Selective recognition of G–G mismatch using the double functional probe with electrochemical activeferrocenyl

A new electrochemical assaying approach with label-free to identify GG mismatch in DNA duplexes was developed by applying a new double functional probe (FecNC), ferrocenyl modified naphthyridine derivative, which contain recognition domain (naphthyridine derivative) and electroactive center (ferrocenyl group). The double functional probe exhibited not only the excellent electrochemical response devoted from ferrocenyl but also high selective electrochemical signal “off” for G–G mismatch duplex. The interaction was also verified by melting temperature and circular dichroismic spectra (CD). The electrochemical investigation showed that the redox of FecNC was a diffusion-controlled process and the diffusion coefficient of bound-FecNC was much smaller than free FecNC. The correlation between the current of FecNC and concentration of GG mismatch duplex indicated that the bind saturation point was about at a 1:1 mole ratio. The novel double functional electrochemical probe might provide a versatile and low-cost way to detect single nucleotide polymorphisms, which could be found extensive applications in the diagnosis of the genetic diseases.

► Double functional probe (FecNC) containing recognition and electrochemical activity domains was achieved by conjugated ferrocenyl with naphthyridine derivatives. ► Through the designed double functional probe (FecNC), a novel label-free electrochemical approach was developed for high selective recognition of GG mismatch. ► Presence of ct-DNA did not interfere with recognition ability of FecNC for GG mismatch, which contributed to real SNP detection. ► Label-free electrochemical approach has very simple experimental operation only with a naked Au electrode, without immobilizing and introducing additional reporter molecule.