8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P4.24Fri 911:10-14:00Initial steps of DDCA (didecyldimethylammoniumchloride) modified DNA rehydration by 1H-NMR andsorption isothermJan Kobierski, 1 Hubert Haranczyk, 1 Dorota Zalitacz, 2 Monika Marzec, 1 and JacekNiziol 21 Jagiellonian University, Institute of Physics, ul. Reymonta 4, 30-059, Kraków,Poland2 AGH University of Science and Technology, Faculty of Physics and Applied ComputerScience, Kraków, PolandNatural DNA [1] is exclusively water soluble, what makes it useless for real world electronicsand photonics. A breakthrough in DNA-based technology was made by demonstrating a series ofDNA-cationic surfactant complexes [2]. Those complexes are insoluble in water but become solublein alcohols and other common solvents. They have been applied to organic photovoltaics, andorganic field effect transistors [3]. In view of future application water pick-up by DNA-complexesshould be well understood and controlled. We measured a number and a distribution of water bindingsites, sequence and kinetics of their saturation, and the formation of tightly and loosely boundwater fractions at the initial steps of rehydration process for salmon sperm DNA modified by theprior use of didecyldimethylammonium chloride (DDCA). The hydration courses were performedfrom the gaseous phase with the controlled humidity, at room temperature, over the surfaces ofsaturated solutions. The hydration kinetics reveals a very tightly bound water not removed by prolongedincubation at, a tightly bound water, and a loosely bound water fraction. Swelling processwas observed at the hydration p/p0 = 100%. The sorption isotherm was constructed using the saturationhydration values obtained from the hydration courses. Proton free induction decays (FIDs)were recorded on 30MHz relaxometer. The measurements were performed at room temperature.Proton FID is a superposition of the immobilized proton signal fitted by Gaussian function comingfrom the solid matrix of DNA and two liquid signal components coming from tightly bound, andloosely bound water fraction. [1] H. Harańczyk, J. Czak, P. Nowak, J. Nizio, Acta Phys. Polon.A117, 257-262 (2010). [2] L. L. Wang, J. Yoshida, N. Ogata, Chemistry of Materials 13, 1273(2001). [3] C. Yumusak, T. B. Singh, N. S. Sariciftci, J. G. Grote, Appl. Phys. Lett. 95, 263304(2009).24