RESUMO
Objective To study the mechanical properties of collagen molecules by molecular dynamics simulation,and to determine the relationship between the mechanical properties of the microstructure of cartilage and the macroscopic mechanical properties. Methods Obtaining the collagen molecular model from the protein database and using GROMACS molecular dynamics simulation software,an analog box was built with a size of 24 nm× 3.2 nm × 3.2 nm. The simulation system contained 6 719 water molecules, 20 sodium ions and 20 chloride ions. This solution was equivalent to a saline environment. The uniaxial tensile simulation of collagen molecules was executed under the conditions of different temperature,different tensile rates and different pressures in this environment.Results When the temperature was constant, the tensile rate and the elastic modulus of collagen increased; when the tensile rate was certain, the temperature of the simulation system rose while the modulus of elasticity decreased;under the conditions of certain temperature and tensile rate, the pressure of the system gradually increased,and its modulus of elasticity decreased gradually. Conclusion Through the uniaxial tensile simulation of collagen molecules under different conditions,the mechanical laws of collagen molecules are obtained.There is a certain correlation between the elastic modulus and the tensile strain during the stretching process,and a way of thinking is provided on the study of the correlation of cartilage rate from the microscopic aspect.