Manganese‐Based Nanozymes: Multienzyme Redox Activity and Effect on the Nitric Oxide Produced by Endothelial Nitric Oxide Synthase

Abstract

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 O nanoparticles. It is found that Mn O 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 O depends on various factors including size, morphology, surface area, and the redox properties of the metal ions. The Mn O 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 O 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.

<p>Manganese Oxide Nanozymes Ameliorate Mechanical Allodynia in a Rat Model of Partial Sciatic Nerve-Transection Induced Neuropathic Pain</p>

“…44,45 MONPs are reported to selectively scavenge superoxide ( • O 2 − ) species but not nitric oxide (NO • ) species. 46 This could have resulted in attenuation of mechanical allodynia without the attenuation of thermal hyperalgesia. We next investigated whether MONPs administration has any efficacy against nociceptive pain though tail flick test and we found no efficacy against nociceptive pain as expected ( Figure S4).…”

Progress and Trend on the Regulation Methods for Nanozyme Activity and Its Application

“…The shape and morphology of nanozymes plays a key role in regulating their catalytic activity [49][50][51][52]. Tian et al have investigated the effect of different morphologies (nanosheets, nanofibers, and nanorods) of VO 2 nanoparticles on the colorimetric assay for H 2 O 2 and glucose [53].…”

One-pot synthesis of biomimetic glutathione peroxidase with temperature responsive catalytic behaviors

“…Based on the research on the crystal structure of GPx and the investigation of biomimetic GPx, it was indicated that hydrophobic cavity derived from the hydrophobic amino acid residues of 150 Phe, 148 Trp, and 34 Leu played an important role in maintaining the high catalytic activity. 1,2 In this study, the hydrophobic structure of the natural GPx was simulated using the hydrophobic microenvironment derived from the PNIPAM polymer scaffold during the temperature responsive process.…”

“…Generally, the scaffold materials for preparing biomimetic GPx mainly include small organic molecules, 12,13,[20][21][22] imprinted proteins, 8,11 genetically engineered proteins, 14,15,23 supramolecular polymers, 17,19,24,25 block polymers, [26][27][28][29] microgels, [30][31][32] and organic-inorganic hybrid materials. [33][34][35][36] Compared with natural GPx, these biomimetic GPx were endowed with obvious advantages, such as high preparation yield, strong structural stability and good industrialization prospect. Among the scaffold materials of these biomimetic GPx, the microgel scaffold exhibits unique characteristics.…”