An Investigation On Measuring Young’s Modulus Of Low-elasticity Hydrogels

Cell structure and function which is in vitro conventional cell culture,is different from the cell in vivo.The main reason is that three-dimensional environment is different from the solid/liquid interface in a hardness petri dish,and the mechanical hardness of extracellular matrix is different from hardness petri dish.The mechanical properties of cellular environment play an important role to the behavior of the cells,such as cell proliferation,cell differentiation,cell migration and cell shape.Hydrogel is a kind of new functional polymer materials,which can swell in the water,keep water and be insoluble in water with three dimensional network structure.Three-dimensional structure of the hydrogel,which is high water content,and cellular environment in the body is similar to the structure and function,thus hydrogel often simulates the effect of extracellular matrix in cell culture.Adjusting the mechanical properties of hydrogels simulates the cell environment of different tissue.A determination mechanical property of hydrogel is the key technology to control mechanical properties of the hydrogel.In this paper,its mechanical property determination is carried out by the following three aspects: first,on the basis of the submerged tensile method,it deducts the buoyancy of weight,to improve the precision of the measurement result;Second,three new kinds of hydrogel microsphere verifies indentation method formula,which is based on the theory of Hertz,using numerical simulation method and optimization algorithms to get optimal new parameters;Third,puting forward new formula included transverse deformation is based on the gravity work,the unknown parameters in the formula are obtained by young’s modulus of microspheres indentation method,and fit the formula.The results of the study are as follows: the measurement precision of the new tensile system,which is included in the weight,is superior to the previous system;The new formula of the Hertz contact theorem obtained by tensile method can be applied to five kinds of hydrogels,and the calculation error is small;indentation gravity method is based on the gravity acting and included transverse deformation,and fitting out the new formula can accurately calculate the young’s modulus of hydrogel.Compared to the tensile method,Er is less than 5%.