Photoisomerization of Provitamin D in Hydrogel Matrix

Abstract

Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however, hampers fat-soluble biomolecule incorporation. We synthesized N-isopropylacrylamide (NIPAAm)-and Acrylamide (AA)-based hydrogels with hydrophilic-lipophilic balance that under specific conditions permit homogeneous incorporation of provitamins D 3 (7-dehydrocholesterol) and D 2 (ergosterol) dissolved in ethanol. Similarity of provitamins D photoisomerization in such hydrogel matrices with the photoreaction in ethanol shows great potential of the novel material for personal dosimetry of biologically active 'antirachitic' UV radiation.

Three operation modes of the vitamin-D-biodosimeter

“…Secondly, multiple light reflections from the internal walls of the cuvette violate the "cosine response" conditions for UV monitoring. To resolve these problems hydrogel matrices with incorporated 7-DHC molecules were prepared in the form of films of 2mm thickness 11 . It was found that the absorption spectra of 7-DHC in hydrogel matrix is almost identical to the spectrum in ethanol solution that allowed the use of developed software for processing the spectra with the aim of concentration analysis 11 ( Figure 3).…”

Metrology of the vitamin-D-synthetic activity of UV lamps

“…It appeared that the absorption spectrum of 7-DHC in the film is almost identical to its spectrum in ethanol that allowed the concentration analysis (Fig. 3) [12]. …”

“…To avoid the inconvenience associated with the use of liquid solution, 7-DHC molecules were incorporated into the hydrogel matrices in the form of 2 mm thick films [11]. It appeared that the absorption spectrum of 7-DHC in the film is almost identical to its spectrum in ethanol that allowed the concentration analysis (Fig.…”