Colorimetric detection of creatinine based on specifically modulating the peroxidase-mimicking activity of Cu-Fenton system

Enhanced peroxidase-like activity of MOF nanozymes by co-catalysis for colorimetric detection of cholesterol

“…In addition to the existence of Mo 6+ , two peaks with binding energy located at 234.9 eV and 231.6 eV were found, which were attributed to Mo 5+ and Mo 4+ , respectively. 26 Combined with the above analysis results, it was speculated that the addition of H 2 O 2 may promote the reduction of high-valence Mo and Cu. The reaction processes that may be involved were as follows:Cu 2+ + H 2 O 2 → Cu + + ˙O 2 − + H + Cu + + H 2 O 2 → Cu 2+ + ˙OH + HO − Mo 6+ + ˙O 2 − → Mo 4+ + 1 O 2 Mo 4+ + Cu 2+ → Mo 6+ + Cu + …”

“…The molybdenum-based transition metal is a multivalent metallic element, which can be used as an outstanding co-catalyst to improve the decomposition efficiency of H 2 O 2 due to the variability of its valence state. 26,27 Inspired by the above, we hypothesized that co-catalysts could be applied to regulate the catalytic activity of MOF nanozymes.…”

DNA-Mediated Graphene Oxide/Platinum Nanozymes for Label-Free Colorimetric Detection of Hg2+

“…TMB was used as a chromogenic substrate in the presence of H 2 O 2 to examine the peroxidase-mimetic activity of GO-DNA-PtNPs. 39 To investigate the effect of Hg 2+ on the catalytic activity, the same volume of Hg 2+ (500 nM) and distilled water were added to GO-DNA-PtNPs samples (4 μg/mL) in two tubes, respectively. Each tube received a successive addition of 10 mM sodium citrate buffer (pH 4.5), 6 mM H 2 O 2 , and 0.4 mM TMB.…”

Dipeptide Surface Modification and Ultrasound Boosted Phosphatase-Like Activity of the Ceria Nanozyme: Dual Signal Enhancement for Colorimetric Sensors

“…As the fact that the catalytic reactions of nanozymes occur on the surfaces of nanoparticles, improving the surface catalytic microenvironment is crucial for regulating the catalytic activity. , To date, various functional groups have been used to modify the surfaces of nanozymes, including anions, , nucleoside triphosphates, , dextran, , and amino acids, , among others. − These previous studies have demonstrated that surface modification is an effective means to regulate the catalytic activities of nanozymes. However, most studies carried out to date have focused on peroxidase- and oxidase-like redox-type nanozymes.…”