生体膜を模倣した糖鎖含有人工膜のセンサー材料への応用研究

抄録

Pathogenic bacteria Escherichia coli O-157 produce highly toxic Shiga toxins (Stx-1 and-2) which often cause fatal diseases like hemolytic uremic syndrome. The rapid detection of these bio-hazardous proteins is indispensable. This article highlights the development of Shiga-toxin sensor utilizing the quartz crystal microbalance method. Particular emphasis in this article is placed on the use of artificial alkyl globobioside (Gb2-C₁₈) and acrylamido Gb2-copolymer as carbohydrate probes, and also on the utility of the toxin sensor allowing the rapid detection within 1 hour.
The Gb2-C₁₈ probe was synthesized from per-O-acetyl-β-D-galactopyranose by a conventional chemical pathway. The alkyl Gb2 was then developed onto an air/water surface to prepare the monolayer film, which was transferred onto a quartz cell surface. Upon the addition of crude Stx-1, decrease of frequency reached saturation within 1 hour. In contrast, in the presence of the Gb2-copolymer (MW=2.5×10⁵), no frequency change was observed to show the competitive inhibition. These results show that the binding of Stx-1 is based on specific toxin-Gb2 interactions on the quartz surface. In the case of Stx-2, a largely different response resulted in the presence of the co-polymer. From the practical point of view, the present QCM system will provide a promising tool and methodology for rapid and selective detection of these Shiga toxins.