Electrical Conductivity of Keratin Fibers under the Action of Thioclicolic Acid
About the author:
Havrylyak V. V., Iaremkevych O. S.
Heading:
BIOLOGY
Type of article:
Scentific article
Annotation:
Introduction. Keratin fibers – widespread natural biopolymers, which are contain supramolecular nanostructures. Nowadays these materials are considered as a promising basis of modern nanotechnology. Vari- ous modifications of these fibers and their combination with other materials open up the possibilities for the creation of new biocompatible composites, which are widely used in medicine and for the production of “smart” textiles. However, little is known about the electrical properties of biopolymers and, in particular, keratins. Therefore the main purpose of this research was to examine the electrical conductance and susceptance of human hair and wool fibers under the influence of aqueous solution of thioglicolic acid by impedance spectroscopy after the action of the alternating current at a frequency from 1 Hz to 100 kHz. Materials and methods. In the experiment human hair and wool fibers with an average diameter of d = 67,3 μm and d = 28. 4 μm respectively were used. Keratin fibers were treated by 10 % aqueous solution of thioglicolic acid at 37° C during 15 min. The alternating current of varying frequency passed through the fibers and electrical conductance and susceptance were measured. For the electron microscopy keratin fibers were fixed onto a speci- men stub and then sputter-coated with copper. The fibers were inserted into JEOL JSM-Т220А Scanning Electron Microscope (Japan) operating at an accelerating voltage of 20 кV for viewing and photography. Results and discussion. It has been shown the structural changes in the surface of the human hair and wool fibers under the influence of aqueous solution of thioglicolic acid. The impact of thioglicolic acid on human hair and wool fiber was accompanied by destruction of their cuticle layer. As a result of our research it has been found a stable low-frequency conductivity of keratin fibers. The applied bioimpedance spectroscopy allowed the differentiating of conductivity on its active and reactive component. Ob- tained results indicate a sharp increase of keratin fiber’s conductance in a range from 1 Hz to 15 kHz. The maximum value of conductance was fixed at a frequency of 10 kHz. The increasing of conductance in the frequency range from 1 Hz to 15 kHz is associated with a decrease of cu- ticle layer reactance and the penetration of current into the fiber. Maximum of keratin fiber’s susceptance was observed at a frequency of 20 kHz. Moreover, the reactive conduc- tivity of chemically treated fibers at this frequency is significantly higher compared to control fibers, which indicate the rearrangement of water molecules in the amorphous areas of keratin. Keratin fibers such as wool and human hair exhibit electrical conductivity as a function of frequency. These data support the findings obtained for the stratum corneum and nail. It should be noted that both conductance and sus- ceptance dominate at low frequencies. Our results indicate that the electrical conductivity of keratin fibers greatly depends on their hydration Conclusion. Electrical conductivity of human hair and wool fibers has a similar character. For the study of the conductivity of keratin fibers the most informative is low frequency spectrum in the frequency range from 1 kHz to 70 kHz. The treatment of keratin fibers with thioglicolic acid accelerates the hydration of keratin, which leads to a change of their conductance and susceptance compared to native fibers.
Tags:
human hair, wool fiber, electrical conductance, susceptance, thioglicolic acid
Bibliography:
- AD5933 Datasheet: Analog Devices (http://www. analog. com).
- AD5933 Application Note № “Measuring Grounded Impеdance Profile Using the AD5933”, Analog Devices (http://www. ana- log. com).
- Arshakuni A. A. Nanomaterials based on Natural Protein fibers / A. A. Arshakuni, S. P. Gubin // Inorganic Materials. – 2010. – Vol. 46, № 7. – P. 734-742.
- Cheu P. Y. Biological materials: functional adaptations and bioinspired design / P. Y. Cheu, J. M. McKittrick, M. A. Meyers // Progress in Materials Sciences. – 2012. – Vol. 57. – P. 1492-1704.
- Christie J. H. A new model of DC conductivity of Hygroscopic Solids. Part II. Wool and Silk / J. H. Christie, I. M. Woodhead, S. Krenek, J. R. Seokole // Textile Research Journal. – 2002. – Vol. 72. – P. 303-308.
- Feughelman M. Mechanical properties and structure of α-keratin fibres / M. Feughelman. – Sydney : University of New South Wales Press, 1997. – 164 p.
- Hu X. Protein-based composite materials / X. Hu, P. Cebe, A. S. Weiss [et al.] // Materials today. – 2012. – Vol. 15, № 5. – P. 208-215.
- Johnson G. K. A new approach for an estimation of the equilibrium stratum corneum water content / G. K. Johnson,
- B. Yaugsness, O. G. Martinsen, S. Grimnes // Skin Research Technol. – 2010. – Vol. 16. – P. 142-145.
- Kiew K. S. Comparative study of dielectric properties of chicken feather/kenaf fiber reinforced unsaturated polyester compos- ites / K. S. Kiew, S. Hamdan, Md. R. Rahman // BioResources. – 2013. – Vol. 8 (2). – P. 1591-1603.
- Martinsen O. Dielectric properties of some keratinized tissues. Part 1: Stratum corneum and nail in situ / O. Martinsen, S. Grimnes, E. Kongshaug // Med. Biol. Eng. Comput. – 1997. – Vol. 35. -P. 172-176.
- Martinsen O, Grimnes S., Nilsen S. Water sorption and electrical properties of human nail / O. Martinsen, S. Grimnes, S. Nilsen // Skin Research and Technology. – 2008. – Vol. 14. – P. 142-146.
- Osorio F. Hair weathering. Part 1. Hair structure and pathogenesis / F. Osorio, A. Tosti // Cosmet. Dermatol. – 2011. – Vol. 24, № 11. – P. 533-538.
Publication of the article:
«Bulletin of problems biology and medicine» Issue 4 part 1 (113), 2014 year, 47-51 pages, index UDK 611. 781: 612. 014. 42