Molecular Behavior Regulation Of Natural Collagen-ionic Liquid And Heterogenous Assembly

Collagen is one of the most abundant protein species in multicellular organisms.It is widely present in the tissues and organs of animals such as bones,Achilles tendons,and skin.The unique three-helical molecular structure of natural collagen confers superior biomechanical properties and biological stability compared to other types of proteins.At the same time,as the main component of the extracellular matrix(ECM),excellent biocompatibility and biodegradability have also become natural collagen unique performance labels.It is precisely because of this that in recent years,collagens have been found without exception in technological advances and cutting-edge research involving clinical medicine,life sciences,and biomaterials.Self-assembly/fibrosis is one of the most important molecular characteristic behaviors of natural collagen and directly affects the structure and properties of collagen-based materials.At present,collagen gel/collagen fibers based on the behavior of natural collagen self-assembled molecules have been successfully applied in food engineering,biomedicine,and biological materials.However,in many fields of application of collagen,various fields have different performance requirements.The inherent molecular behavior of natural collagen often brings single properties,and it is difficult to meet the performance requirements in different fields,thereby limiting the scope of application of collagen.Based on this,this paper discusses the regulation of ionic liquids and heterologous assembly on the molecular behavior of collagen and further optimizes the performance of self-assembly products,this provides new ideas for the expansion of the scope of application of natural collagen and the development of novel collagen-based biomaterials.Environmental factors are one of the important factors affecting the behavior of natural collagen self-assembled molecules,and they are also the main means to optimize and regulate the structure and properties of collagen-based biomaterials.In view of this,using the enzyme-soluble collagen extracted from grass skin as a template,the influence of ionic liquids on the behavior of collagen self-assembled molecules and gel properties was investigated.Self-assembly kinetics analysis showed that the introduction of ionic liquids inhibited the molecular behavior of collagen self-assembly,and the inhibitory effect was closely related to the concentration and type of ionic liquids.Scanning electron microscopy tests show that the collagen self-assembly product in ionic liquid media has a larger fiber size than conventional buffers(PBS).At the same time,differential scanning calorimetry analysis showed that the thermal stability of collagen fibers can be significantly improved when self-assembled in an ionic liquid medium.Furthermore,the intervention of the ionic liquid effectively enhances the mechanical strength of the collagen gel.Heterologous collagen blending is an important technique for regulating the behavior of collagen self-assembled molecules,and it also provides new ideas for the performance improvement and optimization of collagen-based biomaterials.However,there is no effective monitoring method for the assembly of allogeneic collagen.To this end,this part of the use of graphene oxide quenched the special properties of fluorescence,developed a simple and efficient method of monitoring the assembly of heterologous collagen,and further achieved the controllable adjustment of the thermal stability of collagen fibers.Fluorescence spectrum analysis showed that FITC-labeled porcine dermal collagen adsorbed on graphene oxide surface resulted in fluorescence quenching.After the introduction of grass carp collagen,heterologous assembly was performed to make FITC-labeled porcine collagen from graphene.The surface was peeled off and the fluorescence recovered;however,under non-heterologous assembly conditions,the fluorescence intensity did not change much.At the same time,fluorescence kinetics tests further confirmed that heterologous assembly is a prerequisite for the change of fluorescence intensity.Differential scanning calorimetry analysis showed that the collagen fibers formed from the heterologous assembly of pig skin collagen and grass carp skin collagen showed completely different thermal stability from that of a single collagen fiber.Furthermore,atomic force microscopy observations also provide graphical evidence for heterologous assembly of pig skin collagen and grass carp collagen in graphene oxide systems.More importantly,by varying the concentration of grass carp skin,different collagen fibers with different thermal stability were constructed,and the denaturation temperature was linearly related to the concentration of grass carp skin.Thus,any adjustment of the thermal stability of the collagen fiber was successfully achieved.