基于纳米金簇过氧化物模拟酶活性调控的分析方法构建

The nanomaterials based enzyme mimics have been attracted great attentions owing to their superior resistance against activity losing and lower cost during their storage and applications. Up to now, many of nanomatrials were certified to be peroxidase mimtetics and were just used for restricted analysis. Herein, we proposed a new strategy based on tuning the peroxidase mimetics activities of bovine serum albumin (BSA) protected gold nanocluster (BSA-Au NCs)to develop new annlytical methods. Owing to that little enzyme mimics can catalyze chromogenic reactions of plenty of chromogenic substrates, slight changes bringing varations to the enzyme mimincs activities can be sensitively expressed through the apparent color changes. And the selectivity of our method is high for the specific tuning of activity of peroxidase-like activity by analytes. With varying the recognising reagents modified onto the surface of BSA-Au NCs, various substances can be sensitively detected through this strategy. Analytical methods developed here can achieve very high sensitivity and selectivity. These will not only help to extend applications of the nanomaterials based enzyme mimetics in analytical chemistry, but also show potential to improve sensitivity and selectivity of detection.

纳米模拟酶因克服了天然酶易失活、难储存、成本高等缺点而成为研究热点。多种纳米过氧化物模拟酶已应用于分析检测；但检测对象还很有限。本项目拟构建“基于纳米金簇过氧化物模拟酶活性调控的分析方法”：以BSA-纳米金簇为纳米过氧化物模拟酶的代表，研究纳米金簇模拟酶活性调控机制；基于待测物质对BSA-纳米金簇模拟酶活性的选择性调控，结合显色反应实现对多种待测物的选择性检测。由于少量酶可以催化大量显色底物的反应，酶活性的微小变化会导致信号发生很大的变化，因此这种“基于模拟酶活性调控的分析方法”具有很高的灵敏度；利用待测物质与纳米金簇特异性作用所引起的模拟酶活性变化，该方法具有很好的选择性；通过在纳米金簇表面修饰不同识别物质，可以实现对不同物质的检测。这种新的分析策略不仅能拓宽纳米模拟酶在分析化学中的应用范围，还能提高检测的灵敏度和选择性。

辣根过氧化物酶（HRP）是分析化学中最常用的酶。但作为天然酶，HRP易失活、价格贵。因此，有必要开发HRP的模拟酶。我们发现，蛋白酶（无花果酶、木瓜酶）和荧光素衍生物具有类似过氧化物酶的活性，可以催化H2O2氧化多种底物发生显色反应。基于蛋白酶的过氧化物模拟酶活性，我们构建了检测H2O2、谷胱甘肽的新方法；结合葡萄糖氧化酶、尿酸氧化酶，构建了检测葡萄糖、尿酸的新方法；以多巴胺为底物，构建了检测多巴胺的方法；通过和血红素的结合，提高了无花果酶的过氧化物模拟酶活性。我们系统研究了荧光素模拟酶活性与结构的关系，发现羧基的引入可以提高活性，而氨基的引入则降低活性；结合葡萄糖氧化酶和半乳糖氧化酶，分别构建了检测葡萄糖和半乳糖的新方法。与HRP相比，蛋白酶和荧光素衍生物不易失活、价格低廉；与纳米模拟酶相比，蛋白酶和荧光素衍生物无需合成。同时，蛋白酶和荧光素衍生物用于分析测定的灵敏度与HRP、纳米模拟酶相当。我们的结果证实，一种酶可能具有多种催化活性，为深入理解酶的活性奠定了基础；也证实了小分子模拟酶活性与基团的关系，为设计新的模拟酶奠定了基础。