Faculty Publications
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Item Thermal and optical characterization of biologically synthesized ZnS nanoparticles synthesized from an endophytic fungus Aspergillus flavus: A colorimetric probe in metal detection(Elsevier B.V., 2017) Uddandarao, U.; Mohan Balakrishnan, R.M.Nanostructured semiconductor materials are of great importance for several technological applications due to their optical and thermal properties. The design and fabrication of metal sulfide nanoparticles with tunable properties for advanced applications have drawn a great deal of attention in the field of nanotechnology. ZnS is a potential II–IV group material which is used in hetero-junction solar cells, light emitting diodes, optoelectronic devices, electro luminescent devices and photovoltaic cells. Due to their multiple applications, there is a need to elucidate their thermal and optical properties. In the present study, thermal and optical properties of biologically synthesized ZnS nanoparticles are determined in detail with Thermal Gravimetric Analysis (TGA), Derivative Thermogravimetric Analysis (DTG), Differential Scanning Calorimeter (DSC), Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL) and Raman spectroscopy. The results reveal that ZnS NPs exhibit a very strong quantum confinement with a significant increase in their optical band gap energy. These biologically synthesized ZnS NPs contain protein residues that can selectively bind with metal ions in aqueous solutions and can exhibit an aggregation-induced color change. This phenomenon is utilized to quantitatively measure the metal concentrations of Cu2 + and Mn2 + in this study. Further the stability of nanoparticles for the metal sensing process is accessed by UV–Vis spectrometer, zeta potential and cyclic voltammeter. The selectivity and sensitivity of ZnS NPs indicate its potential use as a sensor for metal detection in the ecosystem. © 2016 Elsevier B.V.Item Dual property of chitosan blended copolymer membranes: Antidiabetic drug release profile and antimicrobial assay(Elsevier B.V., 2020) Jaisankar, E.; Pavithra, M.E.; Krishna, S.; Thirumarimurugan, M.; Azarudeen, R.S.Membranes were fabricated from a blend of synthetic copolymer (thiourea, phenylhydrazine and formaldehyde) and chitosan to study the metformin drug release profile and its kinetics. The membranes were characterized with elemental, scanning electron microscopy, FTIR and 1H NMR spectroscopy to identify the empirical formula & weight, surface morphology and functional group changes occurred during the incorporation of chitosan to the copolymer. The swelling behaviour, drug loading efficiency and drug release profile of the membranes were studied using UV–visible spectroscopy. The mechanical properties and in vitro degradation studies were also performed. The reactive sites, better porosity and larger surface area provided by chitosan to the copolymer led to higher drug loading efficiency and controlled drug release profile. Kinetic study revealed swelling and diffusion controlled mechanism for the membranes, which obtained from Ritger-Peppas and Higuchi model. The chitosan and its copolymer membranes were tested for antimicrobial assay using selective gram-positive and gram-negative bacterial and fungal strains. The CS-TPF-drug membranes showed an acceptable control of the growth of all the microbial species compared to CS, CS-drug and the standard metformin drug. © 2019 Elsevier B.V.Item Investigation of the physicochemical factors affecting the in vitro digestion and glycemic indices of indigenous indica rice cultivars(Nature Research, 2025) Govindaraju, I.; Das, A.R.; Chakraborty, I.; Mal, S.S.; Sarmah, B.; Baruah, V.J.; Mazumder, N.Rice (Oryza sativa) is a vital food crop and staple diet for most of the world’s population. Poor dietary choices have had a significant role in the development of type-2 diabetes in the population that relies on rice and rice-starch-based foods. Hence, our study investigated the in vitro digestion and glycemic indices of certain indigenous rice cultivars and the factors influencing these indices. Cooking properties of rice cultivars were estimated. Further, biochemical investgations such as amylose content, resistant starch content were estimated using iodine-blue complex method and megazyme kit respectively. The in vitro glycemic index was estimated using GOPOD method. The rice cultivars considered in our study were classified into low-, intermediate-, and high-amylose rice varieties. The rice cultivars were subjected to physicochemical characterization by using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) techniques. FTIR spectral analysis revealed prominent bands at 3550-3200, 2927-2935, 1628-1650, 1420-1330, and 1300-1000 cm?1, which correspond to –OH groups, C=O, C=C, and C–OH stretches, and H–O–H and –CH bending vibrations, confirming the presence of starch, proteins, and lipids. Additionally, the FTIR ratio R(1047/1022) confirmed the ordered structure of the amylopectin. DSC analysis revealed variations in the gelatinization parameters, which signifies variations in the fine amylopectin structures and the degree of branching inside the starch granules. The percentage of resistant starch (RS) ranged from 0.50–2.6%. The swelling power (SP) of the rice flour ranged between 4.1 and 24.85 g/g. Furthermore, most of the rice cultivars are classified as having a high glycemic index (GI) based on the estimated in vitro GI (eGI), which varies from 73.74–90.88. The cooking properties of these materials were also investigated. Because the amylose content is one of the key factors for determining the cooking, eating, and digestibility properties of rice, we investigated the relationships between the amylose content and other biochemical characteristics of rice cultivars. The SP and GI were negatively correlated with the amylose content, whereas the RS had a positive relationship. The findings of our study can be beneficial in illustrating the nutritional profile and factors affecting the digestibility of traditional rice cultivars which will promote their consumption, cultivation, and contributes to future food security. © The Author(s) 2025.