研究建立免标记比色法检测SNPs新法

中科院长春应用化学研究所电分析化学国家重点实验室董绍俊院士(TWAS)课题组在基于血红素-石墨烯纳米复合物免标记比色法检测单核苷酸多态性研究方面取得重要进展，相关成果发表在美国化学会期刊《ACS纳米》 ACS Nano  （2011,5,1282-1290）上。

石墨烯是碳原子紧密堆积成单层二维蜂窝状晶格结构的一种碳质新材料，由于其具有表面积大、热性能和导电率高、机械强度大、生产成本低等特点和独特的纳米结构，可广泛应用于在纳米电子学、纳米光子学、传感器和纳米复合材料等领域，已成为国际研发的热点。

该课题组利用化学法，通过血红素与石墨烯之间π-π相互作用合成了血红素功能化的石墨烯纳米杂化材料(H-GNs)。这种新的纳米材料在水溶液中具 有很好的稳定性，并且具有血红素和石墨烯的优良性质。石墨烯表面上附着的血红素使得H-GNs具有过氧化氢酶的性质，能够催化过氧化氢氧化过氧化氢酶底物 的反应；H-GNs在水溶液中的分散符合2D的Schulze-Hardy规则，当电解质的浓度超过临界聚沉浓度(ccc)后，H-GNs溶液就会由于电 荷屏蔽效应发生聚集；单链DNA（ss-DNA）和双链DNA（ds-DNA）与H-GNs之间的亲和力不同，可以在最佳盐浓度下利用H-GNs的不同聚 集状态区分ss-DNA和ds-DNA。

基于H-GNs的这些特点，研究人员建立了一种免标记比色法检测乙肝病毒(HBV)的单碱基多态性(SNPs)的方法。该方法简便、快速、经济效益高，而且无需DNA底物进行标记。更重要的是，该方法可以在室温下利用肉眼直接观察，这使得它比利用复杂的仪器更方便。

由于其操作简便，特异性好，该方法在包含单碱基突变等遗传性疾病的临床诊断中具有潜在的应用价值，可能为病原学诊断和遗传性疾病带来希望。（生物谷Bioon.com）

生物谷推荐原文出处：

ACS Nano, 2011, 5 (2), pp 1282–1290，DOI: 10.1021/nn1029586

Hemin-Graphene Hybrid Nanosheets with Intrinsic Peroxidase-like Activity for Label-free Colorimetric Detection of Single-Nucleotide Polymorphism

Yujing Guo, Liu Deng, Jing Li, Shaojun Guo, Erkang Wang, and Shaojun Dong

This paper demonstrated for the first time a simple wet-chemical strategy for synthesizing hemin?graphene hybrid nanosheets (H-GNs) through the π?π interactions. Significantly, this new material possesses the advantages of both hemin and graphene and exhibits three interesting properties. First, H-GNs have intrinsic peroxidase-like activity, which can catalyze the reaction of peroxidase substrate, due to the existence of hemin on the graphene surface. Second, their dispersion follow the 2D Schulze?Hardy rule, that is to say, the coagulation of H-GNs in electrolyte solution results from the interplay between van der Waals attraction and electric double-layer repulsion. Third, H-GNs exhibit the ability to differentiate ss- and ds-DNA in optimum electrolyte concentration, owing to the different affinities of ss- and ds-DNA to the H-GNs. On the basis of these unique properties of the as-prepared H-GNs, we have developed a label-free colorimetric detection system for single-nucleotide polymorphisms (SNPs) in disease-associated DNA. To our knowledge, this is the first report concerning on SNPs detection using functionalized graphene nanosheets. Owing to its easy operation and high specificity, it was expected that the proposed procedure might hold great promise in the pathogenic diagnosis and genetic diseases.

Keywords (keywords): graphene nanosheet; hemin; single-nucleotide polymorphism; artificial enzyme mimetic