The effects of low frequency electromagnetic fields on the proliferation of epidermal stem cells cultured on two different scaffolds

Abstract

Objective To observe the effects of low frequency electromagnetic fields (LFEMFs) on the proliferation of human epidermal stem cells (hESCs) cultured in a three dimensional environment so as to provide an experimental basis for applying LFEMF in skin tissue engineering.Methods hESCs from human prepuces were isolated and purified by the method of rapid adherence to collagen type ⅣV. They were grafted into a type-I collagen sponge or chitosan scaffold in vitro, and then stimulated with different frequencies of LFEMF ( 1 Hz, 10 Hz or 50 Hz) at a magnetic field intensity of 5 mT for 30 min/d. The cells' growth and proliferation were tracked using hematoxylin and eosin (HE) and diamine pheny1 indole (DAPI) staining and observed under the scanning electron microscope at different time points ( on 2nd, 7th, 10th and 14th days of LFEMF intervention). The amounts of cell proliferation at every time point were analyzed and compared.Results LFEMFs of different frequencies showed significantly different efficacy in promoting hESC proliferation. The two scaffolds also showed significantly different effects.By the 10th day, hESCs had grown significantly better on collagen sponge scaffolds than on the chitosan ones. All LFEMF frequencies could promote proliferation of hESCs, but the differences in their effects were statistically significant.Conclusion Collagen sponge may be a preferable scaffold for hESCs cultured in vitro. Rapid proliferation of ESCs in three-dimensional settings can be promoted by LFEMF intervention. LFEMF has relatively great potential in skin tissue engineering. Key words: Low frequency electromagnetic fields; Epidermal stem cells; Proliferation; Collagen sponge scaffolds; Chitosan scaffolds; Tissue engineering