Analytical and Bioanalytical Chemistry
Electronic Supplementary Material
Effect of silica nanoparticles with different sizes on the catalytic activity
of glucose oxidase
Yingying Sun, Feng Yan, Weiwei Yang, Shuang Zhao, Wensheng Yang, Changqing
Sun
A
30 nm
B
60 nm
C
80 nm
D
100 nm
Absorbance
Absorbance
Fig. S1 TEM of ASNPs with different sizes.
a
240
260
280
300
320
340
Wavelength ( nm )
b
240
260
280
300
320
340
360
380
400
Wavelength ( nm )
Fig. S2 UV-vis absorption spectra of the ASNPs film with (a) and without
(b) GOx on the quartz slide. Inset shows UV of GOx dissolved in PBS
(pH 6.8).
Quartz slides used for UV-vis absorption was pretreated by piranha
solution (v/v = 3:7, 30% H2O2/98% H2SO4). Then the slides were placed
in dry toluene solution of APS to introduce amino-groups. The enzyme
films were constructed on the aminated quartz substrates by the same
procedures as those on the Au electrodes.
2.0
1.5
I / A
1.0
0.5
0.0
2.0
1.5
-0.5
1.0
I / A
0.5
-1.0
0.0
-0.5
-1.0
-1.5
-1.5
2
4
6
V
0.0
0.1
0.2
0.3
1/2
0.4
8
10
1/2
/ (mV/s)
0.5
E/V
Fig. S3 Cyclic voltammograms of Au/CA/GA/ASNPs/GOx in 0.1 M PBS
(pH 6.8) containing 0.25 mM ferrocenemethanol at different scan rates: 5,
10, 20, 30, 40, 50, 60, 80, 100 mV s-1 (from inside to outside),
respectively. The inset shows the relationship of anodic and cathodic peak
currents vs. the square root of scan rate.
Fig. S3 shows the cyclic voltammograms (CVs) of the glucose
biosensor in 0.1 M PBS (pH 6.8) containing 0.25 mM ferrocenemethanol
at different scan rates. The CVs were characterized by a redox couple
with formal potential E0'= (Epa + Epc)/2 at 228 mV. The peak potential
separation was 60 mV at a scan rate of 50 mV s-1. These waves were
assigned to one-electron reversible redox reaction of Fc+/Fc. When the
scan rate ranged from 5 mV s-1 to 100 mV s-1, the anodic peak currents
were almost the same as the corresponding cathodic peak currents and
both anodic and cathodic peak currents increased linearly with the square
root of scan rate (inset of Fig. S3), as expected for a diffusion-controlled
electron transfer process.