Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix

Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix

A new approach to the problem of personal UV biodosimeter is described. Nematic liquid crystal (LC-805) is converted into induced cholesteric phase using photosensitive chiral dopant of steroid biomolecules (7-dehydrocholesterol (provitamin D3) or 7-DHC-benzoate). Significant changes in optical char...

Повний опис

Збережено в:
Бібліографічні деталі
Дата:1999
Автори: Dyadyusha, A.G., Gvozdovsky, I.A., Salkova, E.N., Terenetskaya, I.P.
Формат: Стаття
Мова:English
Опубліковано: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 1999
Назва видання:Semiconductor Physics Quantum Electronics & Optoelectronics
Онлайн доступ:http://dspace.nbuv.gov.ua/handle/123456789/120261
Теги: Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Цитувати:Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix / A.G. Dyadyusha, I.A. Gvozdovsky, E.N. Salkova, I.P. Terenetskaya // Semiconductor Physics Quantum Electronics & Optoelectronics. — 1999. — Т. 2, № 4. — С. 91-95. — Бібліогр.: 11 назв. — англ.

Репозитарії

Digital Library of Periodicals of National Academy of Sciences of Ukraine
id irk-123456789-120261
record_format dspace
spelling irk-123456789-1202612017-06-12T03:04:35Z Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix Dyadyusha, A.G. Gvozdovsky, I.A. Salkova, E.N. Terenetskaya, I.P. A new approach to the problem of personal UV biodosimeter is described. Nematic liquid crystal (LC-805) is converted into induced cholesteric phase using photosensitive chiral dopant of steroid biomolecules (7-dehydrocholesterol (provitamin D3) or 7-DHC-benzoate). Significant changes in optical characteristics of the LC films depending on the duration of UV exposure are observed as a result of UV initiated photoisomerizations that change helical twisting power of dopant molecules. 1999 Article Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix / A.G. Dyadyusha, I.A. Gvozdovsky, E.N. Salkova, I.P. Terenetskaya // Semiconductor Physics Quantum Electronics & Optoelectronics. — 1999. — Т. 2, № 4. — С. 91-95. — Бібліогр.: 11 назв. — англ. 1560-8034 PACS: 42.79.K http://dspace.nbuv.gov.ua/handle/123456789/120261 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
description A new approach to the problem of personal UV biodosimeter is described. Nematic liquid crystal (LC-805) is converted into induced cholesteric phase using photosensitive chiral dopant of steroid biomolecules (7-dehydrocholesterol (provitamin D3) or 7-DHC-benzoate). Significant changes in optical characteristics of the LC films depending on the duration of UV exposure are observed as a result of UV initiated photoisomerizations that change helical twisting power of dopant molecules.
format Article
author Dyadyusha, A.G.
Gvozdovsky, I.A.
Salkova, E.N.
Terenetskaya, I.P.
spellingShingle Dyadyusha, A.G.
Gvozdovsky, I.A.
Salkova, E.N.
Terenetskaya, I.P.
Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix
Semiconductor Physics Quantum Electronics & Optoelectronics
author_facet Dyadyusha, A.G.
Gvozdovsky, I.A.
Salkova, E.N.
Terenetskaya, I.P.
author_sort Dyadyusha, A.G.
title Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix
title_short Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix
title_full Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix
title_fullStr Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix
title_full_unstemmed Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix
title_sort development of personal biodosimeter of uv radiation based on vitamin d photosynthesis in nematic liquid crystal matrix
publisher Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
publishDate 1999
url http://dspace.nbuv.gov.ua/handle/123456789/120261
citation_txt Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix / A.G. Dyadyusha, I.A. Gvozdovsky, E.N. Salkova, I.P. Terenetskaya // Semiconductor Physics Quantum Electronics & Optoelectronics. — 1999. — Т. 2, № 4. — С. 91-95. — Бібліогр.: 11 назв. — англ.
series Semiconductor Physics Quantum Electronics & Optoelectronics
work_keys_str_mv AT dyadyushaag developmentofpersonalbiodosimeterofuvradiationbasedonvitamindphotosynthesisinnematicliquidcrystalmatrix
AT gvozdovskyia developmentofpersonalbiodosimeterofuvradiationbasedonvitamindphotosynthesisinnematicliquidcrystalmatrix
AT salkovaen developmentofpersonalbiodosimeterofuvradiationbasedonvitamindphotosynthesisinnematicliquidcrystalmatrix
AT terenetskayaip developmentofpersonalbiodosimeterofuvradiationbasedonvitamindphotosynthesisinnematicliquidcrystalmatrix
first_indexed 2025-07-08T17:33:31Z
last_indexed 2025-07-08T17:33:31Z
_version_ 1837100970642767872
fulltext 91© 1999, Institute of Semiconductor Physics, National Academy of Sciences of Ukraine Semiconductor Physics, Quantum Electronics & Optoelectronics. 1999. V. 2, N 4. P. 91-95. PACS: 42.79.K Development of personal biodosimeter of UV radiation based on vitamin D photosynthesis in nematic liquid crystal matrix A. G. Dyadyusha, I. A. Gvozdovsky, E. N. Salkova, I. P. Terenetskaya Institute of Physics, NAS of Ukraine, 46, prospect Nauki, 03039, Kyiv-39, Ukraine, e-mail: teren@iop.kiev.ua Abstract. A new approach to the problem of personal UV biodosimeter is described. Nematic liquid crystal (LC-805) is converted into induced cholesteric phase using photosensitive chiral dopant of steroid biomolecules (7-dehydrocholesterol (provitamin D3) or 7-DHC-benzoate). Significant changes in optical characteristics of the LC films depending on the duration of UV exposure are observed as a result of UV initiated photoisomerizations that change helical twisting power of dopant molecules. Keywords: UV dosimetry, photoresponsive materials, liquid crystals, provitamin D photoisomerization. Paper received 15.10.99; revised manuscript received 15.12.99; accepted for publication 17.12.99. 1. Introduction Molecular chirality offers intriguing possibility in the de- sign of new photoactive organic materials. Conversion of nematic liquid crystals (LC) into chiral nematic (induced chol- esteric) phase using a chiral dopant, and control of the struc- ture and optical properties of LC phases by means of light play a central role in the development of molecular device and optical data storage systems. In a few cases reversible optical switching between nematic and cholesteric phase has been demonstrated [1-4]. This article discusses a possibility of applying such LC material doped with chiral biomolecule of provitamin D to dosimetry of biologically active UV radiation. It is known that solar (and artificial) UV radiation is liable for causing sunburn (erythema), premature skin aging and skin cancer. However, these acute and chronic effects only occur upon excessive UV exposures. In proper dose, UV sunlight plays an important positive biologic role initiating endogenous synthesis of vitamin D that is absolutely essential for the maintenance of healthy skeleton and bones [5]. Hence, per- sonal control of biologically active UV dose is of critical importance for human health (especially in view of stratospheric ozone depletion). The UVB portion of sunlight (280-315 nm) converts pro- vitamin D into previtamin D which, in turn, undergoes a thermally induced isomerization into vitamin D. Well stud- ied photoreaction of provitamin D in ethanol solution (model «in vitro») includes hexadiene ring-opening to form previtamin D and its further side photoconversions, the more important of which is cis-trans isomerization into tachys- terol [6]. The idea of personal UV dosimeter lies in the inser- tion of chiral molecules of provitamin D into nematic liquid crystal and close inspection of its optical properties depend- ing on the UV exposure. It is expected that the changes in helical twisting power of provitamin D molecules (as a result of UV irradiation) give rise to significant changes in optical characteristics of the cholesteric LC film. 2. Materials and methods To comply with the requirements, the LC matrix should be transparent in UV range (250-350nm), thermally stable over the interval at least 10-40 °C, be a good solvent for 7- dehydrocholesterol (and related compounds) and be stable with respect to the visible light. Nematic LC-805 (1:1 mixture of 4-n-butyl-trans-cyclohexancarbon and 4-n-hexyl-trans- cyclohexancarbon) has been selected as a host matrix [7]. It was possible to induce the cholesteric phase by doping with 5 ÷ 10 wt.% of 7-DCH or 7-DHC-Benzoate (7-DHC-Bz) as evidenced by a papillary texture observed with polarized microscope. The cholesteric mixture was filled into wedge-shaped cell (15×20 mm2) with polyimide-coated glass walls of ~ 60 µm thickness. Close inspection of the behavior of the Grandjean- Cano stripes was carried out with polarized microscope to elucidate both the sample stability (under dark conditions and visible light irradiation) and the UV effects. The UV lamp EL-30 delivered integral intensity of 0.3 mW/cm2 within A.G. Dyadyusha et al.: Development of personal biodosimeter of UV radiation... 92 SQO, 2(4), 1999 spectral range of 250-350 nm at the distance of 12 cm. In the course of UV irradiation only one half of the cell was illumi- nated, and the other half was protected with black paper. After fixed UV exposures the transmittance spectra of the both parts of the cell were recorded with KSVU-23 spectrometer in parallel with the microscope observations. In addition, the microenvironment effect on the photore- action course of 7-DHC and 7-DHC-Bz was investigated by comparison of the spectral kinetics in LC matrix with known spectral kinetics in ethanol solution. 3. Results and Discussion. Well known dependence of the number of disclination Cano stripes in wedge-shaped cell on the concentration of chiral dopant was observed with polarized microscope. It was found that the number of the Cano stripes can reach NC = 14 at best when the dopant concentration reaches 10 wt.% that corresponds to maximum solubility. The pitch of the cholesteric helix as well as helical twisting power (HTP) were determined for 7-DHC and 7-DHC-Bz using the Grandjean- Cano technique [8]. The helix is left-handed for both dopants and the HTP of 7-DHC and 7-DHC-Bz is equal in value (-1.2 µm-1wt.%-1). In unsealed cell, on keeping in dark, the Cano stripes progressively declined in number with slow broadening star- ting from the cell borders (Fig. 1). We associate this instabi- lity with the loss of twisting power of chiral dopant by oxi- dation [9]. Figure 2 demonstrates that in case of 7-DHC deg- radation of the Cano stripes proceeds more slowly than in case of 7-DCH-Bz. To avoid oxidation, on the subsequent experiments the cell was carefully sticked along the peri- meter, and the number of the Cano stripes was found to be unchanged in storage. In view of the rather low HTP of the dopants the selec- tive reflection band of the chiral LC phase is situated far enough from the visible range. Therefore effects of UV irra- diation were studied by watching the Cano stripes behavior with simulteneous registration of the cell transmittance at λ = 330 nm to find a correlation with the dopant phototrans- formations. Additionally the spectral kinetics was monitored within the spectral range 230-350 nm by sandwiched the LC mixture between two quartz plates. Comparison of the spectral ki- netics of 7-DHC and 7-DHC-Bz in ethanol and in LC-805 matrix is shown in Fig. 3. One can readily see that in both cases incorporation of the molecule in LC matrix significantly intensifies cis-trans isomerization as evidenced by the in- crease of the absorbance at 280 nm and by the spectrum transformations intrinsic to tachysterol accumulation [10]. Fig.1. Decay of the cholesteric Cano structure in unsealed wedge- shaped cell depending on the storage time observed with polarizing microscope through crossed polarizers. 0 5 10 15 20 25 30 2 3 4 5 6 7 8 9 10 7 -DHC 7 -DHC-Bz Storage time, days N um be r C an o st ri pe s Fig.2. Dependence of the number of the Cano stripes on the storage time in unsealed cells (triangles – 7-DHC in LC-805, circles – 7- DHC-Bz in LC-805). A.G. Dyadyusha et al.: Development of personal biodosimeter of UV radiation... 93SQO, 2(4), 1999 Fig.3. Spectral kinetics under irradiation with the EL-30 lamp: a) 7-DHC in ethanol, b) 7-DHC in LC matrix, c) 7-DHC-Bz in ethanol, d) 7-DHC-Bz in LC matrix. 240 260 280 300 320 340 0 0.10 0.20 0.30 0.40 0.50 0.60 a 1- 0 min 2- 6 min 3- 21 min 4 5 - - 1 1 0 6 0 0 m m i i n n 5 4 3 2 1 A bs or ba nc e Wavelength, nm 220 240 260 280 300 320 340 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 c 5 4 3 2 1 A bs or ba nc e 1- 0min 2- 4 min 3- 16 min 4 4 5 5- - - - 35 12 100 36m m m mi i i in n n n Wavelength, nm 240 260 280 300 320 3400.0 0.1 0.2 0.3 0.4 0.5 0.6 b 5 4 3 2 1A bs or ba nc e 1- 0min 2- 10min 3- 20 min 4 4 - - 35 100 m m i i n n Wavelength, nm 220 240 260 280 300 320 340 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 d A bs or ba nc e 1- 0 min 2- min 3- 7 min Wavelength, nm 1 4 5 3 1 2 5 A.G. Dyadyusha et al.: Development of personal biodosimeter of UV radiation... 94 SQO, 2(4), 1999 Besides, pronounced distinction between the 7-DHC and 7- DHC-Bz spectra in the short-wave range (around 230 nm) gives an indication of additional photoreaction channel in the case of 7-DHC-Bz. For this latter it has been found that within several hours after termination of UV irradiation the absorbance at 230 nm (both in ethanol and LC matrix) returns to its original value that suggests the thermoreversibility of this photoreaction channel. This feature can be assosiated with flexibility of benzoic fragment in relation to rigid steroid sceleton of the 7-DHC-Bz molecule [11]. The results of UV irradiation of chiral nematic phase in the wedge-shape cell are presented in Fig. 4. Close correla- tion between the changes in the Cano stripes number and the transmittance changes is easily seen for both dopants. Moreover, as the number of the Cano stripes remains fixed with the time of UV exposure, the transmittance is changed negligibly, but the every change in NC is accompanied by the sudden change in the transmittance that may be assosiated with the 2nd order phase transition. In spite of considerable quantitative difference between the 7-DHC and 7-DHC-Bz in the UV dose dependence, in both cases the three stages can be recognized in the course of UV irradia- tion. At the 1st stage the NC increase can indicate that the orientational ordering took place due to dissipation of the excitation energy after UV absorption by the dopant mol- ecules. At the 2nd stage it is likely that the dopant molecules in LC matrix are hold in the most unique position with mini- mum energy and the number of the Cano stripes is not changed with UV exposure. And at the 3rd stage the NC decrease indicates that the chiral dopants undergo photo- chemical transformations and converted into isomers pos- sessing considerably lesser HTP value as compared with the parent compounds. Of prime importance is the reversibility effect that has been found for the LC doped with 7-DHC-Bz. Despite pro- longed UV exposure resulted in total disappearance of the Cano stripes, dark storage within several hours resulted in the reappearance of the Cano texture with the original pitch value. When heated to 313 K, the restoration process was considerably accelerated, and the switching cycle was per- formed 7 times without deterioration of the LC phase. This special feature is useful for optical data storage and molecu- lar memory elements. Fig.4. Dependence of the Cano stripes number (a - 7-DHC, c – 7-DHC-Bz) and the LC cell transmittance (b – 7-DHC, d – 7-DHC-Bz) on the UV dose. 0 20 40 60 80 100 120 140 8 10 12 14 a NC Dose, J /cm 2 Dose, J /cm 2 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 2 4 6 8 10 c NC 0 20 40 60 80 100 120 140 D ose, J /cm 2 0.60 0.65 0.70 Tr an sm itt an ce b D ose, J /cm2 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Tr an sm itt an ce 1.0 0.8 0.6 0.4 0.2 A.G. Dyadyusha et al.: Development of personal biodosimeter of UV radiation... 95SQO, 2(4), 1999 Conclusions In the first time it has been experimentally found that chiral molecules of 7-DHC and 7-DCH-Bz induce stable choles- teric phases when doped in the nematic LC. Dependence of the cholesteric pitch on the irradiation UV dose has been observed that may be exploited for UV dosimetry. Acknowledgements We would like to express our gratitude to Dr. Sofia Torgova (SSC of Russian Federation «NIOPIK») for helpful advice and generous gift of LC-805, and to Dr. Wolfgang Reischl (University of Vienna) for his help with synthesis of 7-de- hydrocholesterol-Benzoate. References 1. E. Sackmann // J. Am. Chem. Soc. 93, p. 7088-7090 (1971). 2. C. Denekamp and B. L. Feringa // Adv. Mater. 10(14) pp. 1080- 1082 (1998). 3. T. Ikeda, T. Sasaki, K. Ichimura // Nature 361, pp. 428-430 (1993). 4. N. P. M. Huck, W. F. Jager, B. de Lange, B. L. Feringa // Science 273, pp. 1686-1688 (1996). 5. A. R. Webb, L. Kline, M. F. Holick // J. Clin. Endocrin.&Metab. 67, pp. 373-399 (1988). 6. I. P. Terenetskaya // SPIE Proceedings, 2134B, pp. 135-140 (1994). 7. V. G. Rumyantsev, L. M. Blinov // Optics and Spectroscopy, 47, pp. 324-326 (1979). 8. R. Hochgesand, H. J. Plach, and I. C. Sage, in: Chemicals for Optics and Electronics, pp. 2-13, EM Industries, INC., NY (1989). 9. P. W. Albro, P.Bilski, J. T. Corbett, J. L. Schroeder and C. F. Chignell // Photochem. Photobiol. 66(3), pp.316-325 (1997). 10. I. P. Terenetskaya, O. G. Perminova, and A. M. Yeremenko // J. Mol. Struct. 219, pp.359-(1990). 11. N. A. Golovina, L. I. Zagajnova, A. P. Polishchuk, G. A. Puchkovskaya, and S. I. Tatarinov // J. Appl. Spectr. 49(5), pp.833- 839 (1988).

Схожі ресурси