Objective Chitosan has been widely studied in the fields of biomedical materials and tissue engineering,due to its good water solubility,biocompatibility,biodegradability,film-forming property,hemostasis,wound healing and anti-inflammatory effects.Flies maggot shell contains much chitosan,which is one of the excellent raw materials.The aim of this study is to provide integral biological assessment on chitosan trauma dressing.Methods Chitosan samples were subjected to physicochemical analysis (relative molecular mass,degree of deacetylation,and content of heavy metal),bacteriostatic test,skin sensitization,cytotoxicity tests as well as hemolysis test according to national standard of China.Results The relative molecular mass of chitosan was 266 ku,the degree of deacetylation of chitosan was 75％,and the content of heavy metal was less than 10-5.The cytotoxicity level was evalnated at the first level which indicating the low cell toxicity.Skin sensitization test showed that no sensitization reaction was practically detected.The hemolysis rate was 0.769％,which was less than 5％,indicating zero hemolysis.Conclusions Chitosan has good character,which may meet the requirements of biological and medical application.

Bone-guided hearing aids are an important means of compensating for hearing loss. In recent years, with the advancement and iteration of new technologies and functions, the development of bone-guided hearing aids has been progressing rapidly, resulting in the constant emergence of various new products. However, the current lack of corresponding evaluation standards for this product has led to difficulties in registration, marketing, quality control, and evaluation standards. This study focuses on the technical evaluation perspective and elaborates on the main points of focus in technical evaluation work, such as product structure composition, main risks, performance requirements, and clinical evaluation. The aim is to provide a basis for the design and development, production, registration, use, and post-market supervision of the product.

With the development of the medical cosmetology industry, the market demand for medical sodium hyaluronate dressing is gradually increasing, but at present the product lacks the corresponding national standards. This problem makes this type of product face the problem of non-uniform standards in the quality control, registration declaration information content, technical review requirements, and other aspects. In this review paper, the classification of medical sodium hyaluronate wound dressing products was introduced, and the key points of the technical review were discussed, involving the division of the registration unit, raw material control, product performance indicators, and clinical evaluation. In addition, the key information review requirements in the process of registration and declaration of such products were analyzed, with a view to providing technical references for manufacturers and relevant regulatory agencies.