Preparation and Applications of Functionalized Biointerface Based on Honeycomb Structure
Author:Chen Shuang Shuang
Supervisor:lu qing hua
Cells take cues from the surfaces they encounter in their physiological environment.The cells recognize the mechanical,chemical,spatial,and even temporal information from the surface,but which features they read and how they integrate and translate them into specific behavioural responses is still almost a black box.The requirements for investigation in the interaction between cells and biointerface derived tremendous interesting research topic.Among them,the fabrication of biomimetic surface has attracted great attentions.The honeycomb surface with characters as the highly ordered hexagonal pore array exhibited high mechanical stability,porosity and the capability to exchange the nutrients and metabolic waster products.The honeycomb cell scaffold which should be potentially applied biomedical filed encountered hindrance from its intrinsic monotony.It is a challenge to fabricate the honeycomb surface with rationally designed properties.In this dissertation,we functionlized the honeycomb films into different biointerfaces with controllable adhesion.The details are as follows:(1)Hierarchical cell scaffolds with defined multiple scale structures are considering as the future generation of cell culture substrate which provides the most approximate state to the natural extracellular physiological environment.In this study,the polyphosphazene nanoscale structures were in-situ grown from the honeycomb films.The parameters including density,diameter,and distribution of nanometer scale polyphosphazene particles can be delicately regulated.The hierarchically structured materials were biocompatible and maintained excellent cellular adhesion and spreading.Hence,the newly developed materials would be promising for the application of cell scaffold.(2)Inspired by the typically adhesive behaviors of fish skin and Parthenocissus tricuspidata,two different decorations of zwitterionic polymer(polySBMA)on polystyrene honeycomb membrane were carried out to explore controllable bio-adhesive surfaces.Casting and dip-coating were employed to graft polySBMA onto the plasma treated PSHCM.Interestingly,the polySBMA casted PSHCM showed a uniform covering layer on the PSHCM just like the mucus layer on fish skin,presenting excellent anti-fouling property.On the contrary,dip-coated one showed the polySBMA aggregating on the honeycomb pore walls forming a large number of sucking disks like adhesive disks on the tendrils of P.tricuspidata,which remarkably boost cell adhesion on substrates.Thus,bio-adhesion could be regulated as desired by tuning the distribution of zwitterionic polymer on the honeycomb surface.(3)A novel approach for the fabrication of penetrative honeycomb film was fabricated via plasma treatment and was modified with thermoresponsive polymer(poly(N-isopropylacrylamide),pNIPAAm).In detail,the thermoresponsive polymer was grafted through the penetrative honeycomb film via a reversible addition-fragmentation chain transfer(RAFT)method.It can be demonstrated by AFM in this work that the highly ordered hexagonal pore structure was kept however the morphology of pNIPAAm was thermoresponsive: aggregating inside the honeycomb holes in lower temperature and swelling out of holes in higher temperature.The films were found to support the cell culture and enhance cell adhesion and stimulate cell growth when compared with flat one.Furthermore,cells can be harvested with decreasing temperature below the LCST.The resulting membrane exhibits promising application in the cell sheet engineering.(4)Aiming to understand cell responding towards concave-convex structure at subcellular level,colloidal-crystal-arrayed and honeycomb-structured surfaces with highly ordered hexagonal structure and totally inverse curvature were fabricated via facile self-assembly and breath figures,respectively.The differential regulation of both hexagonal curvatures in cells fate was investigated in this work.The cells exhibited more spreading on the convex colloidal-crystal-structured surface,while showed more intensive adhesive force on the concave honeycomb surface.The cellular behaviors on the different structured surfaces were portrayed by comparing the cell morphologies,cellular adhesive force and the cytoskeleton.A comprehensible exposition between the concave honeycomb surface and convex colloidal crystal array was innovatively presented.(5)A strategy for single cell trapping based on the novel BSA reduced 3-dimensional honeycomb graphene oxide films was developed.The resultant surface was hydrophilic in the air and superoleophobic underwater by combination of honeycomb roughness and water corona of amphiphic protein.In addition,the prepared BSA reduced GOHCM had been demonstrated successfully trapping cells which was ascribed by the BSA layer and the micro-nano hierarchical structure.It is conceivable that the BSA reduced 3 dimensional graphene oxide provides an convenient and cost-efficient for single cell trapping without the microfluidic technique and would be a powerful tool for cancer research.In the future,combining electrical properties of graphene,the prepared films exhibited potential and benefitting applications for the diagnosis and single cell chips.