A method of isolating epithelial cells from a human skin tissue or internal organ tissue using trypsin and ethylene-diamine tetraacetic acid (EDTA) simultaneously with the application of magnetic stirring, a method of preconditioning isolated biological cells by the application of physical stimulus, i.e., strain, are provided. Epithelial cells can be isolated by the method with increased yield, colony forming efficiency (CFE), and colony size. Also, the increased percentage of stem cells in isolated cells is advantageous in therapeutic tissue implantation by autologous or allogeneic transplantation. In skin cells preconditioned by the application of strain, cell division is facilitated, and the secretion of extracellular matrix components and growth factors and the activity of matrix metalloproteinases (MMPs) are improved. When preconditioned cells are implanted by autologous or allogeneic transplantation to heal a damaged tissue, the improved cell adhesion, mobility, and viability provides a biological adjustment effect against a variety of stresses or physical stimuli which the cells would undergo after implantation, with improved capability of integration into host tissue, thereby markedly improving the probability of success in skin grafting.
