Experimental Investigation And Simulation Of Dynamic Chemical Gradient Establishment In Gelatin Crosslinked Hydrogel

Active substances(such as growth factors or enzymes)in an organism have specific temporal and spatial distribution characteristics(time-space distribution or spatiotemporal pattern).These active substances dominate the process of biomorphogenesis.Understanding the laws of these forms helps to understand the origins of the diverse shapes of living things.This is also of great significance in the fields of tissue engineering,embryo engineering and medicine.Therefore,it is necessary to explore the law of spatial and temporal distribution of active substances.In order to solve the above problems,the chemical gradient pattern was established in gelatin hydrogel(GelMA)by microfluidic technology.The chemical gradient pattern of ?-cyclodextrin modified polyacrylic acid(pAA-CD)physical gel was also explored.The process of formation.The article compares the characteristics of two different chemical gradient patterns and summarizes the role of supramolecular action in pattern formation.Several microfluidic devices with different boundary conditions were also constructed in the experiment.Then the process of pattern formation was observed and the rules were summarized.Firstly,a simple scheme for preparing a microfluidic device was designed experimentally to provide the necessary basic platform for subsequent experiments.The experiment used a microfluidic device to observe the chemical gradient pattern formed under free diffusion.At the same time,pAA-CD physical gel was introduced into the hydrogel system as a carrier for the supramolecular action site.Comparing the patterns formed by the two,it was found that the supramolecular effect not only extended the time scale of the pattern,but also contributed to the formation of an ordered structure.Theoretical discussions have shown that supramolecular action introduces a nonlinear factor in this process;and this nonlinear factor contributes to the formation of ordered structures.Two chemical gradient patterning systems with different boundary conditions were established in the experiment.In these systems,a central region(triangles and squares)is formed as a pattern;a diffusion entrance is provided on several vertices of the central region(three vertices in a triangle and four vertices in a square).Experiments have revealed the presence of a triangular and cruciform edge in the central region.For this triple-diamond and cruciform structure,this structure also appears in the ovary of the plant Podophyllum emodi.This shows that the experimentally established patterning system reconstructs some special phenomena in nature.At the same time,theoretical calculations reveal the mechanism of chemical gradient pattern formation under these special boundary conditions.