Research On Assembly And Regulation Strategies Of Biomaterials Based On DNA Nanotechnology

Biomaterials perform various complex but ordered assembly or disassembly behaviors through specific identification and regulation methods.Exploring their specific mechanisms is the basis for understanding various higher-order life activities in organisms.Thanks to the rapid development of DNA nanotechnology,various synthetic DNA molecules can be used to recode and regulate the assembly behavior of biomaterials in vitro.On the one hand,it can be combined with natural biomolecules to achieve specific interactions between molecules by virtue of the unique biochemical properties of DNA.On the other hand,synthetic DNA structures can be directly used as the basic elements for dynamic and controllable assembly and disassembly.However,in the current study,the efficiency of assembly and disassembly between biomaterials still needs to be improved.Meanwhile,its regulation methods mainly rely on some traditional methods(such as p H,ions,etc.),the efficiency and intelligence are not ideal,and they face problems such as complexity and safety.Therefore,it is urgent to develop some new strategies for efficient,intelligent and controllable assembly and regulation of biomaterials.With the rapid and diversified development of biotechnology,some new molecular tools are expected to solve the above scientific problems.For example,the CRISPR-Cas12 a system developed in recent years not only has the function of specific recognition,but also has efficient trans-cleavage activity after activation,which is expected to achieve efficient dissociation and intelligent regulation of biomaterial assemblies.In addition,the light-controlled technology with the advantages of non-invasiveness,high temporal,spatial resolution,and simple operation is also an external stimulation method worth exploring.Therefore,in this research paper,in order to develop more efficient and intelligent strategies,we chose DNA rectangular origami and cells as the research object,combined with CRISPR-Cas12 a technology and light-controlled method,developed some new strategies for efficient,controllable and specific assembly and regulation.The specific research contents are as follows:(1)In Chapter 2,based on a simple three-strand hybridization system,we mixed and annealed monomers OA and OB to obtain the pre-designed target products,DNA origami dimer(Dimer-AB).At the same time,the assembly yield of the dimer structure will be greatly improved by further optimizing the experimental conditions.Therefore,the experimental design of this work can not only realize the efficient assembly of DNA origami dimer products,but also ensure its structural stability and specificity,which provides a basis for the assembly of multi-module polymers.(2)In Chapter 3,in order to improve the disassembly efficiency of oligomers,we took the DNA origami dimer designed in Chapter 2 as the transcleavage substrates and successfully demonstrated the efficient disassembly process of dimer to monomer by using the emerging CRISPR-Cas12 a technology.Meanwhile,the regulation of protein activity can help to control the dissociation behavior of dimer in Cas12 a system.This work makes full use of CRISPR-Cas12 a to realize the efficient and intelligent disassembly of oligomers,which provides a new design idea for the controllable dissociation of biomaterial assemblies.(3)In Chapter 4,based on the targeting affinity of aptamer,we constructed a light-activated self-locking hairpin structure,S-sgc8,on the cell surface,which regulates the recognition and binding of aptamer to specific receptors on target cells through light stimulation,so as to further realize the controllable and specific assembly between cells.The light-controlled method in this work has the advantages of simple design,convenient operation,remote manipulation and low cytotoxicity,which provides a reference method for the dynamic regulation of specific interactions between cells.