To evaluate the effect of deacetylation degree (DDA) on the gelation behavior of thermosensitive chitosan-β glycerol phosphate disodium salt pentahydrate (CH-GP) system and to compare their rheological behaviors before and after gelation. Methods A series of thermosensitive CH-GP samples with different DDAs (70%, 85%, 90%, 97%)were prepared by dissolving CH with 0.1 mol/L HCl solution, 5 samples for every single DDA, and then all these CH-GP solution samples processed the frequency sweep test and temperature sweep test (10-70℃ , 1℃ /min) on AR 2000ex rheometer, with pH value of 7.02. Also, all the results of hydrogel samples were processed a frequency sweep test. Results With CH concentration of 2% (w/v) and pH value of 7.02 , the gelating temperature of CH-GP systems with different DDAs (85%, 90%, 97%) were (59.90 ± 0.08), (48.10 ± 0.08), (37.10 ± 0.11) ℃ , respectively. While the gelating temperature of CH-GP system with 70% DDA was over 70℃ . There were statistically significant differences in temperature and time of gelation among groups with different DDAs (P lt; 0.05). Furthermore, storage modulus of such system raised from dozens Pa to a magnitude of several kPa during gelation , while loss modulus kept almost steady. Conclusion Gelating temperature and mechanical property of the system could be measured objectively by rheological characterization. Thus during designing tissue engineered scaffolds for various purposes, it is helpful applying selected CH with optimal DDA to different target tissues.
Thermosensitive hydrogels are smart materials that undergo sol-gel phase transitions in response to body temperature, exhibiting excellent injectability and biocompatibility. This review systematically summarizes the research progress on their applications in the gastrointestinal tract, mainly focusing on drug delivery and endoscopic submucosal dissection (ESD) assistance. In terms of drug delivery, compared with conventional carriers such as nanoparticles and liposomes, thermosensitive hydrogels offer prolonged mucosal retention time, better stability, and more controllable drug release properties, and can be administered orally or locally for treating oral ulcers, gastric ulcers, inflammatory bowel disease, and gastrointestinal tumors. In ESD procedures, thermosensitive hydrogels serve as submucosal cushions to effectively elevate lesions and prevent thermal injury, while also facilitating postoperative wound closure, hemostasis, and healing promotion. This review also discusses optimization strategies and challenges in clinical translation for thermosensitive hydrogels, and provides perspectives on future development trends, aiming to provide references for their further application in gastrointestinal disease treatment.
Methylcellulose is a semi-flexible cellulose ether derivative, whose hydrogels are thermosensitive and reversible, with good biocompatibility and adjustable function, and its application has attracted much attention in the biomedical field. In this paper, the application of methylcellulose-based thermo-sensitive hydrogels in biomedical field was reviewed. Based on the mechanism of gelation and influencing factors of methylcellulose, this paper focused on the recent advances in biomedical applications of methylcellulose-based hydrogels, including drug delivery, regenerative medicine, and other related fields. The current achievements in these fields were summarized in the form of lists in this paper to provide ideas and tendencies for future research. Finally, the future development of multifunctional methylcellulose-based hydrogel materials with improved performance was also discussed.
