Abstract 1749 Development of a UVB narrow beam source for Targeted Irradiation of NIH/3T3 mouse skin fibroblasts for Cancer studies

A portable UVB (ultraviolet B) narrow beam light source with a wavelength of 308 nm,1mm in diameter was developed that was capable of targeted exposure to irradiate NIH/3T3 mouse skin fibroblast cells. The source generates a directive UVB beam at specific wavelength of 308 nm, The diameter of the tube is about 1 mm where the light leaves the opening of the tube in one direction (like a laser beam) through a circular quartz window closing the tube from one end. The directed narrow UVB beam generated by the source enables the irradiation of controlled areas of the biological samples. UVB sources that provide narrow beam with a controlled power for research purposes are not commercially available currently. The UVB source was successfully used to target live NIH/3T3 mouse skin fibroblast cells grown as monolayers in wells of a 96-well plate. Cell viability was measured post-UV exposure by Neutral Red dye cytotoxicity assay. The results suggest that there was an increase in the relative cytotoxicity of skin fibroblasts at highest dose of UVB exposure (1620 mJ/cm2) with highest cell death recorded at 24 h post-UV exposure. The relative expression of p53 protein was determined following UV exposure with highest expression recorded at 48 hr. post exposure. Damage to DNA can result in mutations which lead to skin cancer. DNA damage resulting from UV exposure was assessed by measuring the formation of cyclobutane pyrimidine dimers (CPD). The results show an increase in the formation of CPD immediately following UV exposure of 3T3 fibroblasts skin cells as compared to cells not exposed to UV light. To conclude, a UVB (ultraviolet B) narrow beam light source was developed and was used for targeted irradiation on a small number of skin cells grown in-vitro as monolayers in 96-well cell culture plates. The source generates a directive UVB beam with a small circular cross-sectional area in a range of 1 mm. The source was successfully used for skin cancer studies on NIH/3T3 mouse skin fibroblast cells. Financial support was provided by Faculty Development Grant, Milwaukee School of Engineering, Milwaukee, WI 53202