核酸适配体是经过指数富集配体系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)筛选得到的能与金属离子、小分子、生物大分子,甚至整个细胞高专一性和亲和性结合的ssDNA或RNA分子。核酸适配体不仅具备抗体分子的识别特性,凡是涉及抗体的诊断领域,几乎都可以用核酸适配体来代替,而且还具备自己独特的优异性能,所以对核酸适配体的研究引起了许多科学家的关注。本文介绍了核酸适配体及其相关筛选技术(SELEX),综述了核酸适配体近年来在治疗新药、药物运输、癌细胞检测、生物成像、生物标志物的发现、毒品检测、抗病毒等生物医学领域中的应用,最后对核酸适配体在生物医学上的应用前景进行了展望。
The main purpose of this work was to develop an assay as a means of quality control in milk and dairy products. As specific and high abundant proteins in milk and diary products, casein and b-lactoglobulin were chosen as the targets, and an indirect competitive enzyme-linked immunosorbent assay(ELISA) was developed for determination of the total concentration of casein and b-lactoglobulin. The detection limit of the assay was 79.07 ng/mL,and a working range of the calibration curve was from140.6 to 36,000 ng/mL. The intra-assay and inter-assay coefficients of variations were 4.7 % and 6.5 %, respectively. The recoveries ranged from 94.1 % to 106.6 %. The developed ELISA assay was used to detect the total concentration of casein and b-lactoglobulin in liquid milk and milk powder. The results indicated that the developed assay was very specific, and the addition of nonprotein nitrogen(such as melamine, cyanuric acid, and urea) and vegetable protein did not affect the detection. The good performance of the assay makes it suitable for use in the quality control of milk and dairy products.
