Biocompatibility of an implantable thermosensitive hydrogel in vitro / 中国组织工程研究

ABSTRACT

BACKGROUND: Thermosensitive hydrogel has made great progresses in drug carrier and tissue engineering. However, its phase-transition temperature is lower than human body temperature, so it has not been used as implants. OBJECTIVE: To prepare and evaluate the biocompatibility of a thermosensitive hydrogel poly-(N-isopropylacrylamide-co-N-hydroxymethylacrylamide)[P(NIPAAm-co-NHMPA)] In vitro so as to assess its safety as a medical implant.DESIGN, TIME AND SETTING: Material experiment was performed at the Central Laboratory of Union Hospital of Tongji Medical College, Huazhong University of Science & Technology and Key Laboratory of Biomedical Polymers, Ministry of Education, Wuhan University Chemical Department from January to October 2007.MATERIALS L929 mice fibroblast line was provided by Professor Chen, Stomatology Hospital of Wuhan University. N-isopropylacrylamide and N-hydroxymethylacrylamide were purchased from Aldrich.METHODS: Using ammonium persulfate and tetramethylethylenediamine as oxidateion-reduction initiation system and N, N'-methylene bisacrylamide as crosslinking agent, mass fraction 8.5% N-hydroxymethylacrylamide was added to the reaction system. The N-isopropylacrylamide and N-hydroxymethylacrylamide were dissolved in deionized water and reacted with N, N'-methylene bisacrylamide, ammonium persulfate and tetramethylethylenediamine at room temperature for 3 hours. The colorless transparent cylinder gel was obtained, soaked in deionized water and dried.MAIN OUTCOME MEASURES: Biocompatibility in vitro of the material was validated by cytotoxicity test, cells/scaffolds interaction test, hemolysis test and pyrogen test in vitro.RESULTS: Synthesized hydrogel showed thermosensitive character as expected and the lower critical solution temperature was 38 ℃. The toxicity rate was grade 0-1. Through the scanning electron microscopy, cells and scaffolds were tightly attached, producing a perfect interface, and the shape of cells was all right. Hemolysis rate was 2.54%. No pyrogen reaction was found. CONCLUSION: P(NIPAAm-co-NHMPA) has been successfully prepared with good biocompatibility in vitro and might become a good medical implant for clinical use.