Using selected uniform cells in round shape with a micropipette to measure cell adhesion strength on silk fibroin-based materials

As cell adhesion to material surface is one of the important responses of living tissue to implant devices, it is necessary to establish effective and quantitative methods to evaluate the cellular affinity of materials. In this paper, the useful method for measuring and distinguishing the cell adhesion strength on different material surfaces with the micropipette technique was improved. The uniform cells in round shape (UCR) were selected from a number of adhered cells on the test surface to measure the detachment forces during initial adhesion stage. High reproducibility and sensibility could be obtained to distinguish small differences in the adhesiveness of endothelial cell on the silk fibroin-based materials. The effects of UCR size, UCR amount, seeding time and seeding temperature were investigated. For comparable purpose, parallel-plate flow chamber and MTT assays were also conducted to measure the interaction between substrate and a large number of cells. Results acquired from three methods were in accordance with each other well. It is suggested that this rapid UCR method is effective to compare the cell adhesion strength on different material surfaces and a few UCR might represent a large number of cells to evaluate the cellular affinity of biomaterials quantitatively.