UV Treatment of Cells. SKU-1064 human fibroblast cells were exposed to a radiation dose of 60 mJ of UVA (λmax ) 360 nm) or UVB (λmax ) 300 nm) light for 1 min. Growth medium was removed just prior to UV exposure and immediately replaced with fresh medium after UV treatment. Cells were subsequently treated with different concentrations of PEs and incubated at 37 °C and 5% CO2 atmosphere.