Biomedical Application Of DNA Nano-materials

Based on the various excellent performances of DNA materials,the purpose of this dissertation research is to use the microscopic and macroscopic DNA assembly structure to achieve its further application in the biomedical field,which can lay a solid foundation for the further application of DNA nanotechnology.As to the application of microscopic DNA assembly structure,we employed the DNA dendrimer assembly as carrier for B-cell epitope MUC1 glycopeptide(Tn00)and helper T-cell epitope(T12)assembly.We used the structures as the antigen simulation objects to explore the stimulation effect of immunity in mice.At the same time,CpG,the specific DNA single sequences were introduced in the structures as the immunostimulants to enhance the immunity.With the “click chemistry”,the azide modified epitope peptide was linked with alkynyl modified CpG.Through the programmed assembly,we modified two epitope peptides-CpG compounds on the assembly surface of G3.Based on the continuous immune stimulation on mice via the epitope compounds,we examined its immune effect.Meanwhile,in order to use the assembly structure as the carrier of small molecule of drugs,we choosed tetrahydroisoquinoline,an alkaloid structure widely existed in the natural products,as the target small molecular to carry on the structure.We accomplished a synthesis research of optical activity of tetrahydroisoquinoline.In macroscopic applications of DNA assembly,we applicate the DNA hydrogel in tissue engineering.Embedding the target cells in DNA hydrogel,we developed a new "brick to wall" strategy.Based on self-healing character of DNA hydrogels,it implements the unitized module combination,which meets the requirements of tissue engineering in building more complex organization simulation.Through the three-part experiments,we verified the feasibility of this approach.By the bio-compatibility judgement of embedded cells in the hydrogel and the self-healing experiment of cell module,we confirmed the necessary properties of DNA hydrogel system in this strategy.By introducing Trans-well model experiment,we further proved that the DNA hydrogel permitting macromolecular transferring and preliminarily verified the cell migration in DNA hydrogel.With fluorescence labeling,we tracked and studied the cell behavior in different hydrogel modules under different conditions,which further proved that the cell growth and migration will not be blocked among different modules.We proved the new strategy of "brick to wall".We also attempted to introduce the DNA hydrogel and the strategy of "brick to wall" to 3D printing devices.We transformed the business-purchased PLA 3D printer as the biological printing equipment platform,and realized the microtubule fine print device with sodium alginate.That offered us the experiences and basic protocol for the development of DNA hydrogel 3D printing,as well as,for the more convenient and efficient future application of the strategy of "brick to wall".