Diffusive Dynamics of Supercooled Water, Aqueous Solution, and Water under Confinement
Although water is the most abundant liquid, it displays numerous thermodynamic and dynamic anomalies, especially accentuated in the supercooled state. While many studies have delved into the thermodynamic peculiarities of supercooled water, fewer have extensively explored its dynamic anomalies. One prominent dynamic anomaly is the violation of the Stokes–Einstein relation (SER), a crucial connection between the diffusion of particles and the viscosity of the medium. Recent advancements have enabled accurate measurements of the viscosity of supercooled water across a broad range of temperatures and pressures. This breakthrough facilitates a direct examination of SER at different temperature-pressure thermodynamic state points. Notably, there is an observed escalation in the breakdown of SER with decreasing temperature, while increased pressure mitigates this breakdown to some extent. Although existing theories offer insights into this breakdown, a comprehensive molecular mechanism was elusive. We present the translational jump-diffusion (TJD) approach that has emerged as a noteworthy development, providing a molecular-level explanation for the breakdown of SER in both pure supercooled water and aqueous solutions. The same approach has been successful in elucidating the dynamic heterogeneity observed in cell membranes. The Jump-corrected Confined Stokes-Einstein (JCSE) method, grounded in the Translational Jump-Diffusion (TJD) approach, has proven instrumental in predicting the viscosity of water within different nanochannels. This presentation seeks to highlight the TJD approach and its versatile applications in various domains.
Students Involved:
Dr. Shivam Dueby
Dr. Vikas Dubey
Mr. Golam Rosul Khan
Adaptation of Cell Membrane of Extremophiles
Extremophiles belong to a class of living species that survive and thrive in some extreme conditions of this planet, such as extreme cold, high temperature, large pressure, high salinity, etc., which are not hospitable for life. Many of these conditions induce phase transformation of the lipid membrane, a major component of the cell membrane. The lipid membrane is a two-dimensional fluid and various functions of the cell membrane necessitate an appropriate fluidity of the lipid membrane. The fluid-to-gel phase transition due to various environmental stress factors disrupts various functionalities of the cell membrane. To combat the environmental stress factors these organisms adopt several strategies to protect their cell membrane. Homeoviscous adaptation is one such strategy that prevents the fluid-to-gel phase transition of the lipid membrane by fine-tuning the lipid composition to retain the fluidity of the membrane. Another strategy to prevent fluid-to-gel phase transition is to introduce osmolytes, like urea, Trimethylamine N-oxide, sugars, etc. We focus on the mechanism of the adaptation of the lipid membrane of some extremophiles\
Publications : 33, 35, 38, 42, 47, 49, 51, 58, 63
Students Involved:
Dr. Shakkira Erimban
Ms. Archita Maiti
Ms. Nirupma Rani
The cell membrane, also known as the plasma membrane, is a dynamic structure composed of lipids, proteins, and carbohydrates. The lateral dynamics of lipids in the cell membrane play a crucial role in various cellular processes, including membrane fluidity, signal transduction, and membrane trafficking. Lipids exhibit lateral diffusion, meaning they can move sideways within the lipid bilayer. The rate of diffusion depends on factors such as temperature, lipid composition, and the presence of cholesterol. Dynamics of lipids in lipid rafts are interesting. The raft structure is also thought to result in anomalous non-Brownian-type diffusion of membrane proteins and lipids. The depiction of the spatio-temporal features of lipid raft domains is therefore key to understanding the structure-function relationship of cell membrane. While experiments using different microscopic techniques are continuously contributing to the understanding of how lipids diffuse laterally across various nanodomains (raft) in the microsecond to millisecond timescale, simulation (all atom or CG) studies does not contribute significantly except a very few reports.
Lateral Dynamics of Lipid in Cell Membrane
Publications : 52, 55
Students Involved:
Dr. Shakkira Erimban
Mr. Abhay Kumar
Interfacial Interaction and Structure of Amphiphiles on Water/Vapor Interface
The study of interfacial interaction and structure of amphiphiles at the water/vapor interface is of significant importance across various scientific disciplines, including chemistry, physics, materials science, and biology. We simulate discotic liquid crystal molecules on the water-vapor interface and study various physical properties. We also study the adsorption of aroma molecules, such as linalool, on water interface. These works are done in close collaboration with experimental groups. We predict properties, such as e surface pressure (π) - area per molecule isotherms, orientation of molecules, and their strength of hydrogen bonding. Understanding the intermolecular interactions governing self-assembly is important to engineer molecular packing that controls the charge transport in discotic liquid crystal-based organic electronics
Students Involved:
Dr. Shakkira Erimban
Mr. Tonmoy Sarma
Ms. Archita Maiti
