The Preparation And Characterization Of GO Hybrid Supramolecular Composite Hydrogels

An ideal biomaterial scaffold,hydrogel,can stimulate the growing environment in our body for cells.At the same time,the released drug or bioactive molecule from hydrogels can be used for tissue engineering repair and regeneration.However,most polymeric materials or hydrogels are likely to generate cracks when subjecting to mechanical damage,and the functions of materials will be severely affected with the crack propagation,which greatly limits their applications in tissue engineering.Therefore,the development of biocompatible hydrogels with self-healing properties are highly needed.Meanwhile,these hydrogels with injectable ability can be used as drug or cell devices for tissue engineering,and the released drugs or cells can directly repair the damaged tissue without transporation.In this article,based on graphene oxide(GO),a tunable bio-adhesive and self-healable GO hybrid supramolecular hydrogel and a GO composite hydrogel with injectable ability were developed,respectively.And then the drug release behavior from our GO-HSH hydrogel was investigated and cells were encapsulated into the GO composite hydrogel.The UPyMA monomer was synthesized by the reaction of 6-methylisocytosine and 2-isocyanatoethyl methacrylate.Then N-isopropylacrylamide(NIPAM)and UPyMA monomers were added to GO dispersion,and the GO hybrid supramolecular hydrogels(GO-HSH)with self-healable and tunable bio-adhesive properties,were prepared by one-pot free radical polymerization.To demonstrate the self-healing ability and bio-adhesive property of GO-HSH hydrogel,the rheological and a leap shear measurement was performed,and the maximum adhesive force of the GO-HSH hydrogel is about 0.69 N at 25 ~oC,however,the value increases to 1.3 N at 37 ~oC.The results of SEM demonstrate that GO-HSH hydrogel adjust its internal microstructure upon the external temperature change.In addition,the pH responsive release behavior of DOX from GO-HSH hydrogel illustrates that it is a usefull drug delivery for chemotherapies.There was approximately 22%of DOX released at pH 7.4 during the first 24h,however,it was found amount of DOX(54%)was released from the GO-HSH hydrogel at pH 5.5 after 24 h.Also,the released DOX from the hydrogel remains bioactivity and has high capability to kill tumor cells.The injectable GO composite hydrogels were prepared by mixing the aqueous GO dispersion with thermo-sensitive nanogel dispersion.Fourier-transform infrared(FT-IR),Atomic Force Microscope(AFM)and Ultraviolet Spectrophotometer(UV)were performed on tNG/GO composite hydrogels,revealing that reversible hydrogen bonds between tNG and GO nanosheets.In addition,significantly high antibacterial activities were found among tNG/GO hybrid dispersions.After 10 h incubation,the antibacterial activities of tNG/GO hybrid dispersions are 97.2±3.9%for E.coli and 100%for S.aureus,respectively.Also,the release behavior of FITC-dextran from the hybrid hyrogels could also be tuned by dynamic temperature control.Moreover,the hybrid hydrogels might be used as interesting cell carriers due to their outstanding cytocompatibility,and the encapsulated BMSCs cells remain high cell viability(95%)after incubated 3 days.