Faculty Publications
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Item Mechanistic insight into the endophytic fungus mediated synthesis of protein capped ZnO nanoparticles(Elsevier Ltd, 2019) Kadam, V.V.; JagadeeshBabu, P.E.; Mohan Balakrishnan, R.Present investigation is focused on the development of environment friendly protocol for ZnO nanoparticles synthesis using mycelial free filtrate of unexplored endophytic fungus Cochliobolus geniculatus. Zinc metal tolerant endophyte was isolated from leaves of Nothapodytes foetida and identified based on rDNA internal transcribed spacer region sequence. Surface plasmon resonance examined by UV–VIS spectroscopy analysis confirmed the synthesis of ZnO nanoparticles; exhibiting a band gap of 3.28 eV. The obtained nanoparticles were characterized by energy dispersive X-ray (EDX), high resolution transmission electron microscopy and XRD analysis. The synthesized ZnO nanoparticles were found to be polydispersed and well distributed deprived of agglomeration, crystalline, quasi spherical particles exhibiting a narrow range distribution. Fluorescence, FTIR and UV–VIS spectra depicted presence of extracellular proteins which was further confirmed by SDS-PAGE study that displayed occurrence of 52 kDa and 58 kDa protein bands involved in the synthesis of ZnO nanoparticles and further act as capping material. © 2019 Elsevier B.V.Item Photocatalytic Degradation of Caffeine Using Biogenic Silver Doped Zinc Oxide Nanoparticles(Springer Science and Business Media Deutschland GmbH, 2025) Gudadur, K.S.; Mohan Balakrishnan, R.; Kadam, V.V.This study explores the degradation of caffeine using biogenic silver-doped zinc oxide (Ag/ZnO) nanoparticles (NPs) as a heterogeneous photocatalyst. Zinc nitrate (Zn(NO3)2) and silver nitrate (AgNO3) were utilized as precursors in the biogenic synthesis of Ag/ZnO NPs. The synthesis involved incubating the mixtures for 72 h at pH 11 and a temperature of 28 °C ± 1 °C. The incorporation of silver resulted in a reduction of the bandgap energy of ZnO from 3.33 to 2.29 eV, confirming the successful synthesis of Ag/ZnO NPs. Key parameters were optimized to enhance caffeine degradation efficiency, including catalyst loading (5, 10, 15, and 20 mg), initial pollutant concentration (20, 40, 60, 80, 100, 120, and 140 ppm), hydrogen peroxide (H2O2) concentration (1, 3, 5, and 7 mM), and radiation exposure duration (20 to 200 min). The optimal conditions achieved a maximum degradation efficiency of 85.78% with a pollutant concentration of 60 ppm, catalyst loading of 15 mg/100 mL at pH 8, 5 mM H2O2 as an electron acceptor, and a radiation exposure duration of 160 min. The kinetics of caffeine degradation were found to follow a pseudo-first-order reaction. After 160 min of irradiation, the removal rates of chemical oxygen demand (COD) and total organic carbon (TOC) were 71.23% and 67.87%, respectively, indicating significant mineralization of caffeine. Additionally, the photocatalyst demonstrates impressive reusability and stability, maintaining 81.3% of its degradation capacity for caffeine even after five cycles. This highlights the excellent reusability of Ag/ZnO, making it a sustainable and environmentally friendly choice for treating industrial wastewater. Notably, the method is environmentally friendly and does not involve toxic chemicals.; To synthesize Ag@ZnO NPs using an endophytic fungal isolate from medicinal plant. Nothapodytes foetida. To study the morphological, structural, optical, and stability properties of biogenic Ag@ZnO NPs. To investigate the caffeine degradation and its underlying kinetic analysis. To characterize caffeine degradation using total organic carbon (TOC) and chemical oxygen demand (COD) analysis. © University of Tehran 2025.; © University of Tehran 2025.Item Stimulation of peroxymonosulfate using nickel ferrite nanoparticles for the degradation of Lomefloxacin hydrochloride and caffeine(Springer Science and Business Media Deutschland GmbH, 2025) Ilango, I.; Mohan Balakrishnan, R.; Visvanathan, C.; Bui, X.-T.Lomefloxacin Hydrochloride (LFH), an antibacterial agent, and caffeine (CAF), a cognitive enhancer, are excreted by humans and end up in municipal sewage effluents and surface waters. This pharmaceutical concentration in bodies of water/treatment plants poses a serious threat to both aquatic habitats and humans. A laboratory batch study on the degradation of LFH, CAF and LC (CAF and LFH mixed solution) was carried out using NFO nanoparticles to stimulate potassium peroxymonosulfate (PMS). The NFO nanoparticles were synthesized through a co-precipitation method and characterised using FTIR, XRD, FESEM/EDX, TGA/DTA/DTG, BET, AFM, VSM, and Zeta potential. The particle size distribution from FESEM (using ImageJ software) revealed that 83.3% of particles are ? 100 nm, its mean and standard deviation were estimated to be 43.87 nm and 20 to 25 nm. The NFO nanoparticles’ specific surface area was estimated to be 112.02 m2/g, and the magnetic properties of the NFO nanoparticles were investigated using VSM analysis. The parametric study included bare NFO, PMS without catalyst, pH, catalyst dosage, PMS variation with optimized catalyst, initial concentration of LFH and CAF, and reaction time, with nearly 94.34% LFH was degraded in 220 min, 100% CAF was degraded in 80 min, 78.07% LC was degraded in 40 min. The degraded compounds m/z of LFH, CAF and LC were identified using LC–MS. The recycling and regeneration of NFO nanoparticles were investigated to determine the stability of the NFO nanoparticles in the degradation of LFH and CAF in which the degradation efficiency decreased to 90.68% and 64.1% respectively upon the third wash with distilled water. As a result, the NiFe2O4/PMS system showed improved degradation even after three recycle runs, making it an efficient and economical system for degrading LFH, CAF and even to multi-pharmaceutical pollutants. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.Item Amidated pectin and gum Arabic aldehyde-based pH-sensitive hydrogel for targeted colonic treatment(Elsevier B.V., 2025) Singh, H.; JagadeeshBabu, J.; Mohan Balakrishnan, R.In this study, a novel pH-responsive hydrogel was developed by crosslinking amidated pectin(AmPec) with oxidised gum Arabic(GAA) by hydrogen and hemiacetal bonding without the need for toxic crosslinkers for oral delivery of doxorubicin to treat colon cancer. FTIR and NMR confirmed the amidation of pectin and oxidation of Gum Arabic. FTIR confirmed the formation of hydrogen and hemiacetal bonds in the hydrogel. X-ray diffraction(XRD) spectra showed the amorphous characteristic of AmPec-GAA hydrogels compared to their polymer precursors, confirming the formation of a crosslinked hydrogel. AmPec-GAA15 hydrogel swelled around 655 %±39.90 at pH 7.4 compared to 181 %±7.94 swelling at pH 1.2 after 72 h. The release of doxorubicin also followed the same trend, with only 4.48 % ±0.89 doxorubicin release at pH 1.2, while the drug release increased to 68.10 %±3.73 at pH 7.4 after 48 h. SEM micrographs revealed the macroporous and interconnected hydrogel structure with fewer pores in the hydrogel swelled in pH 1.2 compared with pH 7.4, where more visible pores were observed, indicating the pH-sensitive behaviour of the hydrogel. Hydrogel possessed excellent thermal and mechanical stability as revealed by TGA and rheology study, which can also be explored for tissue engineering applications. MTT assay on L929 cells showed cell viability above 95.1 %±,0.0074, demonstrating hydrogels' non-toxic and biocompatible behaviour. Meanwhile, Dox-loaded hydrogel induced higher cytotoxicity against HT-29 cells than free Dox in a dose-dependent manner. Therefore, the developed hydrogel can be used as an effective oral carrier to deliver doxorubicin to colon cancer while hindering its release in the stomach and thus preventing associated toxicity. © 2025 Elsevier B.V.