Provitamin D Doped Silica and Polymeric Films: New Materials for UV Biosensor

The original technologies of growing silica films, impregnated with 7-dehydrocholesterol (provitamin D3) on quartz substrates and free transparent films on the basis of polyvinyl alcohol and polyvinyl butyral have been developed. Provitamin D photoisomerization in the films under UVB irradiation was investigated by UV absorption spectroscopy. Remarkable changes in the absorption spectrum of 7-DHC were observed in silica and polyvinyl alcohol films as compared with ethanol solution, only in polyvinyl butyral film the spectrum was very nearly, while the spectral kinetics of 7-DHC photoisomerization in all the films was different from ethanol. We suggest that several films have potential as UV dosimeters to measure accumulated 'antirachitic' UV dose in the same manner as erythemic UV dose is measured by commonly used polysulphone film.