ABSTRACT

Modern technological breakthroughs have facilitated the emergence of exciting new research in the science of materials, and the development and synthesis of new forms of material with unique new attributes that can be adapted to all manner of purposes. One of the most interesting subfields within this domain is that of ‘biomimetic materials’, which are essentially developed using nature and its structures as their model. Researchers in this area work to synthesize substances that can imitate the properties and functions of matter in the organic and natural world. This research has led to breakthroughs such as artificial muscles that may be used for medical purposes, or in biotechnology/robotics, and biomimetic enzymes that have found applications everywhere: from biosensing and immunoassays, to stem cell growth and the removal of pollutants.
Attempting to make new headway within this exciting domain is a new research projected led by Professor Dharmesh Varade of Ahmedabad University’s School of Engineering and Applied Science. Having received a three year grant worth around Rs. 38 lakh as part of the Science and Engineering Research Board’s Early Career Research Grant scheme, the project was initiated in early 2017 and currently has on board the School’s Professor Ajay Karakoti as a Research Partner, and Manyala Dhana Laxmi as a Junior Research Fellow. The basic objective of the project is to develop a new form of super-stable, responsive aqueous foam that has the potential for being utilised in the synthesis of novel biomimetic materials.
The project attempts to work on a simple and sustainable system that combines a good foamability and an outstanding foam stability, which can then be readily tuned to weak foam stability by changing the polymorphism of the system upon heating. To achieve this, catanionic surfactant systems, i.e. mixtures of cationic and anionic surfactants will be utilized. Such mixtures are expected to show viable properties with respect to foam formation and stabilization as they are well-known to pack very competently at the gas/water interface. This affords free surfactant in the solution and forms vesicles usually considered at thermodynamic equilibrium. The existence of vesicles will afford bulk viscoelastic properties and provides good foam stability once generated, as they work towards efficiently blocking liquid drainage.
Here, the foamability and the outstanding foam stability of that system at room temperature will be studied in an attempt to establish a link to the supramolecular assembly (vesicles) in water. Moreover, this stable foam can be used as a template for the synthesis of novel biomimetic materials. Here’s how: In solution, those vesicles may melt into micelles at a temperature depending on the nature of the surfactants. Hence, this can allows us to tune the foam stability with temperature. The stabilizing surfactant aggregates adsorbed at the gas/liquid interface is quite analogous with the extended form of Langmuir monolayers. These monolayers, arranged parallel to each other and separated by Plateau border, offer a greater possibility for the binding various charged ions at the gas–liquid interface, thereby, utilizing the liquid lamellae as a plausible template for growing a wide variety of biomimetic materials like metal and alloy nanoparticles (Au, Pt, Ag, Pd, Ni, Co etc.), metal oxide (CeO2) and metal oxide on metal (MOM) nanoparticles (CeO2@Au).
The project aims to study the enzymatic activity of bimetallic nanoparticles and compare the reactivity with individual nanoparticles prepared via the aqueous foam method. In addition, the goal is also to study the enzymatic activity of metal oxide on metal system using CeO2@Au as the model system as it will combine the peroxidase activity of gold with superoxide dismutase (SOD) activity of cerium oxide nanoparticles. This system, if successful, will be unique as we will be able to demonstrate and create an inorganic nanoparticle system that can show dual enzymatic activity in a single system.
  

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