PhD Thesis Presentation - Multifunctional Biomaterials Based on Graphene and Smart Hydrogel

Graphene is an emerging two-dimensional carbon material, and its applications in biomedical fields such as biosensing, tumor diagnosis, drugs and gene carriers, antibacterial and tissue engineering, etc. have attracted more attentions. In this thesis, we combine 3D graphene with functional hydrogel and other biomolecules for epidermal strain sensor, peripheral nerve regeneration and tumor therapy. We utilize the good conductivity and layer by layer structure of graphene foam for resistance type strain sensor. The double network hydrogel as substrate provides good protection of GF structure and large elongation for wide sensing range. Besides, modified chitosan adhesives onto hydrogel achieve conformal adhesion of sensor. The good combination is also applied as nerve regeneration conduit that the good conductivity of graphene promote adhesion, proliferation and differentiation of Schwann cell and keep on electrical conduction between damaged nerve ends as bridge. Meanwhile, hydrogels mimic the characteristics of native extracellular matrix (ECM) and benefit the cellular growth and tissue formation. GelMA hydrogels with matrix metalloproteinase and arginine-glycine-aspartic acid peptide motifs promote proliferation of cells. Later, the nerve growth factor (Netrin-1) with gradient concentration in conduit is introduced as biological cue to guide the cells and promote the regeneration. And dry double sided adhesive tape based on natural silk/Ca2+ are fabricated to replace commercial tissue glue (Octyl Cyanoacrylate) for non-suture surgery. In the end, graphene nanospheres with MnO2 and Fe3O4 nanodots contained fatty acid, DOX (drug) and TPP (photosensitizer) are designed for all in one tumor therapy (photothermal/photodynamic/chemo therapy). Fe3O4 nanodots are designed for magnetic target. Under the NIR irradiation, the temperature increases to kill tumor cells and melt fatty acid to release DOX and TPP. MnO2 can decompose H2O2 to H2O and generate O2 in tumor cell which further become singlet oxygen when catalyzed by TPP and cause apoptosis of cell.