| The construction of three-dimensional tissue engineering scaffold is an important approach to realize the application of macroscopic supramolecular self-assembly in tissue engineering.Our research group successfully constructed 3D tissue engineering scaffolds based on supramolecular interaction,and after surface modification of those scaffolds we got a good adherence state of the cells.However,one of the problems that needed to be solved first was that the stability of the 3D tissue engineering scaffolds based on weak supramolecular interaction was not enough.They were easy to disassemble in the process of cumbersome cells culture,so that the next work could not be carried out fluently.This paper was just to solve this problem as the starting point.We introduced one kind of covalent bonds-disulfide bond into the macroscopic assembly system as a new kind of macro-assembly driving force,which has the advantages of bioactivity and compatibility,mild experimental conditions and easy operation,to improve the stability of the assemblies.(1)We validated the feasibility of the experiment on macroscopic scale building blocks,which proved that use disulfide bonds could exactly achieve the assembly of building blocks.The force between the assembly was as high as 1570 N/m2,which was much higher than that of the traditional supramolecular interactions,indicating that we plan to use disulfide bonds to improve the stability of tissue engineering scaffolds was feasible.(2)Because the association rate constant of disulfide bond was very small(2.9M-1s-1),so it took a long time to get a stable assembly and greatly delay the progress of the experiment.In order to solve this problem,we further put forward a "double-locking" strategy which introduced a host-guest interaction of cyclodextrin and azobenzene(CD-Azo)into the disulfide bond system.By use of the rapid response of CD-Azo(108 M-1s-1)to assemble the building blocks in a shorter contact time,and then disulfide bonds gradually formed and the stability of assemblies also improved.The assemblies with "double-locking"structure could also achieve a selective disassembly.The results of qualitative and quantitative characteriations of assembly and disassembly proved our assemblies with "double-locking" structure were meanly formated by disulfide bonds and CD-Azo host-guest recognition.Through the introduction of disulfide bonds and "double-locking" strategy,we can not only hope to improve the stability of tissue engineering scaffolds,but also provide a universal self-assembly strategy for macroscopic assembly based on other types of interactive forces with small binding rates constant. |
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