RESUMO
BACKGROUND: Under the pressure of mechanical action, the culture membrane will be stretched and cause the deformation of cells which adhere to the surface of culture membrane. According to this, growth regularity in different external force environments will be observed; however, how to determine the load distributions on the whole culture membrane still remains unclear. OBJECTIVE: Photomechanics method was applied for determining the out-plane displacement so as to obtain the strain distributions of the cell culture membrane. DESIGN, TIME AND SETTING: Contrast study was performed at the Photomechanics Laboratory, School of Mechanical and Automation Engineering, Shanghai Institute of Technology from March to August 2008. MATERIALS: Culture membrane which specially used for biomedicine was made by Dow Coming Corporation, USA and the type was Q7-4750. The dimension and mechanics properties were as follows: diameter = 100 ram, thickness = 150-160 μm, modulus of elasticity E = 2.14 MPa, and Poison's ratio = 0.48. lines per millimeter; phase shift set was controlled by manual and 5 marks equal 0.1 mm; CCD camera was used for capturing moire patterns. Finally, phase was transformed into displacement so as to obtain three-dimensional appearance and manner. MAIN OUTCOME MEASURES: Out-plane displacement information, and deflection of culture membrane including displacement and strain. RESULTS: The three-dimensional profiles of culture membrane after deformation were constructed by image processing method and the out-plane heights could be obtained. Corresponding to the total strains of 1%, 10%, 20%, and 25% for the culture membrane, the displacement of highest point was 2.28 mm, 8.32 mm, 12.12 ram, and 13.52 mm, respectively. The error was 3.5% through comparing the measured heights of culture membrane with the heights which was known for the culture membrane. It indicated that this experiment method was highly sensitivity. According to the out-plane displacements, the strains distributions along symmetrical axis were calculated and the distributions of strain were shown by parabolic curve. displacement distributions of culture membrane is obtained and shown displacement contour. Namely, the out-plane displacement of center for the membrane has the maximum heights, and the strains distributions are shown parabolic curve.