(4dz) Unraveling Soft Matter Systems: Theoretical Insights and Molecular Simulations for Fundamental Understanding and Real-World Applications

Research Interests: Soft-matter systems have garnered significant interest within the research community due to their diverse applications in everyday life. Colloidal-scale modeling of these systems has shown growing success in various fields, including biomedical applications, electrical and thermal insulation, separation techniques using synthetic membranes, and fuel cell membranes. The study of soft matter is crucial for developing new materials and technologies that can significantly impact various industries. Currently, I am postdoctoral scholar at University of Missouri, Columbia, Missouri working with Prof. Roseanna Zia. I am studying colloidal suspensions using dynamic simulations, developing new expansions to computational models in LAMMPS. My research focuses on controlling the phase (mis)behavior of colloidal gels to produce novel materials and using patchy colloids as models to study protein gels.

Immunoglobulin gamma (IgG) antibodies are expressed as part of the body’s immune response and bind specifically to antigens. Monoclonal antibodies (mAbs) are based on IgGs, and are major platform for therapeutics, targeting diseases like rheumatoid arthritis, MS, cancer and covid. One long-standing challenge in the delivery of therapeutic mAbs is the high-concentration necessary for successful subcutaneous injection, which has a significantly lower burden of treatment for patients relative to intravenous administration and thus helps ensure medication adherence. Unfortunately, concentrated mAb solutions often have extremely high viscosities, tied directly to their physical properties – in particular, colloidal-scale attractions between individual protein molecules can drive unfavorable aggregation. Monoclonal antibody aggregation is highly undesirable as it can compromise biological functions, trigger immune responses by disrupting B-cell tolerance, and activate antibody clearance mechanisms in vivo. We utilize colloidal-scale modeling of monoclonal antibodies (mAbs) in large-scale dynamic simulations to study aggregation and predict as well as engineer the bulk rheological properties of mAb solutions. By tracking particle positions, coordination numbers, and bond dynamics, we characterize microscopic changes in the aggregating structures and correlate these changes with the resulting mesoscale structures and macroscopic properties. These predictions provide potential therapeutic strategies for directing assembled structures towards specific morphologies.

During my Ph.D. at IIT Bombay, Mumbai, I investigated the influence of intermolecular interactions and composition on the structure and phase behaviors of soft matter systems through theoretical analysis and molecular dynamics simulations. Soft matter systems present a challenge due to their involvement across a wide range of time and length scales. To address this, I employed two different levels of coarse graining for two types of soft matter systems to study their structure and phase behavior. Firstly, I focused on polymer nanocomposites, modeling the polymer as a series of connected segments where each segment comprises several monomers represented as spheres. Secondly, I examined colloidal mixtures, where the internal degrees of freedom of macromolecular particles, such as dendrimers, are averaged to yield a soft spherical particle in a binary mixture of hard and soft particles. Using the Polymer Reference Interaction Site Model (PRISM) theory and molecular dynamics simulations, I analyzed structural changes and phase transitions in soft matter systems like polymer nanocomposites and colloidal mixtures. I predicted various phase behaviors, such as depletion-driven macrophase separation, miscibility, bridging-driven macrophase separation, and chemical anisotropy-driven self-assembly, by varying parameters like interaction strengths, aspect ratios of non-interacting nanorods, and fractions of Janus nanorods. Additionally, I explored the phase behavior of size-asymmetric binary mixtures of hard and soft particles, considering different parameters like the steepness of the Generalized Exponential Model (GEM) potential, the fraction of hard particles, and the total packing fraction. These studies provide insight into the complex phase behavior and structural properties of soft matter systems.

Experience in Experimental Research: Before my Ph.D., I worked as a junior research fellow at IIT Gandhinagar, I focused on producing and stabilizing drug nanoparticles using the Precipitation by Pressure Reduction in Gas-Expanded Liquids (PPRGEL) method and the Liquid Anti-Solvent (LAS) method. In the PPRGEL method, rapid pressure reduction from 30-70 bar to 1 bar at 303 K led to high and uniform supersaturation, facilitating the precipitation of ultrafine particles. We analyzed the nucleation and growth of these nanoparticles, as well as their particle size distribution (PSD), using tools such as particle size analyzers, Zeta potential measurements, optical and SEM microscopes, and XRD analysis. Additionally, I modeled the PPRGEL method with MATLAB to study nucleation and growth kinetics. For my post-graduate dissertation, I developed a new process to stabilize multiple emulsions for drug nanoparticle production, avoiding high pressure, high temperature, and specialized equipment. Using oil droplets in W/O/W emulsions as reactors, we induced high supersaturation to precipitate and stabilize nanoparticles with surfactants. The particle size distribution was studied using an optical microscope and a BIOVIS particle size analyzer. We observed Ostwald Ripening, where larger particles grow at the expense of smaller ones and modeled this process to study particle size increase over time.

Future Research: My future research will be focused around the two aspects of soft matter study, one is fundamental research on structure and phase behavior of soft matter systems and other is application base research where colloidal-scale modeling will be used to address the challenges in drug-delivery, stability of protein-based therapeutics. I will also explore effects of various composite materials like discs, rods, and other asymmetric shapes on the properties of polymer nanocomposites and their applications in various fields.

Teaching Interests: I hold a B.Tech and M.Tech in Chemical Engineering from Dr. B.A.T. University, India, where I also served as a Lecturer for the Diploma in Chemical Engineering program for one year. During my master’s program, I had the opportunity to teach various undergraduate courses. Pursuing a Ph.D. in Chemical Engineering at IIT Bombay further honed my teaching skills, where I worked as a teaching assistant for undergraduate courses and experimental labs. With this extensive experience in both teaching and research, I am eager to teach core courses in Chemical Engineering, such as Thermodynamics, Heat Transfer Operations, Mass Transfer, and Chemical Reaction Engineering. Additionally, I am enthusiastic about designing and introducing new elective courses, including Computational Methods and Programming for Chemical Engineering, Colloids & Interfaces, and Molecular Simulations and their Applications. I am also passionate about contributing to outreach programs aimed at introducing programming and STEM research to school students. I believe that early exposure to these fields can inspire the next generation of engineers and scientists.