Journal Articles
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Item Probing the influence of strontium doping and annealing temperature on the structure and biocompatibility of hydroxyapatite nanorods(Royal Society of Chemistry, 2024) Patil, H.G.; Rajendran, A.; Lenka, N.; Kumar, B.S.; Murugesan, S.; Anandhan, S.Among numerous biologically important metal cations, strontium (Sr2+) has received much attention in bone tissue regeneration because of its osteoinductive properties combined with its ability to inhibit osteoclast activity. In this study, strontium-doped hydroxyapatite (Sr-HAp) nanorods with varying molar ratios of Ca : Sr (10 : 0, 9 : 1, 5 : 5, 3 : 7 and 0 : 10) were synthesized using the chemical precipitation technique. The synthesized Sr-HAp nanostructures were characterized using powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy, energy dispersive X-ray spectroscopy, and Raman and Fourier transform infrared (FTIR) spectroscopies to understand their structural and morphological features, and composition. XRD results revealed the formation of HAp nanostructures, whose unit cell volume increased as a function of the dopant level. The reaction process investigation showed the formation of hydroxyapatite (HAp), strontium apatite (SAp) and various Sr-HAp phases. FESEM micrographs displayed the morphological transformation of Sr-HAp from nanorods to nanosheets upon increasing the dopant level. In the FTIR spectra, the bands of the PO43− group shifted towards a lower wavenumber upon increasing the dopant concentration in Sr-HAp that signifies the structural distortion due to the presence of a large amount of strontium ions. The peaks of PO43− and OH− vibrations in the Raman spectra were further analysed to corroborate the structural distortion of Sr-HAp. Selected area electron diffraction patterns obtained using TEM reveal the reduced crystallinity of Sr-HAp due to Sr-doping, which is in line with the XRD results. Finally, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that the synthesized Sr-HAp has no toxic effect on the survival and growth of mesenchymal stem cells. In summary, the synthesized novel Sr-HAp nanorods exhibit great promise for bone tissue engineering applications. © 2024 The Royal Society of Chemistry.Item Copper-catalyzed aerobic annulation of hydrazones with dienones: an efficient route to pyrazole-linked hybrid molecules(Royal Society of Chemistry, 2024) Nayak, K.H.; Jijin, R.K.; Sreelekha, M.K.; Babu, B.P.A copper-catalyzed aerobic [3 + 2] annulation reaction to access various pyrazole-bound chalcones starting from readily available and cost-effective hydrazones and dienones is reported. These pyrazole-bound chalcones were further utilized effectively to prepare a series of pyrazole-linked hybrid molecules, such as pyrazole-pyrazoline, pyrazole-aziridine, and pyrazole-pyridine hybrids by efficient simple transformations. Synthetically challenging hybrid molecules were obtained in a simple, two-step process with high atom economy under aerobic copper catalysis. © 2024 The Royal Society of Chemistry.Item Base-promoted multicomponent synthesis of 1,2,4-triazole-based hybrids from 1,3-diones, β-nitrostyrenes, and hydrazones(Royal Society of Chemistry, 2024) Sreelekha, M.K.; Jijin, R.K.; Nayak, K.H.; Babu, B.P.Herein, we report a metal-free, base-promoted route for the synthesis of hybrid molecular scaffolds in which various 1,3-diones and 1,2,4-triazoles are linked by a benzyl bridge. This three-component, one-pot reaction was accomplished by first treating 4-hydroxycoumarin, trans-β-nitrostyrene, and aldehyde hydrazone in the presence of sodium carbonate. Further, this protocol was successfully expanded to other 1,3-diones, such as dimedone and 4-hydroxy-2-quinolone. A broad substrate scope, mild reaction conditions, and the metal and ligand/additive-free approach are the prominent features of this strategy. © 2024 The Royal Society of Chemistry.Item Structure-based drug design and characterization of novel pyrazine hydrazinylidene derivatives with a benzenesulfonate scaffold as noncovalent inhibitors of DprE1 tor tuberculosis treatment(Springer Nature, 2024) Naik, S.; Dinesha, P.; Udayakumar, D.In this study, we present a novel series of (E)-4-((2-(pyrazine-2-carbonyl) hydrazineylidene)methyl)phenyl benzenesulfonate (T1-T8) and 4-((E)-(((Z)-amino(pyrazin-2-yl)methylene)hydrazineylidene)methyl)phenyl benzenesulfonate (T9-T16) derivatives which exert their inhibitory effects on decaprenylphosphoryl-?-D-ribose 2'-epimerase (DprE1) through the formation of hydrogen bonds with the pivotal active site Cys387 residue. Their effectiveness against the M. tuberculosis H37Rv strain was examined and notably, three compounds (namely T4, T7, and T12) exhibited promising antitubercular activity, with a minimum inhibitory concentration (MIC) of 1.56 µg/mL. The target compounds were screened for their antibacterial activity against a range of bacterial strains, encompassing S. aureus, B. subtilis, S. mutans, E. coli, S. typhi, and K. pneumoniae. Additionally, their antifungal efficacy against A. fumigatus and A. niger also was scrutinized. Compounds T6 and T12 demonstrated significant antibacterial activity, while compound T6 exhibited substantial antifungal activity. Importantly, all of these active compounds demonstrated exceedingly low toxicity without any adverse effects on normal cells. To deepen our understanding of these compounds, we have undertaken an in silico analysis encompassing Absorption, Distribution, Metabolism, and Excretion (ADME) considerations. Furthermore, molecular docking analyses against the DprE1 enzyme was conducted and Density-Functional Theory (DFT) studies were employed to elucidate the electronic properties of the compounds, thereby enhancing our understanding of their pharmacological potential. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.Item Chromogenic Chemosensor for Simultaneous Detection of PO43? and CO32? Anions in Organo-Aqueous Solutions: Application in Arduino Based Electronic Color Sensor Device and Logic Gate(John Wiley and Sons Inc, 2024) Dhawale, A.; Trivedi, D.R.Three new chromogenic receptors have been synthesized with the primary objective of facilitating the selective recognition of PO43?and CO32? ions in an organo-aqueous medium. R1 and R2 exhibit an extraordinary detection limit aligning with both EPA and WHO guidelines. R1 shows LOD of 0.135 ppm for PO43? and 0.175 ppm for CO32?, while R2 sets forth a LOD of 0.427 ppm for PO43? and 0.729 ppm for CO32?. The binding mechanism involves intramolecular charge transfer (ICT) band are substantiated by comprehensive studies that include UV-Vis titration, 1H-NMR titration, DFT studies and electrochemical studies. Chemosensors were employed in the formulation of logic gate, the fabrication of a paper strip test kit and its application in RGB color sensor device. © 2024 Wiley-VCH GmbH.Item Rational design of an isatin-based colorimetric and solvatochromic receptor for carbonate ions and its application in molecular-scale logic gates & memory units(Elsevier B.V., 2025) Akhil Kumar, M.M.; Dhawale, A.; Trivedi, D.R.A simple and highly sensitive isatin-based colorimetric sensor ISAT 3(a-d) was synthesized through a single-step reaction. The as-prepared receptor ISAT 3b with carbonate ions (CO32? ions) shows a significant red shift in the UV–visible absorption spectra and a visible color change from pale yellow to pink. Also, the receptor ISAT 3b shows unique solvatochromic behavior with CO32? ions in different aprotic solvents and solvent compositions. Moreover, the receptor's pink coloration (absorption maxima at 544 nm) with CO32? ions could be reversible by adding HSO4? ions (attain initial pale-yellow color, absorption maxima at 425 nm), which can be repeatable. The observed color changes with spectral shift and reversibility of the receptor with CO32? ions and HSO4? ions provide “ON-OFF” switching for applying molecular logic gates. Receptors exhibited properties, such as reversibility and repeatability, benefit the design of a molecular-scale sequential memory unit with a display of “Writing-Reading-Erasing-Reading”. The real sample analysis was also carried out to prove the practical applicability of receptor (ISAT 3b) for detecting CO32? ions. © 2024 Elsevier B.V.