Effect of light-emitting diode wavelengths on human dermal fibroblasts for phototherapy

Recently, light-emitting diode (LED) technology has been utilized by a large number of dermatologists to promote rejuvenation in patients with aged and photoaged skin. One of the most important parameters influencing the therapeutic effects of LED is its wavelength. In this study, we have developed an LED stimulation compartment to study the effect of the light at 630, 680 and 830 nm on human dermal fibroblast proliferation and their expression levels of collagen type I. Significantly higher proliferation rates were observed in the fibroblast culture irradiated with LEDs. Specifically, red light (630 and 680 nm) yielded higher cell numbers, in comparison to infrared light (830 nm), which could be effectively used to stimulate the healing process and promote rejuvenation. Interestingly, 680 nm LED was shown to increase the level of collagen type I in dermal fibroblasts which could eventually lead to higher production of collagen, an important structural protein responsible for youthful skin appearance. Our findings suggest that 680 nm LED had a photo-therapeutic effect towards human dermal cells which could potentially be used to treat aged and photoaged skin.