Biological System Modification Based On Light-triggered Bioorthogonal Reactions

As an external stimulus with high spatial and temporal resolution,illumination has excellent biocompatibility,so it can dynamically regulate the spatial and temporal resolution of biological systems in a nondestructive way.In recent years,light-driven bioorthogonal reactions have been gradually developed,such as the UV-induced click reaction between tetrazole and electron-deficient olefin(TEPC)and visible lightinduced click reaction between phenanthraquinone and vinyl ether(DVPC).This makes it possible to modify biological systems based on light-triggered biorthogonal ligation reactions.In this thesis,we studied the modification of short peptide self-assembly system and protein structure based on TEPC and DVPC.In the first part of this thesis,a two-component supramolecular hydrogel was constructed based on tetrazole(TPI)modified short peptide TPI-GGF and phenanthraquinone(PQ)modified short peptide PQ-GFF,and the nanofibers in the hydrogel matrix were characterized by spectrum.Then,based on the TEPC photo-click reaction between TPI and monomethyl fumarate(MF)and the DVPC photo-click reaction between PQ and vinyl ether(VE),the possibility of covalently adhering to different molecules on self-assembled nanofibers was explored in the two-component hydrogel by ultraviolet and visible light regulation of different wavelengths.This study lays a foundation for the dynamic modification of hydrogel matrix based on the lightdriven bioorthogonal reaction to construct a three-dimensional cell microenvironment which can be dynamically regulated by light.In the second part,we studied the behavior of stem cells cultured in TPI-GGF and PQ-GFF two-component hydrogel with the change of microenvironment.By means of TEPC reaction between TPI and MF and DVPC reaction between PQ and VE,MFGGGHAV short peptide and VE-c(RGDf K)short peptide mixed in the hydrogel matrix were controlled to adhere to different nanofibers in the gel matrix.In the third part of the thesis,whether PDO,the reaction product of DVPC,can break the bond under the force is explored.Using snap-tag technology,we combined BG-PDO-BG(BPB)with(GB1)4-SNAP protein to construct SNAP-PDO-SNAP(SPS)protein polymer.Preliminary ultrasonic results showed that the BPB position in the protein polymer was broken.However,whether to fracture into the original phenanthraquinone and vinyl ether is still in process.In conclusion,this thesis mainly focuses on the biological application exploration of visible light-induced bioorthogonal reaction between phenanthraquinone and vinyl ether(DVPC).The successful construction of TPI-GGF and PQ-GFF two-component hydrogel provides a new direction for the study of the behavioral response mechanism of stem cells to the changes of biological elements in the microenvironment.The study of ultrasonic bond breaking of PDO,the product of DVPC photoclick reaction,is still in progress.