Study On Preparation And Properties Of Graphene-based Composite Hydrogels

In the past half decade, graphene has attracted a great deal of attention due to its unique structure and outstanding chemical and physical properties. Graphene-based composites in biological sensing, biological separation, tissue engineering areas and drug controlled release show wide application prospects. Graphene-based hydrogels are becoming the focus of biomedical research because its high water content, larger specific surface area, biocompatibility and high drug loading rate, etc. In this thesis, multifunctional hydrogels were prepared on the basis of graphene oxide by in situ gel method and electrostatic self-assembly. Three kinds of novel graphene-based composite hydrogel have been prepared by "green" method. Firstly, the reduced graphene oxide (rGO)/Brassica chinensis extract (Bce) hydrogel was prepared and applied in anti-tumor; Then (rGO)/Amaranth extract(ARE)/Gold (Au) composite hydrogel was designed to combine photodynamic therapy and photo-thermal therapy; Lastly graphene oxide/chitosan-hydroxyapatite hydrogel films were constructed by layer-by-layer self-assembly. The ability of drug load and release in the hydrogel films was investaged. The researches are similar to above have not been reported.The main contents of the thesis are as below:1. The rGO/Bce hydrogel was fabricated by using biomolecules in brassica chinensis extract as reducing agents, photosensitizer and cross-linking agents. The interactions, such as amide bond and hydrogen bond existed between amino-group and carboxy group etc. of Bce and GO, which benefited for the formation of composite hydrogel. The chlorophyll and chloroplastin in the hydrogel were used as PDT drugs when irradiation with650nm laser. Furthermore, the chlorophyll and chloroplastin were encapsulated tightly in the GO-based hydrogel matrix, through strong multiple interactions which can keep efficiently desirable drug concentration and targeted for effective PDT treatment. This hydrogel can also carry other drugs, such as chemotherapy drugs, etc. The system has a medicine significance and potential application in the field of tumor treatment. 2. RGO/ARE/Au composite hydrogel was prepared by using amaranth extract as reducing agents, photosensitizer and cross-linking agents. Gold chloride acid was reduced into gold nanoparticles and encapsulated in the hydrogel. The interactions, such as amide bond and hydrogen bond existed between amino-group and carboxy group etc. of ARE and GO, which benefited for the formation of composite hydrogel. The chlorophyll and chloroplastin in the hydrogel were employed as PDT drugs when irradiation with650nm laser. Simultaneously, Au nanoparticles in the hydrogel has photo-thermal effect when irradiation with laser, this will promote cancer cell death. The multifunctional hydrogel prepared provides a new idea for multiple antitumor.3. GO is like an amphiphilic macromolecule with hydrophilic edges and a more hydrophobic basal plane, which make it water dispersible and provide sites for various supramolecular architectures. The CTS/GO composite hydrogel film was assemblied by using layer-by-layer technique. Based on this template, the hydroxyapatite nucleated and grew in situ by means of biomimetic synthsis. On account of good biocompatibility of CTS/GO/HA, the hydrogel films may have significant application in the biological scaffold material of bone tissue engineering. The controlled-release of acetylsalicylic acid in CTS/GO/HA hydrogel film demonstrates its anti-inflammatory function and good medicine prospects which is worthy of our in-depth exploration.