Imidazolium based ionic liquid induced DNA gelation at remarkably low concentration

DNA dissolved in 1.0% (w/v) aqueous solution of ionic liquid (IL, 1-octyl-3-methylimidazolium chloride, [C8mim][Cl]) showed gelation transition at a remarkably low concentration of [DNA] approximate to 0.3% (w/v) unlike in hydrogels where gelation occurs >= 2.0% (w/v). Thus, the IL induced gelation was observed at 85% lower concentration. These ionogels were probed in the 0.1%-1.0% (w/v) concentration region of DNA where the hydrogels never form. The gelation temperature T-gel (and gel strength G(0), G(0) is low frequency storage modulus) increased from T-gel = 52 +/- 2 degrees C (G(0) = 10 +/- 1 Pa) to 72 +/- 2 degrees C (G(0) = 40 +/- 2 Pa) with increase in DNA content. The dynamic structure factor of gelling sol revealed ergodic to non-ergodic transition at the onset of gelation and the corresponding ergodicity breaking time tau(EB) was found to be identical to gelation time, t(gel). Interestingly, the characteristic parameters defining gelation transition, such as t(gel), tau(EB) and T-gel revealed linear dependence with DNA content. Remarkably, the gelation (also melting) temperature could be increased by as much as 2.4 degrees C when the [DNA] was raised by a mere 0.1%, which will impart considerable advantage in terms of variables, and ability to process DNA gels.