基于核酸i-motif结构的pH响应荧光传感器

A Fluorescence pH Sensor Based on the Conformational Switch of i-motif DNA

利用核酸i-motif结构对质子的超敏感特性,选择富含胞嘧啶C的核酸链及其互补链,以及染料SYBR Green Ⅰ对单双链DNA的不同荧光响应特性,研制了一种灵敏的新型pH响应荧光传感器。当pH值从5.0变为7.5时,SYBR Green Ⅰ的荧光强度增大了4倍以上,pH传感范围是5.0～7.5,并显示出很高的pH分辨率(0.1个pH单元)。该pH传感器具有简单、快速、成本低等优点,有望用于相关生物过程中微小pH值变化的传感分析。

By utilizing the different response of SYBR Green Ⅰ dye to single-stranded DNA and duplex-stranded DNA,a novel fluorescence pH sensor based on i-motif DNA conformational switch has been designed.The change of the fluorescence signal and the peak position of the circular dichroism peak under different pH conditions confirmed the structural change of the nucleic acid i-motif and the change of its binding ability to SYBR Green Ⅰ dye.When the buffer solution pH changed from 5.0to 7.5,SYBR Green Ⅰ had about 4-fold fluorescence intensity enhancement.The pH resolution was 0.1pH-units.In summary,we successfully designed and demonstrated a simple,fast,and sensitive pH sensor based on the structural transformation of nucleic acid i-motif and SYBR Green Ⅰ dye characteristics.The pH sensor is simple,rapid and inexpensive.Ithasapotential to sense pH variations of certain bioprocess.