A universal and label-free impedimetric biosensing platform for discrimination of single nucleotide substitutions in long nucleic acid strands
A universal and label-free impedimetric biosensing platform for discrimination of single nucleotide substitutions in long nucleic acid strands
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DOI：
10.1016/j.bios.2018.02.059
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发表时间：
2018-06-30
影响因子：
12.6
通讯作者：
Chumbimuni-Torres, Karin Y.
中科院分区：
文献类型：
--
作者：
Mills, Dawn M.;Martin, Christopher P.;Chumbimuni-Torres, Karin Y.
我们报道了一种用于高选择性检测长链核酸的无标记通用生物传感平台。该传感器由一个电极固定的通用茎环（USL）探针和两个接头链，形成一个4J结构的存在下，一个特定的DNA/RNA分析物。采用K3 [Fe（CN）（6）]/K4 [Fe（CN）（6）]氧化还原电对对，对传感器进行了电化学阻抗谱（EIS）表征。电荷转移电阻（R-CT）的增加时观察到的4J结构的形成，其值取决于分析物的长度。循环伏安法（CV）被用来进一步表征的传感器和监测的电化学反应结合使用光谱椭圆偏振法获得的混合DNA单层的厚度测量。此外，使用旋转圆盘电极计算了电极/电解质界面处的电子转移。对于不同长度（22 nt、60 nt、200 nt）的核酸靶标，实现了飞摩尔范围内的检测极限。该传感器在存在单碱基错配分析物的情况下仅产生背景信号，即使浓度超过百倍。这种无标记和高选择性的生物传感平台是通用的，可用于各种长度的核酸的通用检测，这可能会彻底改变诸如细菌或癌症筛查等应用的护理点诊断。
We report a label-free universal biosensing platform for highly selective detection of long nucleic acid strands. The sensor consists of an electrode-immobilized universal stem-loop (USL) probe and two adaptor strands that form a 4J structure in the presence of a specific DNA/RNA analyte. The sensor was characterized by electrochemical impedance spectroscopy (EIS) using K-3[Fe(CN)(6)]/K-4[Fe(CN)(6)] redox couple in solution. An increase in charge transfer resistance (R-CT) was observed upon 4J structure formation, the value of which depends on the analyte length. Cyclic voltammetry (CV) was used to further characterize the sensor and monitor the electrochemical reaction in conjunction with thickness measurements of the mixed DNA monolayer obtained using spectroscopic ellipsometry. In addition, the electron transfer was calculated at the electrode/electrolyte interface using a rotating disk electrode. Limits of detection in the femtomolar range were achieved for nucleic acid targets of different lengths (22 nt, 60 nt, 200 nt). The sensor produced only a background signal in the presence of single base mismatched analytes, even in hundred times excess in concentration. This label-free and highly selective biosensing platform is versatile and can be used for universal detection of nucleic acids of varied lengths which could revolutionize point of care diagnostics for applications such as bacterial or cancer screening.