Quantitative Research On Cell Adhesion Force With A Nanorobotic System

Cell adhesion is a fundamental phenomenon that is extremely important to all multicellular and unicellular organisms and plays a significant role in tissue growth,intercellular communication,cell migration,metabolism,inflammation and infection.The research of cell adhesion will help to reveal the mysteries of physiological phenomena,promote the birth of new disease diagnosis and treatment,promote the further development of nanobiomechanics,and even provide the necessary information for biological genetics.In many methods and techniques,Atomic Force Microscope(AFM)has become one of the most widely used research methods in nanobiomechanics because of its high accuracy,wide range and its ability to detect directly in physiological environment.In this paper,the adhesion of mammalian cells was studied by improved AFM single-cell force spectroscopy based on the self-developed nanorobot.While maintaining the high accuracy of AFM single-cell force spectroscopy,the chemical modification of traditional probes is replaced by adsorbing cells using hollow probe,which improves the test efficiency of cell adhesion and provides new test techniques and methods for cell mechanics.The main research contents include:Firstly,this paper improves the traditional AFM single-cell force spectroscopy,using hollow probe instead of the traditional AFM probe.A hollow probe pneumatic device was designed to generate negative pressure adsorbing cells in the hollow probe,which reduced the time taken to fix the cells and calibrate the probe and improved the efficiency of the force measurement.At the same time,the method allows the cells to contact the substrate for a long time,expanding the measurement range of adhesion.Secondly,the processes of aspirating and pulling cells through hollow probe were simulated.Based on the film-liquid continuum adhesion model,the mechanical model of adherent cells was proposed and established.The effect of inner diameter of the probe on the cell deformation and stress distribution was investigated by finite element simulation.Then,this paper analyzes the dissociation reaction of adhesion molecules under external force.Based on the Brownian kinetic theory of bonds dissociation under force in liquid,the characteristics of adhesion molecular bonds in the process of hollow probe pulling cells were analyzed.The influence of external force and its loading rate on the dissociation rate,longevity and strength of adhesion molecular bonds was obtained.Finally,the improved AFM-single cell force spectroscopy was used to measure the precise adhesion of cells to the substrate rapidly,which demonstrate time and probe velocity dependence on cell adhesion.Based on the nanorobot system,the improved AFM-single cell force spectroscopy can perform three-dimensional operation to test cell adhesion in the liquid environment,which not only has a driving effect on nanobiomechanics,but also provides a new approach for nanoscience research.