During the in vitro creep of intervertebral discs,both applied loads and osmosis of solution influence their biomechanical behaviors.More specifically,the total displacement can be attributed to three parts:the elastic response during the loading period that results from instant tissue deformation;the nonlinear displacement during the creep period that is due to the poro-elastic fluid flow and visco-elastic deformation;and the swelling of discs that are affected by the osmolality.However,their respective contributions to the total displacement are unknown.To this end,this study aims to discern contributions of the above three parts in ex vivo experiments quantitively.Specimens were compressed for 4 h after 0.5 h preload.Displacement and strain were recorded and curve-fitted.The instant elastic displacement was positively related to the applied load,and its proportion rose from 18.09 to 21.46％as the load elevated.While the contribution of the net creep was inversely related to the applied load,dropping from 74.49 to 60.16％.An increase of 0.74 MPa of the osmolality induced a rise in displacement by 7.42-18.38％.Moreover,with the help of the non-contact measurement,researchers are able to know the contribution of each part quantitatively,which is of importance in understanding the creep mechanisms and developing biomaterials with mechanical mimicry of natural discs.

Mengying Yang;Yangyang Cui;Yu Zhang;Huakai Wu;Beibei Hu;Song Wang;Weiqiang Liu

Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China;Tsinghua Shenzhen International Graduate School,Tsinghua University,Shenzhen 518055,China;Biomechanics and Biotechnology Lab,Research Institute of Tsinghua University in Shenzhen,Shenzhen 518057,China;ACQTEC Instruments Technology(Shanghai)Limited,Shanghai 201706,China

仿生工程学报（英文版）

[1]Mengying Yang;Yangyang Cui;Yu Zhang;Huakai Wu;Beibei Hu;Song Wang;Weiqiang Liu-.Quantitative Characterization of the Elasticity,Net Creep,and Swelling of the Intervertebral Disc:An In Vitro Experiment)[J].仿生工程学报（英文版）,2022(04):1077-1086

poro,osmolality

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