Our group majorly focuses on design, modification and implementation of solution and solid state NMR pulse sequences to unveil molecular interaction and dynamics relevant in the field of materials, medicine and environment to name a few.  Additionally, the group is also interested in MR methods based on solid state NQR and solution state Overhauser Dynamic Nuclear Polarization (ODNP). The group further uses various spectroscopic techniques to shed light in the cross-disciplinary areas of renewable energy sources, biomacromolecules and biomaterials. The lab is continuously expanding its research areas by collaborating with several academic and research Institutes of National repute. 

Solution state NMR methods based on relaxation and magnetization transfer allow determination of molecular correlation time and internuclear interactions. Molecular correlation time provides an idea of the motional regime accessed by the molecule that largely depends on its molecular weight. Hence, it provides a fair means to probe molecular association or aggregation in solution. Further, relaxation measurements unravel exchange of a molecule within different molecular environments highlighting conformational changes and/or complexation. NMR relaxation, diffusion and magnetization transfer based methods thus serve as indispensable tools to understand molecular interaction, association and dynamics relevant in the fields of Chemistry, Biology, Medicine, Agriculture and many other interdisciplinary areas. 

This project aims to study molecular recognition events in both biological and environmental systems by combining high-field and low-field NMR methods. At the biomolecular level, solution-state 19F NMR is applied to investigate protein–ligand binding processes using techniques such as Carr–Purcell–Meiboom–Gill (CPMG), relaxation dispersion (RD-CPMG), and saturation transfer difference (STD-NMR). The high sensitivity and wide chemical shift range of fluorine nuclei make them excellent probes for monitoring ligand binding, conformational changes, and exchange dynamics. Through these experiments, dissociation constants, number of binding sites, and exchange rates are determined, providing a detailed picture of molecular recognition at atomic resolution. Other than these studies, low-field NMR (LF-NMR) cryoporometry and relaxation analysis were employed to investigate the binding interactions of heavy toxic metal ions, such as Manganese - Mn(II), with humic acids (HAs). Paramagnetic relaxation enhancement (PRE) measurements reveal how metal ions alter water proton relaxation, offering insight into binding affinities with HAs. In addition, NMR cryoporometry is used to determine the porous architecture of humic acids, based on the melting point depression of confined liquids. These measurements are particularly relevant for understanding how humic acids interact and immobilize environmentally significant metal ions like chromium and manganese under varying pH conditions.

Analysis and quantification of ligand-protein interaction draws major attention in the field of biomedicine, agrochemicals, pharmaceuticals etc. In the recent past solution state Nuclear Magnetic Resonance (NMR) has emerged as one of the most powerful method for understanding the impact of various small to intermediate sized ligands on protein structure and function. The project aims to investigate ligand-protein interactions using solution-state multinuclear 1D Nuclear Magnetic Resonance (NMR) spectroscopy as a major technique complemented by fluorescence quenching studies, molecular docking, and Isothermal Titration Calorimetry (ITC), whenever required.  The following figures represent the graphical illustration of the objectives. Two different problems are being addressed under this umbrella. Organophosphate-protein interaction using 1H NMR and organofluorine-protein interaction employing 19F NMR methods. 

The project aims to extract humic substances following IHSS methods from various soil samples collected from different parts of western  Rajastha. Further, agrochemicals especially organic pollutants are chosen to study the interaction of HS with these molecules. Small molecule-Humic acid interactions are mainly analysed by employing multinuclear NMR methods based on relaxation, diffusion and Saturation Transfer Difference. The project further aims to design HS based biosensors for environmental pollution remediation processes. A set of sequestration experiments are designed based on electrochemical methods in collaboration with Dr. Ritu's group.   

In this project we aim to understand molecular association and/or higher order structure formation under the influence of co-solute interaction in solution. NMR relaxation at high and low field in conjunction with Dynamic Nuclear Polarization has been employed to address to problems of interest: Self association of amino acids in presence of salts and structural transition of peptides in presence of fluoroalcohols. 

As Principal Investigator:

"NMR diffusometry and relaxometry approaches to evaluate molecular interaction and dynamics in nanosponges" (Funding agency: SERB, Status: Completed)

"Ion transport dynamics in nanostructured cathode materials for Lithium and Sodium battery materials: Application of solid state MAS NMR and electrochemical methods" (Funding Agency: MoE STAR, Status: Ongoing)

"Solid State Nuclear Magnetic Resonance assessment of zinc oxide nanomaterial based drug delivery systems" (Funding Agency: SERB, Status: Completed) 

"Ligand Based 19F NMR methods with selective pulses to probe small molecule protein Interaction" (Funding Agency: IIT Jodhpur, Status: Completed)