Study On Three-dimensional Traction Force Of Single Cells Based On Foldable Microplates

Cells exert cell traction force(CTF)on the surrounded extracellular matrix(ECM)or neighboring cells.CTF play critical role in numerous biological processes,such as inflammation,wound healing,angiogenesis and tumor metastasis.Quantitative characterization of CTF is crucial for understanding intrinsic mechanobiological behavior of cells in physiological and pathological environments.At present,the experimental techniques and theoretical models used to characterize CTF are based on the deformation of flexible substrate caused by cells and the constitutive relation between CTF and substrate deformation,moreover,this type of method is usually used to calculate the distribution of CTF produced by cell adhesion in two-dimensional and quasi-static environment.Thus,the development of experimental technique and measurement methods that can directly measure and analyze three-dimensional CTF will help to expand the understanding of the interaction between cell-cell or cell-ECM.In this dissertation,a foldable microplate for single cell culture system is fabricated,a three-dimensional CTF model for cell growth is developed.Additionally,the three-dimensional force of cell on the folding microplate is theoretically deduced.The main work is as follows:1.Patterned and multi-coated homogeneous Parylene-C microplates were designed by MEMS and biomolecular coating modification technology.Parylene-C microplate array with3 μm thickness,both 50 μm sides length and 100 nm thickness intermediate connection was fabricated through optimizing the preparation process of microplate.CTF experimental platform for three-dimensional traction analysis of a single living cell is designed.These results provide an ideal experimental platform for analyzing CTF in three-dimensional state,and also provides a new technology for recapitalizing the mechanical microenvironment of cell matrix and studying the mechanobiological behavior of cells.2.The surface morphology,surface roughness,hydrophilicity/hydrophobicity and cell compatibility of Parylene-C microplate were characterized.The surface conditions of Parylene-C microplate modified by Co L-I were optimized,the surface morphology of Parylene-C microplate was significantly improved,and the hydrophilicity,cell adhesion and proliferation rate of Parylene-C microplate surface were significantly improved.These results indicated CTF produced by cell folding microplate is related to the cell microenvironment,which provides an experimental technology for the study of CTF in the three-dimensional state of living cells.3.Mechanical model of single cell three-dimensional CTF in microplate folding process was obtained through theoretical derivation and finite element simulation.The calculation method of traction force of single cell in three-dimensional state during microplate folding is given.These results provide a calculation method of cell traction which is more similar to in vivo state and a new method to quantitatively describe the evolution of CTF in the process of cell growth.4.The traction force values of four types of cells in two three-dimensional spaces corresponding to the initial and final folding states of the foldable microplate are provided.The relationship between the folding angle of microplate and CTF,the effect of cell type on the folding rate,cell spreading area and the position of long axis on the detachment of microplate from the substrate were analyzed.These results indicated that CTF in the process of cell folding are not only related to cell types,but also closely related to the dynamic changes of cell morphology.These results provide reference for the development of universal CTF theory and experimental measurement technology.