Range-tunable plasmon switching of gold nanorods by terminal breathing of surface-grafted DNA in alcoholic solvents

Abstract

Smart thermal switching of plasmonic materials holds important implications for photothermal therapy, optoelectronics, and information storage. Due to the difficulty in translation of interplays of interfacial molecular behaviors to highly controlled interparticle spacing, unfortunately, realization of a plasmon switch with rapid, sensitive, and tunable thermo-response remains challenging. We report the development of a smart plasmon switch based on gold nanorods (AuNRs) through terminal breathing of surface-grafted double-stranded (ds) DNA in alcoholic solvents. By closing dsDNA terminals on the AuNRs, DNA base pair stacking assembly of the AuNRs occurs immediately, whereas dispersed AuNRs can be restored at an elevated temperature owing to the opening of the dsDNA ends. Both electron microscopic characterizations and optical simulations confirmed that the DNA terminal breathing behavior has a significant impact on the interfacial interactions of the AuNRs and brings about repeated plasmon switching that exhibits a thermal sensitivity of 1 °C. Importantly, by altering the composition of water–alcohol mixtures, the plasmon switch can be continuously tuned with respect to temperature response range while preserving excellent switching performance. Given the high sensitivity and wide response range, the bioinspired plasmonic materials suggest expanded application scope.