# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
Supplementary Information:
S-1 shows the TEM image of the MSA capped Au nanoparticles. The synthesis of
the MSAGNP followed the method described by S. Chen and K. Kimura (S. Chen
and K. Kimura, Langmuir, 1999, 15, 1075), which was based on the reduction of
hydrogen tetrachloroaurate(Ш) by sodium borohydride in methanol using MSA as
the stabilizing thiol ligand. The particle size can be easily controlled by the initial
molar ratio of MSA/HAuCl4. In our case, the molar ratio is 1:1. TEM image
shows that the MSAGNP are well-seperated, and the average particle size is about
2  0.5 nm.
S-2 shows the cyclic voltammograms of PANI/MSAGNP measured in buffers with
different pH values: for pH 1, HCl was used; for pH 3~8, 0.1M citrate phosphate
buffer was used. Scan rate was 20mV/s. In low pH solution, two separate redox
peaks appear, as the pH increases, the second redox peak moves quickly toward
low potentials with a rate of about –100mV/pH and finally merges with the first
one at pH > 5 to show only one redox peak. Similar phenomena were also
observed for PANI doped by other methods( see references 7,9,11).
S-3 shows the cyclic voltammograms of different bilayers of PANI/MSAGNP
measured in 0.1M PBS buffer, pH 7.1 with and without 5mM NADH. The inset
shows that the electrocatalytic efficiency of the film increases with the increase of
the number of bilayers up to at least 12 bilayers.
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
S-1 TEM image of the MSA capped Au nanoparticles.
4
I / µA
0
-4
pH=3
pH=1
pH=5
-8
pH=7
-12
pH=8
-0,2
0,0
0,2
0,4
E/V
0,6
0,8
S-2 cyclic voltammograms of PANI/MSAGNP measured in buffers with different
pH values: for pH 1, HCl was used; for pH 3~8, 0.1M citrate phosphate buffer
was used. Scan rate 20mV/s.
12
8
anodic catalytic current / µA
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
7
with 5mM NADH
6
5
4
2
2
4
I / µA
12
10
8
6
4
2
3
4
6
8
10
number of bilayers
12
0
2
4
6
8
10
12
-4
-8
-0,2
-0,1
0,0
0,1
0,2
0,3
E/V
S-3 Cyclic voltammograms of different bilayers of PANI/MSAGNP measured in
0.1M PBS buffer, pH 7.1 with and without 5mM NADH. The inset shows the
relationship between the electrocatalytic ability and the number of bilayers.