Thermoresponsive Chiral to Nonchiral Ordering Transformation in the Nematic Liquid-Crystal Phase of Rodlike Viruses: Turning the Survival Strategy of a Virus into Valuable Material Properties.

The current work investigates the thermoresponsive in situ chiral to nonchiral ordering transformation of a rodlike virus in the naturally assembled state-the chiral nematic liquid crystal (CLC) phase. We take this as an elegant example of reconfigurable self-assembly, through which it is possible to realize in situ transformation from one assembled state to another without disrupting the preformed assembly in general or going through a secondary assembling procedure of the disassembled building blocks. The detailed investigation presented here reveals many unique characteristics of the thermoresponsive 3D chiral ordering of rodlike viruses induced by heat stress. The chiral to nonchiral ordering transformation is highly reversible in the temperature range of up to 60 °C and can be repeated many times. There exists a critical temperature around 40 °C which is independent of the ionic strength and virus concentration. Such reconfigurable ordering in the CLC phase stems from the intrinsic structure change of constituent coat proteins without disrupting the structural integrity of the virus, as revealed by three analytical techniques targeting levels ranging from the molecular, secondary conformation of the constituent proteins to the whole single virus, respectively. Such structural flexibility, also termed polymorphism, is relative to the survival strategies of a biological organism such as the virus and can be transformed into very precious material properties. The potential of the virus-based CLC phase as the chiral matrix to regulate chiro-optical properties of gold nanorods is also presented.