Affinity‐tuned peroxidase‐like activity of hydrogel‐supported Fe₃O₄ nanozyme through alteration of crosslinking concentration

Abstract

In this work, we evaluated the effect of crosslinking concentration on the affinity of poly (2-acrylamido-2-methyl-1-propansulfonic acid) (PAMPS) hydrogel-supported Fe 3 O 4 nanozyme towards substrates (tetramethylbenzidine (TMB) and H 2 O 2 ). The peroxidase-like catalytic activity of PAMPS/Fe 3 O 4 nanozyme was discussed with respect to crosslinking concentration of PAMPS hydrogel for the oxidation of TMB in the presence of H 2 O 2 at room temperature. High catalytic activity was achieved due to good dispersion of Fe 3 O 4 nanozyme in the hydrogel network and strong affinity of PAMPS hydrogel-supported Fe 3 O 4 nanozyme towards substrates. The affinity between the hydrogel-supported Fe 3 O 4 nanozyme and substrates can be improved by regulating the crosslinking concentration of PAMPS hydrogel without other trenchant experimental conditions. In addition, the result indicated that H 2 O 2 can be detected even at a concentration as low as 1. 5 3

Iron Oxide Nanozyme: A Multifunctional Enzyme Mimetic for Biomedical Applications

“…All these beneficial functions of Fe 3 O 4 NPs may be ascribed to the catalase-like activity reducing intracellular oxidative stress. Although promising results are displayed, the cellular roles of IONzyme still need to be evaluated carefully, as some work has reported it may increase ROS levels 114 . Taken together, the enzyme-like activities of IONzyme provide a new way to understand the potential functions of iron oxide nanomaterials taken up by the cell and may be used to control cellular ROS for therapeutic purposes.…”

Magnetogels: Prospects and Main Challenges in Biomedical Applications

“…This system was capable of detecting glucose based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 that results from glucose oxidation by glucose oxidase, producing a blue color with a maximum absorbance at 652 nm and attaining a detection limit of glucose of 38.5 μmol/L. In another approach, Sang et al [ 57 ] developed poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) based magnetogel containing Fe 3 O 4 and evaluated the effect of cross-linking concentration on the peroxidase-like activity ( Figure 1 ). The system showed the best catalytic activity for low cross-linking concentrations, which the authors suggest being associated to the enhancement of system affinity towards the substrate and due to the good dispersion of Fe 3 O 4 , having attained a detection limit of 1.5 × 10 −6 mol L −1 with a linear detection range of 1.5–9.8 × 10 −6 mol L −1 [ 57 ].…”

“…In another approach, Sang et al [ 57 ] developed poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) based magnetogel containing Fe 3 O 4 and evaluated the effect of cross-linking concentration on the peroxidase-like activity ( Figure 1 ). The system showed the best catalytic activity for low cross-linking concentrations, which the authors suggest being associated to the enhancement of system affinity towards the substrate and due to the good dispersion of Fe 3 O 4 , having attained a detection limit of 1.5 × 10 −6 mol L −1 with a linear detection range of 1.5–9.8 × 10 −6 mol L −1 [ 57 ]. The reader is referred to other articles if has an interest in the exploration of catalysis with magnetogels [ 58 , 59 , 60 , 61 ].…”

“…Magnetic nanoparticles, mainly iron oxide nanoparticles, have been playing an important role as T 2 contrast agents, due to their chemical stability and biodegradability, which can be explored in the monitorization of diseases and detection of injuries or deficiencies [ 87 , 88 ]. Though, it has also been reported that SPIONS suffer from peroxidase-like activity [ 56 , 57 ], which may eventually produce undesirable effects in the long-term due to the production of ROS, thus requiring a proper coating or the development of alternative nanoparticles. For example, cobalt nanoparticles exhibit a higher room temperature saturation magnetization (1422 emu cm −3 ) than iron oxide nanoparticles (395 emu cm −3 ), which can be explored to attain smaller particle core sizes without compromising sensitivity and achieve better magnetic resonance imaging contrast [ 87 ].…”

“…The nanoparticles are then formed by co-precipitation in an ammonia aqueous solution that ( C ) results in the magnetogel. Adapted from [ 57 ] with permission from John Wiley and Sons, 2015.…”