Publications

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1. Krishnananda C. P, P. S Burada, Swagata Dasgupta, Ansuhree Roy, Microscopic Machinery for Ion-Triggered Drug Release from Gold Nanoparticle-Drug Conjugates, Phys. Rev. E, 111, 054405 (2025)

DOI : https://doi.org/10.1103/PhysRevE.111.054405

Study Tools 

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Surface Enhanced Raman Scattering (SERS) 

This technique uses nanostructured materials (mainly plasmonic metals) to enhance the Raman scattering of molecules. This enhancement is attributed to two main mechanisms: Electromagnetic and Chemical.

Electromagnetic enhancement arises from the localized surface plasmon resonance (LSPR) of the metal nanoparticles, which leads to an increase in the electromagnetic field around the nanoparticles. This enhanced field interacts with the molecules, amplifying their Raman scattering signals.  The order of magnitude of the enhancement factor ranges from 108 to 1011.

Chemical enhancement, on the other hand, is believed to arise from charge transfer and chemical interactions between the molecules and the metal surface. This mechanism can further enhance the Raman signals, especially for molecules that strongly interact with the metal surface. The order of magnitude of the enhancement factor ranges is 102.

SERS has been widely used in various applications, including chemical and biological sensing, environmental monitoring, and studying molecular interactions. Its high sensitivity and ability to provide detailed molecular information make it a valuable tool in research and analytical chemistry.

UV-visible (UV-vis) Spectroscopy   

UV-visible spectroscopy is a powerful analytical technique used to investigate the electronic structure of molecules. By measuring the absorption of ultraviolet (UV) and visible light, scientists can gain valuable insights into the composition and behavior of chemical compounds.

At its core, UV-visible spectroscopy relies on the principle of electronic transitions. Molecules absorb light in the UV-visible region when the energy of photons matches the energy difference between electronic energy levels. This absorption leads to the promotion of electrons from the ground state to excited states, providing a fingerprint of the molecule's structure.

Instrumentation for UV-visible spectroscopy typically includes a light source that emits UV and visible light, a monochromator to select specific wavelengths, a sample holder, and a detector to measure the intensity of transmitted light. The absorption of light by the sample is quantified, generating an absorption spectrum that reveals important information about the molecule's electronic transitions.

UV-visible spectroscopy finds wide application in various fields, including chemistry, biochemistry, environmental science, and pharmaceuticals. It is used to determine the concentration of substances in solution, study reaction kinetics, and characterize compounds. However, it is important to note that UV-visible spectroscopy is most effective for compounds with conjugated systems or chromophores, as they absorb in the UV-visible range.

In conclusion, UV-visible spectroscopy is a valuable tool in scientific research and analysis, providing a window into the electronic structure of molecules. Its versatility and sensitivity make it an indispensable technique for unraveling the mysteries of the molecular world.

Molecular Dynamics (MD) Simulations  

Molecular dynamics (MD) simulations are computational techniques used to study the behavior of atoms and molecules over time. MD simulations provide valuable insights into the dynamic properties of molecular systems by simulating the physical movements of particles based on fundamental principles of physics.

At the heart of MD simulations lies Newton's equations of motion, which describe how the positions and velocities of particles change over time in response to forces. By solving these equations numerically, researchers can simulate the movements of atoms and molecules in a virtual environment, allowing them to observe and analyze complex behaviors that would be difficult or impossible to study experimentally.

MD simulations require a detailed model of the molecular system, including information about the types of atoms, their interactions, and the environment in which they are simulated. These models can range from simple representations to highly detailed and complex structures, depending on the accuracy and detail required for the study.

MD simulations find applications in various fields, including chemistry, physics, biology, and materials science. They are used to study protein folding, drug binding, chemical reactions, and material properties, among other phenomena. MD simulations can provide valuable insights into the structure, dynamics, and function of molecules, helping researchers to understand biological processes, design new drugs, and develop new materials.