• NISHA J THARAYIL

Articles written in Bulletin of Materials Science

• DNA-assisted synthesis of chitosan/$\alpha$-Fe$_2$O$_3$ nanocomposites for antioxidant and antimicrobial activities

Novel nanocomposites, based on chitosan/α-Fe$_2$O$_3$ (C/FD), have been successfully synthesized. The FDnanoparticles were prepared by co-precipitation method using DNA as the capping agent. The samples were characterizedby XRD, EDAX, SEM and TEM. The hematite nanoparticles that were prepared using DNA were compared withthe samples prepared using EDTA and CTAB as capping agents. The effect of C/FD nanocomposites on the growth offew common water pathogens were studied to explore its use as an antibacterial agent to be used in water purification.The antioxidant activity of samples was tested using a DPPH assay at two different concentrations of FD. It provides thepossibility of improving radical scavenging activity by varying the preparation conditions. The results also showed that theC/FD being a bio-compatible, eco-friendly and low cost material is used to inhibit the growth of several fungi and bacteriathat can be useful for a number of applications in the food and pharmaceutical industry.

• DNA-assisted synthesis of nanoceria, its size dependent structural and optical properties for optoelectronic applications

Cerium oxide (CeO$_{2−x}$) nanoparticles or nanoceria were synthesized by the chemical co-precipitation method using cerium nitrate hexahydrate and ammonium carbonate as starting materials and deoxyribonucleic acid (DNA) as acapping agent. The structural and optical characterization of the prepared nanoparticles was studied in depth by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy, Raman spectroscopy, UV–visible absorption and diffuse reflectance spectroscopy. The average crystallite size and latticeparameters of the cerium oxide nanoparticles at different calcination temperatures were studied using XRD analysis. The average crystallite size was found to be 6 nm and the size increases with calcination temperature. The polycrystalline nature and the size of the particles obtained are in close agreement with HRTEM and Raman analysis. The optical band gaps ofall samples were measured by Tauc plot which showed a blue shift with a decrease in size due to the quantum confinement effect. The optical absorption spectrum of the synthesized nanoparticles showed the absorption of UVA, UVB and UVC light, and the variation in structural and optical properties with size makes them suitable for the optoelectronic application. To the best of our knowledge, this is the first report on using DNA in the synthesis of nanostructured ceria.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020