Glutaraldehyde (GA) is an important additive that is mainly used in animal-derived biomaterials to improve their mechanical and antimicrobial capacities. However, GA chemical toxicity and the metabolic mechanism remain relatively unknown. Therefore, residual GA has always been a major health risk consideration for animal-derived medical devices. In this study, extracts of three bio-patches were tested via the GA determination test and mouse lymphoma assay (MLA). The results showed that dissolved GA was a potential mutagen, which could induce significant cytotoxic and mutagenic effects in mouse lymphoma cells. These toxic reactions were relieved by the S9 metabolic activation (MA) system. Furthermore, we confirmed that GA concentration decreased and glutaric acid was generated during the catalytic process. We revealed GA could be oxidized via cytochrome P450 which was the main metabolic factor of S9. We found that even though GA was possibly responsible for positive reactions of animal-derived biomaterials’ biocompatibility evaluation, it may not represent the real situation occurring in human bodies, owing to the presence of various detoxification mechanisms including the S9 system. Overall, in order to achieve a general balance between risk management and practical application, rational decisions based on comprehensive analyses must be considered.
In this study, nanofiber cellulose (NFC) based on a 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidization method was successfully combined with chain-end-functionalized polyethylene containing alkoxysilane via silanization. Fourier transform infrared spectroscopy, transmission electron microscopy, contact angle measurements, Molau tests, and X-ray photoelectron spectroscopy analyses provided further evidence for the effectiveness of the surface modifications. The hydrophilic surface characteristics of NFC were changed to apparently hydrophobic for the modified nanofiber cellulose (M-NFC). Then, the linear low-density polyethylene (LLDPE)/M-NFC nanocomposite was prepared, and the mechanical properties, thermal properties, and crystallization properties of the LLDPE-M-NFC were investigated by tensile testing, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The results show that after modification, the thermal stability of NFC was enhanced. The interface between M-NFC and the matrix was good. The tensile strength and Young's modulus values of the nanocomposites were enhanced compared with those of LLDPE; in particular, the tensile strength and Young's modulus of the blend with 5 wt % M-NFC increased by 56 and 106%, respectively. The storage modulus of the nanocomposites was enhanced obviously over a wide temperature range. The addition of a small amount of M-NFC had slight effects on the crystallinity and melting temperature of LLDPE. V C 2017 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2017, 134, 45387.
Tissue engineered medical products (TEMPs) use state-of-the-art technologies and offer the patients with alternative clinical options for diseases that conventional treatments may fail or be incompetent. However promising, this technology is comparatively new with very limited hands-on experiences with both manufacturing and clinical therapy. Of great significance to products with such complexity and novelty is the establishment of a complete jurisdiction framework and a standardization database so that the safety of the technique in clinical treatment can be ensured. Although different regulatory routes are adopted in different countries, risks are generally considered to be derived from the cellular components within the product, the material scaffolds, and potentially from the final products. This article is to provide an insight of the regulatory considerations and the role of China Food and Drug Administration (CFDA) in the supervision of TEMPs.
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