Supporting Information
Aggregation-Induced Structure Transition of
Protein-Stabilized Zinc/Copper Nanoclusters for
Amplified Chemiluminescence
Hui Chen,†,‡ Ling Lin,§ Haifang Li,‡ Jianzhang Li,† and Jin-Ming Lin*,‡
†
MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University,
Beijing, 100083, China, ‡Department of Chemistry, Beijing Key Laboratory of Microanalytical
Methods and Instrumentation, The Key Laboratory of Bioorganic Phosphorus Chemistry &
Chemical Biology, Tsinghua University, Beijing, 100084, China, and §Faculty of Engineering, The
University of Tokyo, Tokyo 113-8654, Japan.
*Address correspondence to [email protected]; Fax: +86 10-6279-2343; Tel: +86
10-6279-2343.
S1
The powder X-ray diffraction (XRD) pattern of the as-prepared Zn/Cu@BSA NC shown in Figure
S1 was scanned from 10 o to 80 o at a scanning rate of 0.02 o s-1. The ultraweak and broad diffraction
peaks of Cu5Zn8 (310), (222) and (330) could be found in the as prepared Zn/Cu@BSA NC (Figure
S1, the red line), which indicated that the component in the nanocluster core was consistent with the
number of copper and zinc atoms as Cu5Zn8 obtained from MALDI-TOF mass spectrometry.
According to the XRD pattern of BSA treated as the preparation of Zn/Cu@BSA NC without the
addition of Zn(NO3)2 and CuSO4 solution (Figure S1, the black line), the broad peak between 18 to
25 degrees shown in Zn/Cu@BSA NC pattern was attributed to the amorphous scaffold of BSA.
Figure S1. X-ray diffraction patterns of Zn/Cu@BSA NC (red line), and BSA treated as the
preparation of Zn/Cu@BSA NC without the addition of Zn(NO3)2 and CuSO4 solution (black line).
S2
High resolution TEM images of Zn/Cu@BSA NC before and after CL reaction have been shown in
Figure S2. The nanoclusters (Figure S2a) fused to form nanocrystals in the presence of H2O2
(Figure S2b). Figure S2c was obtained after the CL reaction of Zn/Cu@BSA NC with NaHCO3 and
H2O2, providing insight into the structure of the Zn/Cu nanoparticles. The lattice structures of
nanoparticles could be seen clearly. The corresponding Fast Fourier Transform pattern of Zn/Cu
nanoparticles displays several diffraction rings due to numerous small nanocrystals within the
nanoparticle, further demonstrats the Zn/Cu polycrystals (Figure S2d).
Figure S2. High resolution TEM images of Zn/Cu@BSA NC before CL reaction (a), after addition
of H2O2 (b), and after the CL reaction with NaHCO3 and H2O2 (c), and (d) the corresponding Fast
Fourier Transform pattern of the arrow noted area in image (c).
S3
In flow injection analysis (FIA) CL system, the flow rate was 1.5, 1.0 and 1.0 mL min-1 for the
carrier (H2O), NaHCO3 and Zn/Cu@BSA NC, respectively (Figure S3). Firstly, NaHCO3 solution
mixed with Zn/Cu@BSA NC solution through a three-way piece. Then 100 µL H2O2 standard
solution or sample solution was injected into the flow line of carrier stream by a loop valve injector.
Finally H2O2 reacted with the mixture of Zn/Cu@BSA NC-NaHCO3 in a spiral flow CL cell which
was placed in front of the photomultiplier tube (PMT). The CL intensity was recorded as the peak
height.
Figure S3. Schematic diagram of the flow injection CL sensing system. P1 and P2, peristaltic
pumps; PMT, photomultiplier tube; the flow rate of carrier water was 1.5 mL min-1; the flow rates
of NaHCO3 and Zn/Cu@BSA NC were 1.0 mL min-1.
S4
Zn/Cu@BSA NC synthesized with different ion concentrations were studied in NaHCO3-H2O2 CL
system. The CL intensity decreased gradually when Zn/Cu@BSA NC was diluted more than 500
times (Figure S4a). Zn/Cu@BSA NC with ion concentration of 2.0 mM diluted 500 times can
enhance the CL to the maximum. Considering the sensitivity, 2.0 mM Zn/Cu@BSA NC diluted 500
times was selected for subsequent investigation.
The influence of pH on the CL of NaHCO3-Zn/Cu@BSA NC-H2O2 system and
NaHCO3-BSA-H2O2 system was investigated as shown in Figure S4b. Both systems had weak CL
when pH was below 7.0. The CL intensity was increased with increasing pH and reached the
maximum at pH 11.80 in NaHCO3-Zn/Cu@BSA NC-H2O2 system, and at pH 11.20 in
NaHCO3-BSA-H2O2 system, respectively. The effect of BSA on CL intensity of NaHCO3-H2O2
system at different pH value was very small. Therefore, pH 11.80 was selected in
NaHCO3-Zn/Cu@BSA NC-H2O2 system.
Figure S4. Effects of different concentration of reagents and pH on the CL intensity in FIA. (a)
Zn/Cu@BSA NC concentration and (b) pH of flow system.
S5
TABLE S1. Results of H2O2 Sensing and Recoveries in Water Samplesa
Sample
Proposed sensor
Comparison method
Added
Observed
Recovery
(µM)
(µM)
(µM)
(µM)
(%)
Tap water 1
0.17±0.01
0.18±0.01
0.10
0.26±0.01
90
Tap water 2
0.20±0.01
0.22±0.01
0.20
0.39±0.02
95
Tap water 3
0.29±0.01
0.26±0.01
0.30
0.60±0.02
103
a
Solution conditions were 0.2 M NaHCO3 and 2.0 mM Zn/Cu@BSA NC. Values were mean
values of three determinations and the standard deviation.
S6