Sensitive and selective label-free DNA detection by conjugated polymer-based microarrays and intercalating dye

A series of uniquely stable oxadizole-containing conjugated polymer based microarrays and intercalating dye for a sensitive and selective label-free DNA detection were developed. Signal amplifying and self-signaling DNA microarray was prepared by means of covalent immobilization of POXI polymer on a glass substrate having isothiocyanato groups as a linker and the subsequent light-directed on-chip DNA synthesis. The binding study of intercalating dye SYBR to DNA indicate its peak broadening and bathochromic shift and aggregation and fluorescence quenching of the dye to DNA. The SYBR green concentration of 50 nM shows a 15 times signal amplification achieved from the signal amplifying DNA microarray. Selectivity tests conducted using one-mismatch DNA and random mismatch DNA demonstrate a good specificity of the DNA microarrays.