216
J. A. Elegbede and A. Lateef
It was concluded that GOQDs could translocate into zebrafish brains and exercise
catalase-mimicking activity to prevent oxidation intracellularly.
Also, Liu et al. (2017b) reported that amine-terminated polyamidoamine
(PAMAM) dendrimer-encapsulated gold nanoclusters (AuNCs–NH 2 ) produced O 2
for photodynamic therapy (PDT) through their in-built catalase-like activity. The
AuNCs–NH 2 was produced by mixing 200 μL of 150 × 10
−3 M HAuCl 4 with
deionized water containing 94.9 μL of 5 μmol G 4 NH 2 (20 wt% methanol solution).
The mixture was incubated at 4 °C overnight before being irradiated by microwave
for 30 min. The AuNCs–NH 2 synthesized displayed optimal H 2 O 2 consumption
through its catalase-like activity in the physiological pH range (pH 4.8–7.4), and also
extended such activity to acidic pH conditions. The prospect to release O 2 through the
catalase-like potential of AuNCs–NH 2 for PDT against hypoxia of cancer cells was
studied also which presented the potentials of the AuNCs–NH 2 enabling effective
anticancer treatments.
Metal oxide-based nanoparticles have also been reported to produce inherent
catalase mimetic activities. Tian et al. (2018) illustrated the fabrication of the CuO
nanozyme by adding 10 mM copper nitrate solution to 5 mmol oxalic acid, the
mixture was magnetically stirred, and the suspension colloids obtained were washed
with distilled water and ethanol several times to purify the product, followed by
drying at 50 °C for 12 h. The CuO nanozyme was utilized as a catalyst in the ultrasensitive electrochemical detection of circulating tumor cells (CTCs) by employing
reduced graphene oxide/gold nanoparticles composites (rGO/AuNPs nanocomposites) as a support substance. The MCF-7 circulating tumor cells were sensed by
an electrochemical cytosensor having efficient surface recognition between MUC-1
aptamer and specific mucin 1 protein (MUC-1) over-expressed on the cell membranes
of MCF-7. The CuO nanozyme was utilized as a signal-amplifying nanoprobe in
an ultrasensitive electrochemical cytosensor. Also, Hu et al. (2017a; b) describe
the fabrication of hematite nanozyme by dissolving 20 mmol FeCl 3 and 0.4 mmol
KH 2 PO 4 in distilled water to produce a clear yellowish solution that was stirred
magnetically and heated under reflux for 72 h leading to a brown turbid dispersion which was filtered, precipitated and centrifuged to achieve a brown powder.
The hematite nanozyme were incorporated into electrospun and then cross-linked
polyvinyl alcohol membranes, where the polymeric mesh created a porous scaffold with improved water permeability, and the nanozyme functioned as a catalyst
with catalase-resembling potential that competently converted H 2 O 2 into O 2 . The
hematite nanozyme was utilized to support wound healing, and the results obtained
showed that the development of fibroblasts at an H 2 O 2 concentration of 50 μM was
principally improved when the nanozyme dressing was applied. Thus, the application of the nanozyme dressing can appreciably decrease the harmful effects of H 2 O 2
at higher concentrations.
Moreover, Chen et al. (2018) demonstrated MoS 2 nanosheets as a multifunctional nanozyme which possessed fundamental potentials resembling enzymes like
catalases, superoxide dismutases and peroxidases at certain physiological conditions
(pH 7.4, 25 °C). The MoS 2 nanosheets were fabricated by dissolving MoS 2 powder
in dispersion solvent containing a combination of ethanol and distilled water. This
J. A. Elegbede and A. Lateef
It was concluded that GOQDs could translocate into zebrafish brains and exercise
catalase-mimicking activity to prevent oxidation intracellularly.
Also, Liu et al. (2017b) reported that amine-terminated polyamidoamine
(PAMAM) dendrimer-encapsulated gold nanoclusters (AuNCs–NH 2 ) produced O 2
for photodynamic therapy (PDT) through their in-built catalase-like activity. The
AuNCs–NH 2 was produced by mixing 200 μL of 150 × 10
−3 M HAuCl 4 with
deionized water containing 94.9 μL of 5 μmol G 4 NH 2 (20 wt% methanol solution).
The mixture was incubated at 4 °C overnight before being irradiated by microwave
for 30 min. The AuNCs–NH 2 synthesized displayed optimal H 2 O 2 consumption
through its catalase-like activity in the physiological pH range (pH 4.8–7.4), and also
extended such activity to acidic pH conditions. The prospect to release O 2 through the
catalase-like potential of AuNCs–NH 2 for PDT against hypoxia of cancer cells was
studied also which presented the potentials of the AuNCs–NH 2 enabling effective
anticancer treatments.
Metal oxide-based nanoparticles have also been reported to produce inherent
catalase mimetic activities. Tian et al. (2018) illustrated the fabrication of the CuO
nanozyme by adding 10 mM copper nitrate solution to 5 mmol oxalic acid, the
mixture was magnetically stirred, and the suspension colloids obtained were washed
with distilled water and ethanol several times to purify the product, followed by
drying at 50 °C for 12 h. The CuO nanozyme was utilized as a catalyst in the ultrasensitive electrochemical detection of circulating tumor cells (CTCs) by employing
reduced graphene oxide/gold nanoparticles composites (rGO/AuNPs nanocomposites) as a support substance. The MCF-7 circulating tumor cells were sensed by
an electrochemical cytosensor having efficient surface recognition between MUC-1
aptamer and specific mucin 1 protein (MUC-1) over-expressed on the cell membranes
of MCF-7. The CuO nanozyme was utilized as a signal-amplifying nanoprobe in
an ultrasensitive electrochemical cytosensor. Also, Hu et al. (2017a; b) describe
the fabrication of hematite nanozyme by dissolving 20 mmol FeCl 3 and 0.4 mmol
KH 2 PO 4 in distilled water to produce a clear yellowish solution that was stirred
magnetically and heated under reflux for 72 h leading to a brown turbid dispersion which was filtered, precipitated and centrifuged to achieve a brown powder.
The hematite nanozyme were incorporated into electrospun and then cross-linked
polyvinyl alcohol membranes, where the polymeric mesh created a porous scaffold with improved water permeability, and the nanozyme functioned as a catalyst
with catalase-resembling potential that competently converted H 2 O 2 into O 2 . The
hematite nanozyme was utilized to support wound healing, and the results obtained
showed that the development of fibroblasts at an H 2 O 2 concentration of 50 μM was
principally improved when the nanozyme dressing was applied. Thus, the application of the nanozyme dressing can appreciably decrease the harmful effects of H 2 O 2
at higher concentrations.
Moreover, Chen et al. (2018) demonstrated MoS 2 nanosheets as a multifunctional nanozyme which possessed fundamental potentials resembling enzymes like
catalases, superoxide dismutases and peroxidases at certain physiological conditions
(pH 7.4, 25 °C). The MoS 2 nanosheets were fabricated by dissolving MoS 2 powder
in dispersion solvent containing a combination of ethanol and distilled water. This