A diaminotriazine-functionalized polydiacetylene for colorimetric sensing of thymine and oligothymidine

The development of analytical methods for qualitative and quantitative detection of DNA and its core bases has attracted great attention. In this study, a diaminotriazine (DAT)-containing polydiacetylene (PDA-DAT) colorimetric sensor was developed for selective detection of thymine and oligothymidine. PDA-DAT displayed a blue-to-purple color change in the presence of thymine with a detection limit of 12.6 nM. FTIR analysis demonstrated that the color change is associated with formation of multiple hydrogen bonds between the DAT and thymine moieties in a molecular recognition process. As a consequence of the hydrogen bonding interactions, a change in the conformation of the PDA conjugated backbone takes place, causing an absorption spectral shift and corresponding color change. The PDA-DAT sensor system also selectively detects oligothymidine (40 mer) with a detection limit of 14.6 nM. The results of this study should serve as a foundation for the design of colorimetric sensors for thymine and oligothymidine.