Research

The central focus of my research is supramolecular chemistry in the context of crystal engineering with the aim of developing functional materials that range from organic to metal-organic to inorganic materials. I have been involved in developing soft materials such as supramolecular gels (non-covalent self-assembly) for self-delivery applications.

Supramolecular Chemistry

Supramolecular chemistry is chemistry beyond the molecule. Conventional chemistry deals with covalent bonds while supramolecular chemistry examines the weaker and reversible non-covalent interactions like hydrogen bonding, hydrophobic forces, π-π interactions, electrostatic effects etc. between the molecules.

Self-assembly is a term used to describe processes in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction.

Distinctive features

thermodynamic stability – the process must lead to a lower Gibbs free energy
self-assembled structure must have a higher order than the isolated components, be it a shape or a particular task that the self-assembled entity may perform.
the key role of weak or non-covalent interactions (e.g. Van der Waals, capillary, π−π, hydrogen bonds, metal-ligand coordination) with respect to more "traditional" covalent, ionic or metallic bonds.
the building blocks are not only atoms and molecules, but span a wide range of nano- and mesoscopic structures, with different chemical compositions, shapes and functionalities. These nanoscale building blocks (NBBs) can in turn be synthesized through conventional chemical routes or by other strategies.

Crystal Engineering

What is crystal engineering and why do we need to study?

“But I am not afraid to consider the final question as to whether, ultimately – in the great future – we can arrange the atoms the way we want; the very atoms, all the way down! What would happen if we could arrange the atoms one by one the way we want them (within reason, of course; you can't put them so that they are chemically unstable, for example).” - Richard P. Feynman, 29th Dec, 1959, lecture in American Physical Society meeting.

Concept of molecule and molecular crystal

The molecule is a group of atoms held together with interactions that are so strong that it remains relatively stable under many variations in temperature and pressure.

A solid form of a substance with a definite and periodic internal structure.

an external shape made up of symmetrically arranged plane surfaces.
gives a discrete X-ray diffraction pattern.
atoms, ions or molecules are in some degree of order.
a manifestation of mutual recognition.
enthalpic factors gain over entropy.

Crystal Engineering

The understanding of intermolecular interactions in the context of crystal packing and the utilization of such understanding in the design of new solids with desired physical and chemical properties.

Supramolecular Gels for Self-delivery Applications

Smart soft materials like supramolecular gels having both biomedical and rheoreversible behavior are of great interest because they are emerging as a promising tool for injectable and as well as self-delivery vehicles delivered at the target site. These fascinating materials are able to restore both mechanical and biological properties. The main focus is to develop multi-drug based supramolecular gel for self-delivery applications. In conventional drug-delivery technique, the drug is loaded on a commercially available polymeric gel matrix which is often called a carrier molecule. In this process, efficient drug loading (physically or chemically) and releasing, functionalization of the carrier molecule with the drug, cytotoxicity, biodegradability and biostability of the carrier molecule along with side effects are some of the crucial worries associated with it whereas to overcome these major issues, an alternative drug-delivery system popularly known as ‘self-delivery’ system is being adopted. In self-delivery system, the drug/prodrug or biogenic molecule itself is converted into a supramolecular gelator either by covalent (chemically) or non-covalent (physically) interactions without using any carrier molecules. In this report, both covalent and non-covalent modifications have been employed to convert multiple drugs into supramolecular gelator as self-delivery vehicle which may be either a hydrogel for oral, invasive, and topical applications or an organogel for topical applications.

My Research Highlight

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