WL%) of the HA/CMCS/PDA scaffolds reached about 17% during a 10-week degradation in vitro. The degradation process between the CMCS and HA induced the release of calcium ions. Using commercial product as the contrast material, the osteogenic properties of the scaffolds were assessed in vivo. The implantation and degradation of HA/CMCS/PDA scaffolds had no adverse effects on the kidney and liver of rabbits with no inflammatory response in the implantation sites. The micro-CT and histology data suggested that the HA/CMCS/PDA scaffolds could effectively stimulate new bone formation within the femoral lacuna defect region of rabbits versus blank control at 12 weeks after implantation. Surface cortical bone was generated in the defect area in the HA/CMCS/PDA group; the defect in the blank group remained obvious. HA/CMCS/PDA scaffolds had excellent biodegradability matching the formation of new bone during implantation. In conclusion, 3D-printed HA/CMCS/PDA scaffolds have remarkable potential as a new material for repairing bone defects.