Morphological and Optoelectronic Characteristics of Double and Triple Lanthanide Ion-Doped DNA Thin Films

• Published in: ACS applied materials & interfaces Vol. 8; no. 22; pp. 14109 - 14117
• Main Authors: Kesama, Mallikarjuna Reddy, Dugasani, Sreekantha Reddy, Yoo, Sanghyun, Chopade, Prathamesh, Gnapareddy, Bramaramba, Park, Sung Ha
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08.06.2016
• Subjects: DNA lattice; DNA thin film; photoluminescence; lanthanide ion; Co-doping
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b02880

Double and triple lanthanide ion (Ln3+)-doped synthetic double crossover (DX) DNA lattices and natural salmon DNA (SDNA) thin films are fabricated by the substrate assisted growth and drop-casting methods on given substrates. We employed three combinations of double Ln3+-dopant pairs (Tb3+–Tm3+, Tb3+–Eu3+, and Tm3+–Eu3+) and a triple Ln3+-dopant pair (Tb3+–Tm3+–Eu3+) with different types of Ln3+, (i.e., Tb3+ chosen for green emission, Tm3+ for blue, and Eu3+ for red), as well as various concentrations of Ln3+ for enhancement of specific functionalities. We estimate the optimum concentration of Ln3+ ([Ln3+]O) wherein the phase transition of Ln3+-doped DX DNA lattices occurs from crystalline to amorphous. The phase change of DX DNA lattices at [Ln3+]O and a phase diagram controlled by combinations of [Ln3+] were verified by atomic force microscope measurement. We also developed a theoretical method to obtain a phase diagram by identifying a simple relationship between [Ln3+] and [Ln3+]O that in practice was found to be in agreement with experimental results. Finally, we address significance of physical characteristicscurrent for evaluating [Ln3+]O, absorption for understanding the modes of Ln3+ binding, and photoluminescence for studying energy transfer mechanismsof double and triple Ln3+-doped SDNA thin films. Current and photoluminescence in the visible region increased as the varying [Ln3+] increased up to a certain [Ln3+]O, then decreased with further increases in [Ln3+]. In contrast, the absorbance peak intensity at 260 nm showed the opposite trend, as compared with current and photoluminescence behaviors as a function of varying [Ln3+]. A DNA thin film with varying combinations of [Ln3+] might provide immense potential for the development of efficient devices or sensors with increasingly complex functionality.