In the search for biocompatible and biodegradable natural products, much attention of biomedical engineering experts is attracted by spider web (also known as spider silk). Apart from its biocompatibility and biodegradability, the key feature of spider silk is its extraordinary tensile strength, in many cases surpassing that of steel or Kevlar. Although spider silk (unlike that produced by the silk worms) cannot be produced on a mass scale, it can serve as a structural template to be imitated by the organic chemists. The main building blocks of the spider silk proteins, spidroins, are the non-polar and hydrophobic α-amino acids, and the most abundant among them are l-glycine and l-alanine. In this study, we investigated an impact of cadmium chloride (CdCl2) as a toxic anthropogenic environmental pollutant on quantitative levels of glycine, alanine, histidine, and phenylalanine in spider silk produced by the female Steatoda grossa spider kept for the periods of 4 weeks and 12 months, respectively, on cadmium-enriched diet. Quantification of this dietary effect was carried out with the aid of thin-layer chromatography, using silica gel as the stationary phase and 2-butanol- acetone-glacial acetic acid–water, 7:7:2:4 (v/v) as the mobile phase. First, the calibration curves were established for the standards of the four α-amino acids of interest (for glycine, y = 369.8x + 175.9 [r = 0.990]; for alanine, y = 725.8x + 175.3 [r = 0.985]; for histidine, y = 117.7x + 272.4 [r = 0.990]; for phenylalanine, y = 198.0x + 143.0 [r = 0.995]). Then, these four α-amino acids were quantified in the spider webs of the control spiders and those held on the cadmium- enriched diet. With all four α-amino acids of interest, their respective levels were in the range of 100 to 200 μg α-amino acid per 1 mg spider silk. The observed differences between the α-amino acid contents in the control web silk and in those produced by the cadmium fed spiders were rather insignificant and, in most cases, within the range of the experimental error. Thus, a general conclusion was drawn as to an apparent resistance of the S. grossa spider species to the environmental cadmium pollution.
R.Narayan (ed.), Biomedical Materials, Springer, New York, NY, 2009.
R.Narayan (ed.), Biomedical Materials, Springer, New York, NY, 2009.)| false