The in vivo thrombosis evaluation for the biodegradable polymer stent / 生物医学工程学杂志

New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation on similar instruments and show the methodology on the preclinical evaluation.

Biosafety evaluation strategy and practice of tissue induced biomaterials / 中国组织工程研究

BACKGROUND: Due to the complexity of tissue induced biomaterials, the current biosafety evaluation standard is not available. For years, to choose an effective evaluation strategy and practice in tissue induced materials has been always a hot topic, but still with no conclusion. The existence of this problem results in numerous issues for manufactures when conducting the biosafety evaluation of tissue induced medical devices. OBJECTIVE: To formulate the biosafety evaluation strategy that should be followed by the material samples at the research and development stage and to provides some ideas and lessons for the selection of the product biology experimental items to be listed and registered. METHODS: In 2016, a statistical analysis was carried out for biological test items of tissue induced biomaterials. Cytotoxicity, irritation and sensitization tests were the most commonly used tests for biomaterials and medical devices. A biosafety evaluation only via the above three tests had been applied in 58 kinds of materials with 81 batches of samples. In this study, immune toxicity tests were performed in 17 kinds of materials and biodegradation tests were done in some samples. RESULTS AND CONCLUSION: It had been found that different test programs or evaluation strategies may be adopted in the product development or listing registration stage. At early stage of development, cytotoxicity, irritation and sensitization tests are suitable for sample screening. In the later stage of research and development, more in-depth tests, such as subchronic toxicity, degradation and immunity toxicity, should be employed to meet the safety evaluation requirements.

Biocompatibility analysis of hyaluronic acid sodium gels for medical application / 生物医学工程学杂志

Hyaluronan acid sodium gels are used in ophthalmic surgery, orthopedic treatment and cosmetic surgery. In 2009,there were 12 domestic manufacturers in China producing 33 kinds of products. 23 kinds of imported products were allowed by SFDA to sale in the meantime. Since manufacturers use different production processes, product performances are quite different. According to the GB/T 16886. 1-2001, we designed a pilot program to evaluate the sodium hyaluronate gel products comprehensively in this paper. The results showed that, except chromosome aberration test of gel A and subchronic systemic toxicity of gel C appeared positive, the remaining samples of the test results were negative. This article provides a reference to write standard of cross-linked hyaluronic sodium gel and the revision of standard YY0308-2004.

A comparative study of PTT and CT tests for coagulation evaluation of cardiovascular system external communicating devices / 生物医学工程学杂志

Based on GB/T16886.4-2003 Standard, the coagulation effects of 5 cardiovascular system external communicating devices made consist of metal and polymer were assessed using the partial thromboplastin time (PTT) and Lee-White coagulation time (CT) tests. The results indicate that PTT test is a stable and valuble method for evaluating the coagulating pathway disturbance of the devices. In line with GB/T 16886.4-2003 Standard, PTT test is a recommendable method for evaluating the external communicating devices Based on GB/T14233.2-2005 Standard, CT test is a method more liable to variation, compared with PTT test. This is due to the complex relativity in the test itself, due to all the factors of coagulating cascade, and due to the individual difference of animal. The question of how to select proper negative control for coagulation evaluation of the Cardiovascular System External Communicating Devices in clinical setting for CT test should be addressed and studied.

A comparative study on dual-magnetic circuit beads and scattering nephelometry coagulometers in coagulational evaluation of blood-contact medical devices / 中国医疗器械杂志

Dual-magnetic circuit beads and scattering nephelometry dual channel semiautomatic coagulometers are used for the coagulational evaluation of the 5 blood contact medical devices which consist of metals and polymers. The partial thromboplastin time(PTT) and prothrombin time(PT) tests are made based on the GB/T 16886.4-2003 standard. The results indicate that the coefficient of variation in the two groups is in the identical order of magnitude. In the PTT tests, they give the similar evaluational results. With the smaller numerical values of the PT tests, the different coagulometers give the high consilience results. So, both of dual-magnetic circuit beads and scattering nephelometry coagulometers are acceptable in the medical devices' coagulational evaluations. But the interpretation and analysis of the results of the small numerical value tests, PT tests for example, should be noticed.