Thermotropic liquid crystals from biomacromolecules

Complexation of biomacromolecules (e.g., nucleic acids, proteins, or viruses) with surfactants containing flexible alkyl tails, followed by dehydration, is shown to be a simple generic method for the production of thermotropic liquid crystals. The anhydrous smectic phases that result exhibit biomacromolecular sublayers intercalated between aliphatic hydrocarbon sublayers at or near room temperature. Both this and low transition temperatures to other phases enable the study and application of thermotropic liquid crystal phase behavior without thermal degradation of the biomolecular components. Significance Liquid crystals (LCs) found in biology are usually dispersed in a solvent, typically water, and are therefore classified as lyotropic. However, from a technological perspective, thermotropic LCs (TLCs), typically based on small rod- or disc-shaped organic molecules, have been of much greater importance. In this contribution, we show that thermotropic liquid crystal phases and materials can also be made from biomolecules, demonstrating a simple generic method to form thermotropic phases from biosystems ranging from nucleic acids and proteins to even whole viruses, spanning a size from only a few nanometers to 1 μm.