A system for simultaneous ultraviolet light and electromagnetic field exposure in in vitro experiments

Ultraviolet light (UV) is a common treatment for skin diseases such as psoriasis, but bears the risk of carcinogenic side effects. We have biological evidence that electromagnetic fields (EMFs) can act additively with UV so that new therapeutic protocols combining UV and EMF might be developed to improve psoriasis phototherapy. In this study we report on a system that allows in vitro experiments testing this hypothesis. For simultaneous exposure of cell cultures to UVB and EMF, we built Merritt coils with an integrated UV exposure system. The coils can be operated in a sham or experimental mode (up to 1.5 mT and 20,000 Hz). Two UV bulbs were fitted inside the coils for UVB doses between 100-1000 J/m2/nm. In the exposure area the EMF is uniform within 0.0038%. For exposure, the cells are cultured in standard culture plates and placed in a specifically designed box. The box holds two plates in a top chamber covered with a Saran Wrap lid (91% UV transmission) so that cells are exposed to UVB and EMFs. The bottom chamber holds two plates, where cells are screened from UVB and only exposed to EMFs. Temperature control is maintained (+/- 1 degree C) by airflow vents on the side of the box and a fan placed 25 cm away from the cell culture box. To maintain sterility within the box the vents are covered with a bacterial filter. The box lid has additional ventilation through two air direction changes to create an additional bacterial barrier similar to that in culture plate lids.