A DNA small molecular probe with increasing K + concentration promoted selectivity.

DNA small molecular probe study was considered as a promising approach to achieve DNA related disease diagnosis. Most related reports were performed under specific salinity. Herein, 4-imino-3-(pyridin-2-yl)-4 H -quinolizine-1-carbonitrile (IPQC) was generated via a facile procedure with high yield (85%). It is found that IPQC could act as a universal probe for most tested ssDNA, dsDNA and G4 DNA in low [K + ] concentration (less than 20 mM). However, IPQC showed highly selective G4 DNA binding via UV-vis and fluorescence response in increasing [K + ] ( e.g. , 150 mM) conditions. The ion atmosphere effects are instructive for DNA probe exploration. This provides guidance for the design, selection and optimization of the probes for target DNA sensing.