Cholesteric liquid-crystalline DNA - a new type of chemical detector of ionizing radiation

Liquid crystals (LCs) can be promising for detection of ionising radiation (IR). However, there is little information about their interaction with IR and there are no systemic studies of the dosimetric application of LCs. In this communication, we show for the first time the capabilities of a new type of radiation detector - cholesteric liquid-crystalline dispersion (CLCD) of DNA obtained using polyethylene glycol (PEG) and salt indued condensation. Irradiation of the DNA CLCD samples with 0-100 kGy of 7.6 MeV bremsstrahlung led to significant change in their circular dichroism (CD): approximate to 5% and approximate to 12% increase in the signal was observed at 10 and 20 kGy, while in the range of 20-90 kGy the CD signal decreased linearly. Thus, detectors based on DNA CLCD could be of interest for such application of IR as material modification or radiation sterilisation. At the same time irradiation can help to stabilise dispersion particles and can be used to prevent their sedimentation. Unirradiated samples degraded within 24 h after preparation, while the irradiated ones were able to maintain the intensity of CD signal for more than 168 h.Schematic representation of the dual effect of radiation exposure the DNA CLCD.