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Manganese‐Based Nanozymes: Multienzyme Redox Activity and Effect on the Nitric Oxide Produced by Endothelial Nitric Oxide Synthase
Author(s) -
Singh Namrata,
Geethika Motika,
Eswarappa Sandeep M.,
Mugesh Govindasamy
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201800770
Subject(s) - nitric oxide , umbilical vein , chemistry , catalase , enzyme , superoxide dismutase , antioxidant , biochemistry , enzyme assay , biophysics , glutathione , biology , in vitro , organic chemistry
Nanomaterials having enzyme‐like activity (nanozymes) make them suitable candidates for various biomedical applications. In this study, we demonstrate the morphology‐dependent enzyme mimetic activity of Mn 3 O 4 nanoparticles. It is found that Mn 3 O 4 nanoparticles mimic the functions of all three cellular antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Interestingly, the nanozyme activity of Mn 3 O 4 depends on various factors including size, morphology, surface area, and the redox properties of the metal ions. The Mn 3 O 4 nanoflowers exhibited remarkably high activity in all three enzyme systems and the order of multienzyme activity of different morphologies was: flowers ≫ flakes > hexagonal plates≈polyhedrons≈cubes. Interestingly, all five nanoforms are taken up by the mammalian cells and were found to be biocompatible, with very low cytotoxicity. The activity of the most active nanoflowers was studied in primary human umbilical vein endothelial cells (HUVEC) and human pulmonary microvascular endothelial cells (hPMEC) and it was found that Mn 3 O 4 does not reduce the level of nitric oxide (NO). This is in contrast to the effect of some of the Mn‐porphyrin‐based SOD mimetics, which are known to scavenge NO in endothelial cells.