| Bone is a porous structure containing both solid and liquid phases.When the macroscopic bone is subjected to mechanical loads,the fluid around the bone cells in the micro-scale lacunarcanalicular system(LCS)is usually subjected to the pressure and the electric field,the resulting fluid flow will stimulate the bone cells and their attached primary cilium and osteocyte process in contact with the fluid.The purpose of this research is to study the distribution and influencing factors of various mechanical signals sensed by cells in the two fluid environments of the rectangular channel and the lacunar-canalicular system system.With the help of Comsol multiphysics finite element software,this article mainly uses finite element analysis to explore the mechanical perception of porous viscoelastic cells under pressure-electricity synergic driven,and it is helpful to combine biomechanical principles to guide osteoporosis,osteoarthritis and other related diseases Treatment and bone reconstruction after bone injury.Cells usually live in a complex physiological environment.The primary cilium,which is an important organelle of the cell,is attached to the cell surface and is regard as an important mechanical signal sensor to help living cell receive various external mechanical signals,the primary cilium is considered to be closely related to physiological activities such as metabolism,development,division and proliferation of the living cell.In order to study the mechanotransduction behavior of the living cell and the primary cilium growing on its surface in a microfluidic environment,Chapter 2 established the adherent cells within a rectangular microfluidic control channel model system,cells with poroviscoelastic properties are in a culture solution driven by the pressure gradient and electric field driven loads.The mechanical signal responses of cytoplasm and nucleus of cells such as the stress,strain,pore fluid pressure and pore fluid velocity under oscillatory laminar flow were investigated,as the mechanical signal’s receptors of the living cell,the primary cilium’s biomechanical behavior was quantitatively investigated.In order to study the cellular mechanics signal response to fluid stimulation in the lacunar-canalicular system,the third chapter of established the lacunarcanalicular system containing cytoplasm,cell nucleus,osteocyte processes,primary cilium and collagen hillocks.The cell model investigates the mechanical behavior of the solid and liquid phases of porous viscoelastic cells when the fluid flow in the lacunar-canalicular system under pressure-electricity synergic driven.The results of chapter 2 show that the mechanical response of the living cell under an oscillating laminar flow field has the same oscillating law as the synchronous external the pressure gradient and electric field driven loads.The permeability of the living cell is one of the most important physical parameters affecting the cell’s poroviscoelastic behavior.Primary cilium is the main mechanoreceptor organelle.The living cell can adjust their mechanical sensitivity(stress-affected zone)by changing the length and diameter of its primary cilium.With the increase of the length of the primary cilium,the flexural rigidity of the primary cilium decreases,but the sensitivity increases.The establishment of the model provides a basis for further research on the microscopic mechanisms of cell growth and differentiation under the loading of microfluidic shear stress,and also provides theoretical technical support for testing the microstructure mechanical properties of the cell anticipates(protein chains such as primary cilium).The results show that osteocyte process and primary cilium are both mechanically sensitive components of cells.The growth direction and number of osteocyte processes will also affect the mechanical signals of the cell body,and the mechanical signals of the cells when the osteocyte processes grow along the long axis of the cell.It is stronger than the case where the osteocyte processes grow along the short axis of the cell.The more osteocyte processes and canaliculus,the stronger the mechanical signal the cell perceives.The presence of collagen hillocks strengthens the mechanical perception of osteocyte processes,and the greater the elastic modulus of collagen hillocks,the better the effect.The mechanical perception ability of primary cilium showed position dependence but not length dependence.The establishment of the model is helpful to study the influence of cell microstructure on cell mechanics. |
