基于磁纳米颗粒和分子间裂分G-四链体-血红素DNA酶的Ag^+和半胱氨酸传感器研究  

Study on Biosensor for Ag^+ and Cysteine Quantification Based on Magnetic Nanoparticles and Intermolecular Split G-Quardruplex-Hemin DNAzymes

作　　者：傅昕[1] 顾丹玉 赵圣东 温世彤 张何[1] FU Xin GU Dan-Yu ZHAO Sheng-Dong WEN Shi-Tong ZHANG He(School of Chemistry and Chemical Engineering, Hunan Institute of Engineering, Xiangtan 411104, China)

机构地区：[1]湖南工程学院化学化工学院,湘潭411104

出　　处：《分析化学》2016年第10期1487-1494,共8页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金(No.21005067);湖南省自然科学基金(Nos.2015JJ2039;14JJ3133)资助~~

摘　　要：以磁纳米颗粒为固定DNA探针的固相载体,发展了一种基于分子间裂分G-四链体-血红素DNA酶的Ag^+和半胱氨酸传感器。当磁纳米颗粒表面DNA二聚体中富鸟嘌呤(G)序列与Ag^+结合时,Ag^+可有效地阻止碱基G之间Hoogsteen氢键的形成,破坏G-四链体结构。而半胱氨酸存在时,巯基与Ag^+之间相互作用,将Ag^+从碱基G上取代下来,促进G-四链体的重新形成,显示出类过氧化物酶的催化活性,催化2,2'-连氮基-双-(3-乙基苯并二氢噻挫啉-6-磺酸(ABTS)-H_2O_2反应体系的显色反应。本方法可以直接通过磁分离从样品中将检测探针与复杂体系中的干扰组分分离,有效提高了灵敏度,降低了背景信号,实现了实际样品中Ag^+和半胱氨酸的快速、灵敏、特异的比色分析。在最优条件下,Ag^+的线性检测范围为0.5~100 nmol/L,检出限为0.2 nmol/L;对半胱氨酸的线性检测范围为0.1~80 nmol/L,检出限为0.04 nmol/L。Based on intermolecular split G-quardruplex-hemin DNAzymes,a biosensor for detection of silver ions and cysteine was developed with magnetic nanoparticles（ MNPs） as carrier to immobilize the DNA probes. Since Ag^＋ chelates guanine bases at the binding sites which are involved in G-quadruplex formation,the presence of Ag^＋ may inhibit G-quartets connected by Hoogsteen-type base pairing and disrupt Gquadruplexes structures, which decreases the peroxidase activity of G-quadruplex-hemin DNAzymes that efficiently catalyze H_2O_2-mediated reactions, such as the oxidation of ABTS（ 2,2＇-azinobis（ 3-ethylbenzothiozoline）-6-sulfonic acid） by H_2O_2. Moreover,in the presence of L-cysteine,it was used as a competitor by the strongly Ag-S to release Ag^＋ from G-rich oligonucleotides,promoting the reformation of Gquadruplexes and increasing the peroxidase activity,which catalyzes the ABTS-H_2O_2 reaction system. In this experiment,the efficient separation from real sample was achieved using magnetic nanoparticles as a solid phase carrier to effectively increase the detection sensitivity and decrease the background signal. Under the optimum conditions,a high linear relationship between the UV absorbance and the Ag^＋ concentration was established in the range of 0. 5- 100 nmol / L with a detection limit of 0. 2 nmol / L. The calibration curve of cysteine was identified in the range from 0.1 to 80 nmol / L and the detection limit was as low as 0.04 nmol / L.

关 键 词：磁纳米颗粒 分子间裂分G-四链体 比色分析 AG^+ 半胱氨酸 

分 类 号：O657.3[理学—分析化学] TP212[理学—化学]