Biology subjects

Saha-Dasgupta, T.

Publications and source records attributed to Saha-Dasgupta, T..

4 recordsLinked to original sources

bioRxiv2021

A Combined Spectroscopic and Molecular Modeling Study on Structure-Function-Dynamics under Chemical Modification: Alpha-Chymotrypsin with Formalin Preservative

Enzyme conformations can be altered via modification of its amino acid residues, side chains and large-scale domain modifications, which are closely linked to its function. Herein, we have addressed the role of residue modification in catalytic activity and molecular recognition of an enzyme alpha-chymotrypsin (CHT) in presence of covalent cross-linker formalin. Optical spectroscopy studies exhibit reduced catalytic activity of the enzyme with increased formalin concentration. Polarization gated anisotropy studies of a fluorophore 8-anilino-1- napthelenesulfonic acid (ANS) in CHT show a dip rise pattern in presence of formalin which is consistent with the generation of multiple ANS binding sites in the enzyme owing to modifications of its local amino acid residues. Molecular docking study on minimal local residue modifications in CHT reveals formation of a stable enzyme-substrate complex even with the serine-histidine cross-linked enzyme which prohibits product formation giving rise to reduced catalytic activity.

biophysics↗

bioRxiv2021

Development of Tribo-Electroceutical Fabrics for Potential Application in Self-sanitizing Personal Protective Equipment (PPE)

Attachment of microbial bodies including coronavirus on the surface of personal protective equipment (PPE) is found to be potential threat of spreading infection. Here, we report the development of a novel tribo-electroceutical fabric (TECF) consisting of commonly available materials namely Nylon, and Silicone Rubber (SR) for the fabrication of protective gloves on Nitrile platform, as a model wearable PPE. A small triboelectric device (2 cm x 2 cm) consisting of SR and Nylon on Nitrile can generate more than 20 volt transient or 41 {micro}W output power, which is capable of charging a capacitor up to 65 V in only [~]50 sec. The novelty of the present work relies on the TECF led anti-microbial activity through the generation of an electric current in saline water. The fabrication of TECF based functional prototype gloves can generate hypochlorite ions through the formation of electrolysed water upon rubbing them with saline water. Further a computational modelling has been employed to reveal the optimum structure and mechanistic pathway of anti-microbial hypochlorite generation. Detailed anti-microbial assays have been performed to establish effectiveness of such TECF based gloves to reduce the risk from life threatening pathogen spreading. The present work provides the rationale to consider the studied TECF, or other material with comparable properties, as material of choice for the development of self-sanitizing PPE in the fight against microbial infections including COVID-19.

microbiology↗

bioRxiv2021

Nanoceutical Fabric Prevents COVID-19 Spread through Expelled Respiratory Droplets: A Combined Computational, Spectroscopic and Anti-microbial Study

Centers for Disease Control and Prevention (CDC) warns the use of one-way valves or vents in free masks for potential threat of spreading COVID-19 through expelled respiratory droplets. Here, we have developed a nanoceutical cotton fabric duly sensitized with non-toxic zinc oxide nanomaterial for potential use as membrane filter in the one way valve for the ease of breathing without the threat of COVID-19 spreading. A detailed computational study revealed that zinc oxide nanoflowers (ZnO NF) with almost two-dimensional petals trap SARS-CoV-2 spike proteins, responsible to attach to ACE-2 receptors in human lung epithelial cells. The study also confirm significant denaturation of the spike proteins on the ZnO surface, revealing removal of virus upon efficient trapping. Following the computational study, we have synthesized ZnO NF on cotton matrix using hydrothermal assisted strategy. Electron microscopic, steady-state and picosecond resolved spectroscopic studies confirm attachment of ZnO NF to the cotton (i.e., cellulose) matrix at atomic level to develop the nanoceutical fabric. A detailed antimicrobial assay using Pseudomonas aeruginosa bacteria (model SARS-CoV-2 mimic) reveals excellent anti-microbial efficiency of the developed nanoceutical fabric. To our understanding the novel nanoceutical fabric used in one-way valve of a face mask would be the choice to assure breathing comfort along with source control of COVID-19 infection. The developed nanosensitized cloth can also be used as antibacterial/anti CoV-2 washable dress material in general. GRAPHICAL ABSTRACT O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY A novel nanoceutical cotton fabric duly sensitized with non-toxic zinc oxide nanoflower can potentially be used as membrane filter in the one way valve of face mask to assure breathing comfort along with source control of COVID-19 infection. The nanoceutical fabric denatures the SARS-CoV-2 spike protein and makes the microorganism ineffective.

microbiology↗

bioRxiv2020

Incorporation of a Biocompatible Nanozyme in Cellular Antioxidant Enzyme Cascade Reverses Huntington's Like Disorder in Preclinical Model

The potentiality of nano-enzymes in therapeutic use has directed contemporary research to develop a substitute for natural enzymes, which are suffering from several disadvantages including low stability, high cost, and difficulty in storage. However, inherent toxicity, inefficiency in the physiological milieu, and incompatibility to function in cellular enzyme networks limit the therapeutic use of nanozymes in living systems. Here, we have shown that citrate functionalized manganese-based biocompatible nanoscale material (C-Mn3O4 NP) efficiently mimics glutathione peroxidase enzyme in the physiological milieu and easily incorporates into the cellular multienzyme cascade for H2O2 scavenging. A detailed computational study reveals the mechanism of the nanozyme action. We further established the in vivo therapeutic efficacy of C-Mn3O4 nanozyme in a preclinical animal model of Huntingtons disease, a prevalent progressive neurodegenerative disorder, which has no effective medication till date. SUMMARYAlthough, nano-enzymes have shown lots of promises in the management of several diseases, two major concerns limit their clinical translation. Apart from the inherent toxicity of the constituent materials (e.g., cerium, vanadium, gold, etc.), activities of contemporary nanozymes are often inhibited in physiological milieu. Furthermore, most of them are incapable of incorporation into the cellular metabolic networks for functioning in tandem and parallel with natural enzymes, a major criteria for potential therapeutics. Here, we have shown that citrate-functionalized spherical Mn3O4 nanoparticles can efficiently mimic glutathione peroxidase (GPX) enzyme without the limitations of contemporary nanozymes, and effectively manage neurodegenerative Huntingtons disease in preclinical animal model. The choice of the material in the nanozyme lies on the fact that Mn is an essential micronutrient for mammals, and the stabilizing ligand citrate helps the nanoparticles to cross the blood-brain-barrier to reach brain. We have shown that the nanozyme can easily be incorporated in cellular antioxidant enzyme cascade. The specificity and efficacy of the nanozyme in the cascade was significantly higher compared to other reported nanozymes. We have justified our experimental findings with a detailed computational study. Understanding the mode of operation and management of Huntingtons disease in preclinical animal trial using a biocompatible (non-toxic) nanozyme as a part of the metabolic network may uncover a new paradigm in nanozyme based therapeutic strategy.

pharmacology and toxicology↗