Browsing by Author "Aradhana Chaudhary"

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Ameliorating enzyme functionality with temperature and pH responsive polymer interface
(Springer Science and Business Media B.V., 2025) Shailja Rai; Poorn Prakash Pande; Krishna Karthik Kumar; Aradhana Chaudhary; Tarkeshwar Prasad; Rudramani Tiwari; Km Parwati; S. Krishnamoorthi; Anupam Das
Urease enzyme activity can be related to various issues, both in biological systems and in industrial processes. A significant breakthrough in addressing the challenge to maintain enzymatic activity involves the development of enzyme-polymer based bioconjugates. This entails the utilization of dual responsive polymer matrix involving pH-responsive polymer (2-acrylamido-2-methylpropane sulfonic acid (AMPS)), neutral polymer (N, N-dimethylacrylamide (DMA)), temperature-responsive polymer (N-isopropylacrylamide (NIPAM)), and urease derivative (UD) collectively known as [PAMPS-co-PDMA-co-PUD]-b-PNIPAM (ADUN) centered on the RAFT-Grafting through polymerization process. Kinetic assessments, including a comparative study between the free enzyme and urease linked in ADUN, were conducted using berthelot reagents at different pH and temperature levels. The Lineweaver–Burk plot was used to ascertain the Michaelis–Menten kinetic constant (Km) values, which unveiled strikingly similar Km values for the free enzyme and ADUN. This indicates that urease remains active for over a month when stored at room temperature and up to around 70 °C in the case of ADUN, while it becomes dormant in the case of free urease. The microenvironment of the bioconjugates remains intact for urease in acidic pH conditions and at temperatures ranging from mild to high, when the concentration exceeds the critical micelle concentration (CMC). In general, this approach highlights the prolonged durability and commercial adaptability of ADUN for wider uses. © The Polymer Society, Taipei 2024.
Emergence of ADM-mediated bioconjugate to enhance longevity and catalytic efficiency of urease
(Elsevier B.V., 2025) Shailja Rai; Poorn Prakash Pande; Krishna Karthik Kumar; Aradhana Chaudhary; Tarkeshwar Prasad; Rudramani Tiwari; Km Parwati; S. Krishnamoorthi; Arunava Dutta
The versatile nature of the urease enzyme makes it a valuable asset in biological and industrial contexts. The creation of bioconjugates using enzyme-polymer combinations has extended the shelf life and stability of urease. A triblock copolymer, PAM-co-PDPA-co-PMAA@urease (ADM@urease), was synthesized using acrylamide (AM), 2,5-dioxopyrrolidin-1-ylacrylate (DPA), methacrylic acid (MAA), and urease via the RAFT-Grafting-To polymerization method. This polymeric interface stabilizes the enzyme and enhances substrate binding and product release, significantly boosting enzymatic efficiency. To enhance pH's influence on urease activity, three ADM grades were developed by adjusting pH-responsive MAA levels, confirmed by GPC analysis. ADM micellized at acidic pH values of 6.47 or lower, with a critical micelle concentration (CMC) of at least 0.125 mg/mL. Kinetic evaluations using Berthelot reagents at various pH levels and temperatures compared free enzyme and urease encapsulated in ADM@urease. The Michaelis-Menten constant (Km) values, derived from the Lineweaver-Burk plot, were similar for both forms. The ADM@urease demonstrated optimal stability and catalytic efficacy with a Km value of 1.18 and Vmax of 1.92 at pH 4. By improving the stability, efficiency, and performance of urease, this encapsulation technology offers potential for sustainable, eco-friendly industrial applications and advancements in biotechnology. © 2025
Fabrication of low cost thermoresponsive microgel@CuO catalyst for rapid reduction of methylene blue dye
(Springer Science and Business Media B.V., 2024) Tarkeshwar Prasad; Poorn Prakash Pande; Krishna Kumar; Shailja Rai; Aradhana Chaudhary; Anupam Das; Rudramani Tiwari; Kranthikumar Tungala; Vinai Kumar Singh
Azo dyes which are carcinogenic and mutagenic in nature are hazardous water pollutants. The present study details the catalytic reduction of methylene blue (MB) dye. In this research, the synthesis of microgels was achieved through free-radical emulsion polymerization by employing 2-hydroxyethyl methacrylate as a monomer as well as the crosslinker. The other monomers used in the synthesis of the microgels are styrene, acrylamide and N-vinylcaprolactam (NVCL). Three different grades of microgel have been synthesized by varying the amount of NVCL while keeping other monomer amounts constant. Further, copper-oxide nanoparticles have been incorporated into polymeric microgels through hydrothermal methods for catalytic reduction applications. Characterizations of both microgels and microgel-nanoparticle composites have been conducted using various techniques viz., Fourier transform infrared spectroscopy, powder X-Ray diffraction, dynamic light scattering, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The catalytic reduction of MB was studied by using ultraviolet-visible spectrophotometer. The catalytic reduction efficiency has been determined by optimizing the parameter effects of crosslinking, temperature responsive monomer feed, temperature and amount of reducing agent (NaBH4). Microgel nanocomposites have responded well in efficient catalysis at higher NVCL feed with moderate dose of NABH4. © The Polymer Society, Taipei 2024.