Enhanced Peroxidase-Like Performance of Gold Nanoparticles by Hot Electrons

Article abstract of DOI:10.1002/chem.201605380

Enzyme mimics have been widely used as alternatives to natural enzymes. However, the catalytic performances of enzyme mimics are often decreased due to different spatial structures or absence of functional groups compared to natural enzymes. Here, we report a highly efficient enzyme-like catalytic performance of gold nanoparticles (AuNPs) by visible-light stimulation. The enzyme-like reaction is evaluated by the catalytic reaction of AuNPs oxidizing a typical chromogenic substrate 3,3′,5,5′-tetramethylbenzydine (TMB) with hydrogen peroxide as an oxidant. From investigations of the wavelength-dependent reaction rate, radical capture, hole-donor addition, and dark-field scattering spectroscopy experiments, it is revealed that the strong plasmonic absorption of AuNPs facilitates generation of hot electrons, which are transfered from AuNPs to the adsorbed reactant molecule, greatly promoting the catalytic performance of the enzyme-like catalytic reaction. The present work provides a simple method for improving the performance of enzyme mimics, which is expected to find further application in the field of plasmon-enhanced biocatalysis and biosensors.

Full text of DOI:10.1002/chem.201605380

A Journal of
Accepted Article
Title: Enhanced peroxidase-like performance of gold nanoparticles by
hot electrons
Authors: Xinghua Xia, Chen Wang, Yi Shi, Xing-Guo Nie, Yuan-Yuan
Dan, and Jian Li
This manuscript has been accepted after peer review and appears as an
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of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
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the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.201605380
Link to VoR: http://dx.doi.org/10.1002/chem.201605380
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Enhanced peroxidase-like performance of gold nanoparticles by
hot electrons
Chen Wang,[a,b] Yi Shi,[a] Yuan-Yuan Dan,[a] Xing-Guo Nie,[b] Jian Li,[a] and Xing-Hua Xia*[a]
Abstract: Enzyme mimics have been widely used as alternatives to
natural enzymes. However, the catalytic performances of enzyme
mimics are often decreased due to different spatial structures or
absence of functional groups compared to natural enzymes. Herein,
we report a highly efficient enzyme-like catalytic performance of gold
nanoparticles (AuNPs) by visible light stimulation. The enzyme-like
reaction is evaluated by the catalytic reaction of AuNPs oxidizing a
typical chromogenic substrate 3, 3′, 5, 5′-tetramethylbenzydine (TMB)
with hydrogen peroxide as an oxidant. By investigations of the
wavelength dependent reaction rate, radical capture, hole donor
addition, and dark field scattering spectroscopy experiments, it is
revealed that the strong plasmonic absorption of AuNPs facilitates hot
electrons generation which transfers from AuNPs to adsorbed
reactant molecule, greatly promoting the catalytic performance of the
enzyme-like catalytic reaction. The present work provides a simple
method for improving enzyme mimics performance, which is expected
to find further application in the field of plasmon enhanced biocatalysis
and biosensors.
systems with high catalytic efficiency comparable to natural
enzymes.[12]
In recent years, AuNPs with different surface modifications
have been found to exhibit GOx- or peroxidase-like activity.[7a, 7c,
7d]
Compared with other nanomaterial-based enzyme mimics,
AuNPs as nanozymes are more prominent for bioanalysis due to
their comparable size to natural enzymes, routine preparation
method, excellent stability, and good biocompatibility.[13] For
example, Li group[7c] reported that AuNPs possess unique
peroxidase-like activity using colorimetric method. Chen and co-
workers performed a systematic study, further confirming that
AuNPs have peroxidase-like activities.[14] However, the potential
of AuNPs as enzyme mimics is limited by their relatively low
catalytic activities.[15]
The emergence and recent advance of plasmon
photocatalysis open new opportunities for the development of
nanoparticles with stable and high catalytic activity.[16] By light
irradiation, collective oscillation of free electrons in noble metal
nanoparticles (especially for Au, Ag, Cu) is driven by the
electromagnetic field of incident light, which is called localized
surface plasmon resonance (LSPR).[16] This unique LSPR
property of noble metal nanoparticles has been used for a variety
Due to the high specificity and efficiency for substrates conversion,
enzymes play important roles in life science, which can catalyze
more than 5000 biological processes with 1010–1015 fold rate
enhancements compared to uncatalyzed reactions.[1] However,
the complicated processes along with the high costs of
preparation, purification and storage have severely hampered the
widespread application of the natural enzymes.[2] As alternative
candidates, nanostructured materials with high surface energies
and large surface-to-volume ratio have been widely used as the
enzyme mimics.[3] In comparison with the natural enzymes,
nanomaterial based enzyme mimics exhibit a high stability,
tunable activity and less cost, which have shown immense
potential in chemical and biological reactions, pharmaceuticals,
anti-biofouling techniques, and clean fuels.[3] So far, a variety of
nanoscaled materials, such as CuO,[4] Fe3O4,[5] Co3O4,[6] gold
nanoparticles (AuNPs),[7] V2O5,[8] graphene oxide,[9] Prussian
blue,[10] and carbon nanotubes,[11] have been discovered to
possess unique enzyme-like catalytic activities. The robust
enzyme mimics allow us to catalyze a myriad of reactions under
desired conditions. However, there are still critical challenges we
have to overcome. For example, few enzyme mimics can achieve
comparable catalytic activities as the natural enzymes due to
structural difference or absence of functional groups.[3a]
of
applications
including
sensors,[17]
solar
cells,[18]
nanomedicine[19] and theranostics.[20] Researchers have
successfully introduced this unique property in the new field of
plasmonic enhanced chemical transformations.[21] Previously, we
made use of LSPR effect of gold nanorode to improve the catalytic
activity of hydrogen evolution reaction (HER) using
nanorode/MoS2 composite as catalyst.[22] Interestingly, a greatly
enhanced HER performance was observed upon light irradiation.
Further mechanism investigations by dark-field scattering
spectroscopy
(DFS),[22]
surface
enhanced
Raman
spectroscopy,[23] and theoretical model[24] revealed that efficient
surface plasmon excitation and decay followed by hot carriers
generation is responsible for the enhanced catalytic performance.
Recent advances in plasmon based photocatalysis inspires
us to focus this unique LSPR effect on enzyme-like reactions.
Herein, AuNPs are used as peroxidase mimics, which catalyze
the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) into TMB+ in
presence of H2O2 (Equation S1). The peroxidase-like reaction
performance is then investigated with and without LSPR
excitation. It is found that the peroxidase-like catalytic
performance can be greatly enhanced upon LSPR excitation. By
investigations of radical capture, donor addition, and dark field
spectroscopy experiments, a hot electrons induced performance
enhancement mechanism is suggested. Upon LSPR excitation,
the energetic electrons (referred as “hot electrons”) are
redistributed to the energy levels above the Fermi level. Due to
energy matching, the hot electrons are injected into adsorbed
H2O2 molecular orbit, which activates the H2O2 molecule and
further cleaves it into OH• radical which oxidizes TMB substrate
with much faster rate compared to the reation in dark.
[a]
[b]
Dr. C. Wang, Y. Shi, Prof. X. H. Xia State Key Laboratory of
Analytical Chemistry for Life Science and Collaborative Innovation
Center of Chemistry for Life Sciences, School of Chemistry and
Chemical Engineering, Nanjing University, Nanjing 210093, China
E-mail: xhxia@nju.edu.cn.
Dr. C. Wang, X. G. Nie, Key Laboratory of Biomedical Functional
Materials, School of Science, China Pharmaceutical University,
Nanjing, 211198, China
Supporting information for this article is given via a link at the end of
the document.
AuNPs were prepared according to the classic Frens
method.[25] The resultant 15 nm spherical AuNPs display a LSPR
Researchers have long sought to pursue to simple biomimetic
1
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absorbance at 521 nm in solution and 530 nm on glass substrate
(Figure 1a). The difference in the absorbance peaks is caused by
energy dissipation and substrate effect.[26] Transmission electron
microscopy (TEM, JEOL-JEM-200CX microscope, Japan) image
is shown in the inset in Figure 1a. All UV-vis spectra
measurements were carried out on an UV-vis spectrophotometer
(Shimadzu UV-3600). A visible light source of 532 nm with
intensity of 200 mW cm-2 (2-3 times solar intensity) was used for
light irradiation. The solution pH of the studied systems was
controlled at 5.0 using 10 mM PBS buffer.
The enzyme-like catalytic performance of AuNPs was
evaluated by catalysis of the peroxidase substrate TMB in the
presence of H2O2. The experiment details refer to the
“experimental section“ in supporting information. Upon addition of
AuNPs to TMB–H2O2 mixture system, the solution turns into light
blue color, showing a maximum absorbance at 652 nm (Figure 1b,
black curve). This absorbance originates from the oxidation of
TMB to TMB+. There should be a small peak of AuNPs
absorbance at around 530 nm. But the intensity of this peak is
relatively small as compared to the large absorbance of TMB+
ranging from 530 nm to 770 nm, and thus is completely covered
by TMB+ absorbance. Therefore AuNPs absorbance at 530 nm
cannot be observed here. When light (532 nm, 200 mW/cm2) is
on, an obviously increase (ca. 1.6 times) in UV-vis absorbance
appears (Figure 1b, red line), showing an enhanced enzyme-like
catalytic performance of AuNPs upon light stimulation.
at 670 nm in Figure 1c, which is different from the peak
absorbance of 652 nm in Figure 1b. This result indicates that there
could be due to the different oxidation product of TMB by AuNPs
without the presence of H2O2. The absorbance intensity in system
(1) keeps nearly constant over a period of 40 min reaction time
(Figure S1), demonstrating a limited catalytic capacity of AuNPs
toward TMB. For system 2 (H2O2 + TMB), light irradiation does
not have obvious effect on the reaction. In addition, much less
absorbance intensities appear (< 0.02), indicating a very weak
oxidation capacity of H2O2 toward TMB without AuNPs catalyst.
Although the reaction of system (2) continuously proceeds within
an hour (Figure S2), the reaction rate is relatively sluggish which
can be ignored compared to the reaction system in Figure 1b.
These two control experiments prove that the enhancement of the
reaction performance does originate from the enzyme-like activity
of AuNPs.
Figure 2. (a) Time dependent UV-vis spectra for the enzyme-like catalytic
reaction by AuNPs with light on (532 nm, 200 mW/cm2, from bottom to up: 0-
120 min). (b) The absorbance peak intensities in Figure 2a (on) and Figure S3
(off) versus the reaction time with light on (red dots) and off (black dots). (c)
Steady-state kinetic assay using the Michaelis−Menten model by varying H2O2
concentration at a fixed TMB concentration (1.2 mM) with light on and off. (d)
The double reciprocal plots of the enzyme-like reaction of AuNPs with light on
and off.
The enzyme-like reation kinetics catalyzed by AuNPs was
investigated at room temperature (25 0C) by monitoring the
changes in the absorbance spectra at different reaction time
(Figure S3). We find that the absorbance of the catalytic product
increases much faster with light on (Figure 2a) than in dark
(Figure S3). This illumination enhanced catalytic performance of
AuNPs is more clearly displayed in the plot of absorbance
intensity as function of reaction time (Figure 2b). The enzyme-like
reaction kinetics was further monitored with different H2O2
concentration (from 1 to 50 mM) and fixed TMB concentration (1.2
mM). The typical Michaelis-Menten curves of enzyme reaction are
obtained (Figure 2c), where the reaction velocity increases
linearly at low substrate concentration and reaches a plateau at
higher substrate concentration. Using the Lineweaver-Burk
double-reciprocal plot (Figure 2d) of Michaelis−Menten Equation,
the apparent Michaelis-Menten constant (Km) and the maximum
reaction rate (Vm) could be achieved.[27] Then, the catalytic
constant kcat was derived in terms of the equation Vm = kcat [E],
Figure 1. (a) UV–vis absorbance spectrum of the dilute aqueous solution of 15
nm AuNPs (black curve) and diffuse reflectance extinction spectrum of AuNPs
deposited on a glass in air (red curve). Inset shows the TEM image of AuNPs.
(b) UV–vis spectra of the enzyme-like system at a reaction time of 20 min with
and without illumination (532 nm, 200 mW/cm2). Concentration: 1.2 mM TMB,
20 mM H2O2, and 2.6 nM AuNPs. Red curve (light on), black curve (light off). (c)
UV–vis spectra of AuNPs and TMB mixture system (1.2 mM TMB, 2.6 nM
AuNPs) at a reaction time of 20 min. (d) UV–vis spectra of 1.2 mM TMB and 20
mM H2O2 mixture system at reaction time of 20 min.
To explore the reasons for this promoted catalytic
performance, two additional control experiments were performed
including systems (1): AuNPs + TMB and (2): H2O2 + TMB. Figure
1c shows the UV-vis absorbance spectra of system (1) with light
on and off. It is clear that there is nearly no obvious difference in
the absorbance spectra with light on and off, which indicates that
light irradiation does not have any effect on this system. Besides
the absorbance peak at 530 nm of AuNPs, there appears a peak
2
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where [E] is the enzyme concentration.[27b,27c] The results are
listed in Table 1, which clealry show that a much faster catalytic
rate and lower Km value are achieved with light on as compared
to the dark system. Lower Km value indicates higher affinity of the
enzyme to the substrate.[27] Thus, Illumination increases the
enzyme-like activity of AuNPs, although the reaction mechanism
is not changed.
Figure 3c); the second is depleted via the oxidation of water
(channel II) and the third is scavenged by additional electron
donors such as ethanol (EtOH) (channel III). In acidic condition
(pH 5.0), the dominant reaction pathway for the generated OH-
anions is its reaction with H+ ions to form water molecules. Thus,
Channel II is considered as the main pathway for holes
scavenging if there is no additional electron donors. The efficient
scavenging of holes can reduce the recombination probability of
hot eletrons and holes, contribute to fast cleavage of H2O2 into
•OH radical, and accordingly increase the reaction rate greatly. In
addition, upon LSPR excitation, the intense local electric fields
near the surface of AuNPs arises, which could also result in an
increased amount of hot carriers generation locally in AuNPs.[16]
Table 1. The Apparent Michaelis-Menten constant (Km), maximum reaction
rate (Vm), and catalytic constant (kcat) for the enzyme-like performance of
AuNPs with light on or off.
Km (mM)
25.21
Vm (μM s-1)
15.57
kcat (s-1)
5990.9
off
on
14.71
43.86
16869.1
To get insight into the mechanism of the enhanced enzyme-
like catalytic performance of AuNPs upon light irradiation, the
influence of light wavelength and light intensity were first
investigated. As revealed in Figure 3a, the absorbance peak
intensity changes with the wavelength of illumination (black
columns), and a maximum is observed at 532 nm. This trend
nearly overlaps with the plasmonic excitation of 15 nm AuNPs on
a glass substrate (red curve in Figure 3a), suggesting that LSPR
effect of AuNPs is responsible for the observed absorbance
change.[21c,21d] In addition, the absorbance peak intensity shows
linear increase with the illumination intensity in a range of 0 - 300
mW cm−2, then transits from linear to super-linear dependence
beyond 300 mW cm−2 (Figure 3b). Similar relationship between
reaction rate and light intensity was observed previously,[21d]
which is a signature of hot carriers related photochemical
reactions by LSPR excitation, demonstrating more efficient
production of hot carriers with stronger light intensities. Under light
irradiation, the hot electrons are generated by LSPR of AuNPs. In
the linear regime, some hot electrons have not enough energy to
overcome the activation barrier, and thus would return to the
equilibrium thermal state. However, when the irradiation intensity
is high enough, more hot electrons energy becomes sufficiently
high to overcome the activation barrier, which results in more
efficient enhancement of enzyme mimics performance, and the
transition to the super-linear regime occurs.
Based on the above experimental results, a possible reaction
mechnism of hot electrons activated enzyme-like catalytic activity
is proposed (Figure 3c). It is well known that noble metal
nanoparticles can generate a great number of hot carriers upon
LSPR excitation.[16-24] In the case of AuNPs based enzyme-like
system, the catalytic reaction is initiated with the adsorption of
H2O2 moelcules on AuNPs surface.[10] Upon LSPR excitation, hot
electrons and holes are generated. Due to energy matching, the
hot electrons would be injected into the molecular orbitals of H2O2,
which activates the adsorbed H2O2 molecule into a transition state
followed by decomposing into •OH radical and OH- anion. The
generated •OH radical is a very reactive species with a standard
redox potential of +2.8 V,[28] which could be stabilized by AuNPs
via the partial electron exchange interaction,[29] and contributes to
the fast oxidation of TMB. The holes can be scavenged by
electron donors through three pathways: the first one is consumed
by thegenerated OH- anions during H2O2 cleavage (chanel I in
Figure 3. (a) Wavelength dependent peak intensity change of the UV-vis
spectra at 652 nm for AuNPs based enzyme-like reaction system (illuminated
using 532 nm laser with 200 mW/cm2, black columns) and LSPR spectrum (red
solid curve) of 15 nm AuNPs (530 nm). (b) Change of the peak intensities
(normalized) of UV-vis spectra at 652 nm for the enzyme-like reaction as a
function of light intensity. (c) Illustration of the proposed mechanism for LSPR
enhanced enzyme-like performance of AuNPs. (d) Fluorescence spectra of
HTPA (product of the reaction of 0.1 mM TPA with •OH) taken after different
reaction time upon LSPR excitation. The fluorescence excitation wavelength
was 315 nm. (e) The corresponding peak fluorescence intensity versus reaction
time with LSPR excitation on and off.
To verify the generation of •OH radicals, experiments with a
capture reagent of terephthalic acid (TPA) which can react with
•OH to form a fluorescent product 2-hydroxyterephthalic acid
(HTPA) with the characteristic photoluminescence (PL) at 430 nm
were performed.[30] The fluorescence spectra at different reaction
times with LSPR excitation on and off are shown in Figure 3d (on)
and Figure S4 (off), and the corresponding peak intensities are
shown in Figure 3e. The fluorescence intensity of HTPA increases
continuously with the reaction time upon LSPR excitation,
providing the direct evidence of the generation of •OH radical. In
3
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comparison, with LSPR excitation off, the fluorescence intensity
shows nearly constant with the reaction time, suggesting a much
less efficient production of •OH radical in thedark system.
According to the proposed mechanism, the reaction rate
could be further improved if the electron donors are added, which
leads to more efficient separation of hot electrons and holes.
Herein, ehtanol (EtOH) was chosen as the electron donor, and
that due to the stronger reduction capacity of AA, part TMB+
molecules could be directly reduced by AA into TMB, thus leading
to a reduced amount of TMB+. This concentration decrease
competes with electron donor induced transformation
enhancement, eventually leading to a nearly constant absorbance
intensity. To verify the proposed assumption, the reaction kinetics
of AA system without illumination was investigated (Figure 4d). It
the enzyme-like performance with EtOH addition was investigated. is clear that except for the initial 5 min which needs to reach the
As shown in Figure 4a, when EtOH exists (final concentration: 10
vol %), the UV-vis absorbance peak intensity increases from 0.51
(PBS system) to 0.85 (EtOH system) upon LSPR excitation. The
absorbance peak intensities (normalized) with and without EtOH
were compared upon continuous LSPR excitation (Figure 4b). It
reveals that in both cases the absorbance intensities increase
with light irradiation time. but the increasing magnitude of the
reaction system with EtOH (red curve) is obviously larger than
pure PBS system (black curve). This phenomenon is caused by
the faster scavenging of holes by electron donor EtOH (channel
III in Figure 3c) than H2O (channel II in Figure 3c). To further verify
the proposed function of EtOH in this light enhanced reaction
system, gas chromatograph (GC, Agilent 7890B) was used to
detect the product of the reaction system. From the results in
Figure S5, it can be clearly found that acetaldehyde (CH3CHO)
and acetic acid (CH3COOH) are formed after the light irradiation,
which is the oxidation product of EtOH by holes in AuNPs. These
results confirm the proposed mechanism of hot electrons
enhanced enzyme-like catalytic performance of AuNPs.
reaction equilibrium, the absorbance peak intensity keeps
continously declining with the reaction time, revealing the indeed
decrease of TMB+ concentration when AA exists in the system.
Figure 5. (a) Schematic apparatus for in-situ dark field scattering spectroscopy
measurement in 10 mM PBS (pH 5.0). (b) Dark field image of 50 nm AuNPs
deposited on a glass in 10 mM PBS, scale bar: 1 μm. Inset shows the TEM of
50 nm AuNPs. (c) Dark field scattering spectroscopy of a single AuNP on glass
(the intensities were normalized). Black line: 10 mM PBS buffer; red line: 10
vol % EtOH system for 20 min illumination; blue line: addition of TMB and H2O2
into above system. The final concentrations of TMB, H2O2, EtOH were 1.2 mM,
20 mM, and 10 vol %, respectively.
To provide direct evidence supporting the above-proposed
mechanism of hot electrons enhanced enzyme-like catalytic
performance, dark field scattering spectroscopy monitoring
electron density of single AuNP in real-time was performed. The
setup is schematically illustrated in Figure 5a. First, 50 nm AuNPs
were modified on the glass slide (the experimental details refer to
supporting information), which appear as green color dots in 10
mM PBS in the dark-field image (Figure 4b, inset shows the TEM
of 50 nm AuNPs). The scattering peak of AuNPs in PBS buffer
appears at 550 nm (black line in Figure 5c), which is about 18 nm
red shifted as compared to the absorbance peak in solution (532
nm, Figure S7) due to the energy dissipation and substrate
effect.[26] Then, EtOH was added (final concentration 10 vol % in
10 mM PBS), and the scattering spectroscopy after 20 min
illumination was recorded as the blue line in Figure 5c. It can be
clearly seen that a blue shift of ～9.0 nm (from 550 to 541 nm)
after 20 min illumination appears. Blue shift suggests an
increased electron density in AuNPs. Due to the efficient depletion
of hot holes by EtOH, excessive hot electrons remain in AuNPs,
resulting in a higher electron density transiently. When H2O2 and
TMB was added, these hot electrons would transfer to H2O2
molecule, leading to generation of •OH radical and oxidation of
TMB, which would decrease the electron density in AuNPs again.
This discharging process would make red shift in the scattering
spectroscopy, as observed in Figure 5c, red line. The result of
Figure 4. (a) The UV-vis spectra of EtOH system with LSPR excitation on and
off. (b) The changes of the UV-vis absorbance peak intensities (normalized at
652 nm) versus the reaction time upon LSPR excitation. Black curve: PBS
system. Red curve: EtOH system. (c) The UV-vis spectra of AA system with
LSPR on and off. (d) The UV-vis absorbance peak intensity as a function of the
reaction time for AA system in dark. The concentration of EtOH solution was 10
vol %, and AA was 100 mM.
However, an unexpected phenomenon occurs when another
electron donor ascorbic acid (AA,100 mM) is added instead of
EtOH (Figure 4c). There is no obvious change in UV-vis
absorbrance spectra whether light is on or off for AA system. To
explain this “abnormal“ phenomenon, we perfomred cyclic
voltammograms (CVs) of EtOH and AA (Figure S6 in supporting
information). The CVs show that AA has relatively stronger
reduction capacity compared to EtOH. Therefore, it is estimated
4
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In conclusion, our results demonstrate that the enzyme-like
catalytic performance of AuNPs could be significantly enhanced
by visible light irradiation. It is revealed that upon LSPR excitation,
hot carriers (hot electrons and holes) are generated on AuNPs
surface. The efficient injection of hot electrons into the molecular
orbits of absorbed H2O2 activates H2O2 molecule, accelerating the
cleavage of H2O2 into •OH radical. Due to the super oxidation
capacity of •OH radical, a much faster oxidation rate and
enhanced enzyme-like performance can be observed. The
efficiency of the hot electron injection can be further increased by
scavenging the generated hot holes using electron donor like
ethanol. The present work would shed some insights on the
mechanism of plasmon activated enzyme-like reaction, offering a
new strategy for improving performance of the enzyme mimics.
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Acknowledgements
This work is supported by grants from the National Natural
Science Foundation of China (21327902, 21575163, 21635004),
the Natural Science Foundation of Jiangsu Province
(BK20151437). The authors declare that they have no competing
interests.
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Keywords: enzyme mimics • localized surface plasmon
resonance (LSPR) • hot electrons • reaction mechanism • gold
nanoparticles (AuNPs)
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10.1002/chem.201605380
Chemistry - A European Journal
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Upon visible light irradiation, strong
plasmonic absorption of AuNPs
facilitates hot electrons formation on
AuNPs surface. Due to energy
Chen Wang, Yi Shi, Yuan-Yuan Dan,
Xing-Guo Nie, Jian Li, Xing-Hua Xia*
Page No. – Page No.
matching, the hot electrons will inject
Enhanced peroxidase-like
performance of gold nanoparticles by
hot electrons
into H2O2 molecular orbit, cleaving
H2O2 into OH• radical, which oxidizes
TMB into TMB+ rapidly, and enhance
the enzyme-like performance.
TOC Graphic hee))
6
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