硫堇
适体
石墨烯
电极
检出限
电化学
分子
选择性
材料科学
线性范围
纳米技术
化学
信号(编程语言)
分析化学(期刊)
组合化学
色谱法
物理化学
生物化学
有机化学
遗传学
生物
计算机科学
催化作用
程序设计语言
作者
Feng Gao,Cai Gao,Song He,Qingxiang Wang,Anxin Wu
标识
DOI:10.1016/j.bios.2016.01.096
摘要
A label-free and highly sensitive electrochemical aptasensor for Pb(2+) was constructed using thionine (TH) as the signaling molecule and graphene (GR) as the signal-enhancing platform. The electrochemical sensing interface was fabricated by stepwise assembly of GR and TH on the lead (II) specific aptamer (LSA) modified electrode. Upon interaction with Pb(2+), the aptamer probe on the sensor underwent conformational switch from a single-stranded DNA form to the G-quadruplex structure, causing the GR with assembled TH released from the electrode surface into solution. As a result, the electrochemical signal of TH on the aptasensor was substantially reduced. Under the optimal experimental conditions, the attenuation of peak currents presented a good linear relationship with the logarithm of Pb(2+) concentrations over the range from 1.6×10(-13) to 1.6×10(-10)M. The detection limit was estimated to be 3.2×10(-14)M. The aptasensor also exhibited good regenerability, excellent selectivity, and acceptable reproducibility, indicating promising application in environment monitoring of lead.
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