双金属协同调控G-三链体/血红素比色传感探针的构筑及应用

Construction and Application of a Bimetallic Co-regulated G-triplex/Hemin Colorimetric Sensing Probe

该文首次将一条富含G碱基的DNA序列(5’-CTGGGAGGGAGGGA-3’)与血红素结合,形成的G-三链体/血红素复合物具有类过氧化氢酶活性,能够催化H2O2的氧化反应,使反应底物2,2′-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)由无色变为绿色。通过对金属离子的筛选,发现K+和Sr2+同时存在能稳定G-三链体结构,基于此构筑了双金属协同调控的G-三链体/血红素比色传感探针,并将其用于H2O2的定量分析。在最佳实验条件下,溶液的吸光度与H2O2浓度在0.5~4.5 mmol/L范围内呈现良好的线性关系,检出限为0.07 mmol/L。将该方法用于牛奶中H2O2的检测,加标回收率为92.5%~103%,相对标准偏差为1.2%~5.4%。该探针具有碱基序列短、成本低廉、适用性强等诸多优势,为G-三链体功能化核酸探针的研究提供了新的思路。

A bimetallic co-regulated G-triplex/hemin colorimetric sensing probe for the quantitative analysis of H2O2 was constructed in this paper.Firstly,a G-rich DNA sequence(5′-CT⁃GGGAGGGAGGGA-3′)was bound to hemin,forming a G-triplex/hemin complex with peroxidaselike activity that catalyzes the oxidation of H2O2,causing the reaction substrate to change from color⁃less to green,which was used as the output module of the sensor.Then by screening the metal ions,it was found that the G-triplex structure could be stabilized in the simultaneous presence of K+and Sr2+.Under the optimal experimental conditions,the absorbance of the solution showed a good linear relationship with H2O2 in the concentration range of 0.5-4.5 mmol/L,and the limit of detection was 0.07 mmol/L.The method was used for the determination of H2O2 in milk.The spiked recoveries ranged from 92.5%to 103%,with the relative standard deviations of 1.2%-5.4%.With the advan⁃tages of short base sequence,low cost and high applicability,the probe provides a new idea for the research of G-triplex functionalized nucleic acid probes.