| dc.description.abstract | Molecular self-assembly is ubiquitous in nature and plays a vital role in the emergence and maintenance of life. For example, DNA strands self-assemble into a double helix that stores genetic information. Likewise, organization of various proteins into multiprotein complexes enable transcription and numerous other cellular processes rely on precise self-assembly of different components. The great complexities and multiple functionalities observed in natural systems have inspired scientists to mimic such dynamic systems utilizing supramolecular strategies. Supramolecular self-assembly is the process of organization of individual units into highly arranged/ordered structures/patterns with the help of non-covalent interactions and has emerged as one of the most powerful strategies to mimic biomolecular self-assemblies. One of the most interesting features of living system is its adaptive functionality such as tunable catalytic activity in response to variety of signals. Such adaptive features involve competing transient activation and deactivation processes, which are governed by enzyme-mediated energy input and consumption, and molecular interactions. While there is a growing interest in mimicking these dissipative self-assembly behaviors in synthetic systems, the development of functional dissipative materials is still in infancy.
In the pursuit of creating biomimetic functional and adaptive artificial systems, we have developed novel dynamic assemblies that display multi-functional properties. The central focus of the thesis revolves around the development of different supramolecular frameworks incorporating imidazole derivatives and metal ions with the capability to adapt, respond to various stimuli, and exhibit emergent properties essential for both biological and environmentally sustainable applications. To begin with, we have designed a metal ligand interaction-driven supramolecular strategy to generate a vesicular enzyme mimetic, known as nanozyme, which exhibits multi-enzymatic activity and high stability in harsh conditions. Notably, the developed nanozymes can dynamically tune their catalytic activity in response to external stimulus such as pH, providing robust platforms resembling dynamic natural systems. Subsequently, the developed supramolecular nanozyme was used for the detection of hydroxyurea drug, which is the first FDA approved drug for the treatment of sickle cell anaemia.3 Furthermore, the nanozyme was utilized as a catalyst for the generation of nitric oxide from endogenous nitrosylated prodrugs. To further introduce complexity and dual catalysis into the vesicular system, we have constructed a three-component assembled framework comprising of a copper center, a tetradentate chelator, and a synthesized ligand containing imidazole headgroups. These vesicular assemblies exhibit dissipative behavior and catalyzes both aqueous and non-aqueous reactions, reminiscent of the compartmentalized biochemical reactions observed in biological systems. Biomolecular assemblies’ function by the dissipative self-organization of molecules, which is regulated by a series of chemical reactions. Toward achieving the transient assemblies, we utilized kinetic asymmetry of Cu(II) chelation that creates a non-equilibrium steady state. Our work suggests new avenues for metal ion-mediated dynamic supramolecular systems, opening up a massive gamut of functionally dynamic life-like assemblies. Besides, we have designed a porous coordination polymer utilizing non-fluorinated ligands to impart superhydrophobic properties. This material offers robustness against abrasion and harsh conditions and finds practical applications including efficient oil-water separation, prevention of ice formation on surfaces, and self-cleaning. We envisage that our approaches will significantly expand the repertoire of biomimetic supramolecular systems, enabling precise control of molecular self-assembly and associated functionality. | en_US |
