Microbial Enzymes in Nanotechnology …
213
cancer. Also, Hayat et al. (2015) studied the potential oxidase-like characteristics
of nanoceria particles in the creation of colorimetric assays for the detection of
dopamine and catechol. The limits of detection of 1.5 and 0.2 μM were observed
for dopamine and catechol respectively and similar assay was utilized as a sensing
system for the detection of other phenolics. However, the sensitivity of the system
was significantly dependent on the type of particle, composition of buffer, pH and
the configuration of the phenolic compounds.
Sennuga et al. (2011) reported the fabrication of platinum nanoparticles (PtNPs)
with ferroxidase-like using horse spleen apoferritin (HSAF) mixed with diverse
concentrations of K 2 PtCl 4 followed by a 20-fold concentration of sodium borohydride leading to a change in color from colorless or whitish yellow to brown. TEM
examination revealed that PtNPs with mean size of 2–6 nm were generated, while
FTIR confirmed that the PtNPs were attached to protein. The upshot of PtNPs on the
ferroxidase activity of HSAF displayed a precise activity of 360 ρmol min
−1 mg
−1 ,
(ninefold enhancement over the control). Also, according to Zhou et al. (2016), an
electrochemiluminescence (ECL) biosensor without background for the responsive
detection of DNA methyltransferase (MTase) potential was established dependent
on incorporating the catalytic utility of gold nanoparticles (AuNPs) for glucose and
the ECL enhancement of AuNPs for cadmium sulfide quantum dots (CdSQDs). The
glucose oxidase-mimicking AuNPs was synthesized via rapid stirring of 1% w/v
HAuCl 4 solution and heating at 100 °C, after which 1 wt% sodium citrate solution was
added up quickly, and the solution was kept boiling till the color changed from light
yellow to deep red. While the Cds QDs was synthesized by heating Cd(NO 3 ) 2 ·4H 2 O
suspended in ultrapure water at 70 °C under stirring, after which aqueous solution
of Na 2 S was slowly injected resulting in an orange-yellow solution.
Moreover, Han et al. (2018) reported the bovine serum albumin-directed method
for the fabrication of Manganese dioxide nanoflakes (MnO 2 NFs) whose morphology
could be tuned by adjusting the synthesis conditions. The MnO 2 NFs displayed twin
enzyme potentials (GOx-like and peroxidase-like activity) at comparable pH range.
Furthermore, the colorimetric detection of glucose, and H 2 O 2 were simultaneously
conducted under the catalysis of the single nanozyme (MnO 2 NFs). The method
used displayed low limit of detection, high sensitivity and short detection time, as
a result of the in situ reaction and proximity effect. Copper-containing carbon dots
(Cu-CDs) were produced via a nontoxic and single-pot hydrothermal technique (Ren
et al. 2015). The Cu-CDs possessed inherent laccase-like activities which catalyzed
the oxidation of p-phenylenediamine (PPD) (laccase substrate) to develop a characteristic color change from colorless to brown. Polymethacrylic acid sodium salt
(PMAA) was utilized as the carbon source, reducing agent and also assisted flocculation between Cu-CDs and polyacrylamide by providing carboxyl groups, which
aided the exclusion of PPD. Significantly, based on laccase mimics and fluorescence
quenching, the intrinsic fluorescence of the Cu-CDs could point out the occurrence
of hydroquinone.
Platinum nanoparticles were produced by employing different oligonucleotides
(A 10 , T 10 , C 10 and G 10 ,) as stabilizing agents and their catalytic activities were
213
cancer. Also, Hayat et al. (2015) studied the potential oxidase-like characteristics
of nanoceria particles in the creation of colorimetric assays for the detection of
dopamine and catechol. The limits of detection of 1.5 and 0.2 μM were observed
for dopamine and catechol respectively and similar assay was utilized as a sensing
system for the detection of other phenolics. However, the sensitivity of the system
was significantly dependent on the type of particle, composition of buffer, pH and
the configuration of the phenolic compounds.
Sennuga et al. (2011) reported the fabrication of platinum nanoparticles (PtNPs)
with ferroxidase-like using horse spleen apoferritin (HSAF) mixed with diverse
concentrations of K 2 PtCl 4 followed by a 20-fold concentration of sodium borohydride leading to a change in color from colorless or whitish yellow to brown. TEM
examination revealed that PtNPs with mean size of 2–6 nm were generated, while
FTIR confirmed that the PtNPs were attached to protein. The upshot of PtNPs on the
ferroxidase activity of HSAF displayed a precise activity of 360 ρmol min
−1 mg
−1 ,
(ninefold enhancement over the control). Also, according to Zhou et al. (2016), an
electrochemiluminescence (ECL) biosensor without background for the responsive
detection of DNA methyltransferase (MTase) potential was established dependent
on incorporating the catalytic utility of gold nanoparticles (AuNPs) for glucose and
the ECL enhancement of AuNPs for cadmium sulfide quantum dots (CdSQDs). The
glucose oxidase-mimicking AuNPs was synthesized via rapid stirring of 1% w/v
HAuCl 4 solution and heating at 100 °C, after which 1 wt% sodium citrate solution was
added up quickly, and the solution was kept boiling till the color changed from light
yellow to deep red. While the Cds QDs was synthesized by heating Cd(NO 3 ) 2 ·4H 2 O
suspended in ultrapure water at 70 °C under stirring, after which aqueous solution
of Na 2 S was slowly injected resulting in an orange-yellow solution.
Moreover, Han et al. (2018) reported the bovine serum albumin-directed method
for the fabrication of Manganese dioxide nanoflakes (MnO 2 NFs) whose morphology
could be tuned by adjusting the synthesis conditions. The MnO 2 NFs displayed twin
enzyme potentials (GOx-like and peroxidase-like activity) at comparable pH range.
Furthermore, the colorimetric detection of glucose, and H 2 O 2 were simultaneously
conducted under the catalysis of the single nanozyme (MnO 2 NFs). The method
used displayed low limit of detection, high sensitivity and short detection time, as
a result of the in situ reaction and proximity effect. Copper-containing carbon dots
(Cu-CDs) were produced via a nontoxic and single-pot hydrothermal technique (Ren
et al. 2015). The Cu-CDs possessed inherent laccase-like activities which catalyzed
the oxidation of p-phenylenediamine (PPD) (laccase substrate) to develop a characteristic color change from colorless to brown. Polymethacrylic acid sodium salt
(PMAA) was utilized as the carbon source, reducing agent and also assisted flocculation between Cu-CDs and polyacrylamide by providing carboxyl groups, which
aided the exclusion of PPD. Significantly, based on laccase mimics and fluorescence
quenching, the intrinsic fluorescence of the Cu-CDs could point out the occurrence
of hydroquinone.
Platinum nanoparticles were produced by employing different oligonucleotides
(A 10 , T 10 , C 10 and G 10 ,) as stabilizing agents and their catalytic activities were