Phase separation of a nematic liquid crystal in the self-assembly of lysozyme in a drying aqueous solution drop
- PDF / 887,399 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 3 Downloads / 191 Views
Research Letter
Phase separation of a nematic liquid crystal in the self-assembly of lysozyme in a drying aqueous solution drop* Anusuya Pal, Order-Disorder Phenomena Laboratory, Department of Physics, Worcester Polytechnic Institute, Worcester, MA 01609, USA Amalesh Gope, Department of English and Foreign Languages, Tezpur University, Tezpur, Assam 784028, India Rumani Kafle, Massachusetts Academy of Math and Science at WPI, Worcester, MA 01605, USA Germano S. Iannacchione, Order-Disorder Phenomena Laboratory, Department of Physics, Worcester Polytechnic Institute, Worcester, MA 01609, USA Address all correspondence to Germano S. Iannacchione at [email protected] (Received 31 October 2018; accepted 23 January 2019)
Abstract This paper discusses the unique patterns evolved through phase separation of a bulk liquid crystal (LC) from the self-assembly of lysozyme induced by evaporation of de-ionized water only. Each domain shows a central dark region surrounded by bright regions (randomly oriented LC droplets). The birefringence intensity reveals three regimes (a slow increase, rapid rise, then saturation) not seen without LC droplets. The textural study exhibits a simple exponential behavior that changes as a function of LC concentration. Furthermore, in the presence of LC, the crack patterns are found to be different near the drop edge than those in the central region.
Introduction Liquid crystals (LC) are a unique class of anisotropic materials those can explore a wide range of ordered phases. The latest experimental developments consider LC droplets as a promising tool for sensing biological and chemical events due to their label-free detection, phase-separation, and easy visualization.[1] LC-based bio-sensing systems are typically used to detect the interaction among the biomolecules by utilizing an aligned nematic state of the LC droplets.[2–7] Concurrently the interest in studying the drying drops is growing in the recent years and has attracted the attention of bio-medical and forensic applications. The drying systems include suspension of colloids, proteins (lysozyme, bovine serum albumin), LC, nanocrystals, biofluids, etc.[8–15] Apparently, the self-assembled drying mechanism of a combined system consisting of protein and LC (without any prior alignment) has not attracted any attention. This work bridges the gap between LC and drying protein droplet research by introducing a conventional, thermotropic LC at the initial concentrations of LC droplets (∅) into a lysozyme–water system. Lysozyme is often used as an archetype in studying the drying mechanism of the protein solutions. Therefore, adding bulk LC droplets in a simplest lysozyme–water system helps us to identify the effects of these droplets in the form of emerging patterns. The main findings of this paper include (1) a temporal study providing a qualitative description of the collective
* A video of the time evolution of the drying process is available in Supplementary section.
motion and the inter-particle interactions of the protein particles and t
Data Loading...
