| Objective:Preparing zinc oxide/chitosan/β-glycerophosphate thermal-sensitive hydrogel by the physical cross-linking and evaluating its physicochemical properties,antibacterial ability and cytocompatibility,and validated its potential as a hydrogel for clinical applications in treating peri-implant inflammation.Methods:1.ZnO-NPs was characterized by Scanning electron microscopy（SEM）and Transimission electronic microscopy（TEM）.With different weight ratio between ZnO-NPs and CS,1%,3%,and 5%of ZnO-NPs/CS/β-GP hydrogels were prepared.Using the test tube inversion method,SEM,Fourier-transform infrared spectroscopy,the influence of ZnO-NPs on gelation time,chemical composition,and cross-sectional microstructures were evaluated.2.The antibacterial capacity of hydrogels against Porphyromonas gingivalis（P.gingivalis）was detected by bacteriostatic zone and colony counting.The hydrogel’s bacteriostatic mechanism was investigated using live/dead fluorescent staining and scanning electron microscopy.Crystal violet staining and MTT assay were used to further observe the effects of hydrogel on P.gingivalis biofilms.CCK-8 method was used to detect the cytotoxicity of the hydrogels,and living/dead cell staining was adopted to observe the spreading morphology of gingival fibroblasts（L929）cultured with the extracts of the hydrogels.Results:1.ZnO-NPs were found to be irregular shape with the size of 20-30nm by TEM.The ZnO-NPs/CS/β-GP hydrogels have injectable sensitivity and all become hydrogels at 37°C.The hydrogel-forming time was shorter when ZnO-NPs content was higher,and the gelation time of 5%ZnO-NPs/CS/β-GP decreased to（1.19±0.14）min.The p H of hydrogel is between 6.8～7.3,which is in line with human physiological range.All the hydrogels exhibited a homogeneous interconnected porous structure.The addition of ZnO-NPs does not affect their microstructures,and micro-nano particles are evenly embedded in the hydrogel’s pore wall.Compared with CS/β-GP,the infrared spectra of composite hydrogels did not produce a significant new absorption peak,but expansion joint at 3421 cm-1strengthened and shifted to a low wavenumber,indicating that the intermolecular hydrogen bonding force of composite hydrogels was enhanced.2.The hydrogel could inhibit the growth of P.gingivalis in all groups,and the antibacterial rate increased with the increase of ZnO-NPs content（P<0.05）.The bacterial rate of 3%and5%ZnO/CS/β-GP were both close to 100%.The diameters of antibacterial ring of 1%,3%and 5%ZnO-NPs/CS/β-GP groups were 16.4,14.9 and 11.7mm,respectively,which were significantly larger than those of CS/β-GP group（8.9mm）（P<0.05）.SEM results showed that CS/β-GP treated bacteria damaged part of cell membrane edge,and ZnO-NPs/CS/β-GP treated bacteria had obvious collapse and rough serrated edges,which damage significantly than CS/β-GP.In addition,3%and 5%ZnO-NPs/CS/β-GP exhibited good antibacterial activity in inhibiting the formation of biofilms and eradicating existing biofilms,and the difference was significant compared with CS/β-GP group（P<0.01）.The cell viability of gingival fibroblasts（L929）co-cultured with hydrogel in each group was above 90%after 24,48,and 72 h,and the hydrogels of each group revealed no apparent cytotoxicity toward L929cells.Under inverted fluorescence microscope,cells of all experimental groups had clear contour,fusiform,and good spread shape.In addition,the cells were basically green fluorescence,which had good biocompatibility.Conclusion:The ZnO-NPs/CS/β-GP composite hydrogel prepared in this study has antibacterial properties,can inhibit the formation of P.gingivalis biofilm,and has good biocompatibility.In addition,it has stable physical and chemical properties,which could be injected into the periodontal pocket in solution form and quickly transformed into hydrogel,simple and convenient operation.In conclusion,ZnO-NPs/CS/β-GP thermosensitive hydrogels could be expected to be utilized as adjuvant drugs for clinical prevention and treatment of peri-implant inflammation. |
PDF Full Text Request