Supporting Information
A Highly Parallel Microfluidic Droplet Method Enabling Single Molecule Counting for Digital Enzyme
Detection
Zhichao Guan1, Yuan Zou1, Mingxia Zhang1, Jiangquan Lv1, Huali Shen2, Pengyuan Yang2, Huimin
Zhanga1, Zhi Zhu1, Chaoyong James Yang1*
1: State Key Laboratory of Physical Chemistry of Solid Surfaces, the Key Laboratory for Chemical
Biology of Fujian Province, The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation,
Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University,
Xiamen 361005, P. R. China
2: Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai
200433, China.
E-mail: cyyang@xmu.edu.cn
S1
FIG S1. Influence of fluorinated oil GH-135 and E2K0660 to the activity of β-Gal. A negative control
sample containing no β-Gal, a positive control with β-Gal in water phase, and a droplet group with βGal in W/O droplets were prepared and the enzyme activity of each group was recorded.
Fluorescent intensity
120
100
80
60
40
20
0
20
40
60
80
100
120
Incubation Time/min
FIG S2. Representative time traces of enzyme activity measured in microfluidic droplets under single-molecule condition.
S2
Table S1. Fluorescence intensity distribution for different β-Gal concentrations (1000 droplets
for each experiment)
Input concentration
(fM)
54
270
540
Observed cpd
Measured
ratio
%
Theoretical
ratio
%
0
92.0
90.5
≥1
8.0
9.5
0
58.6
60.6
1
32.1
30.3
≥2
9.3
9.1
0
40.2
36.8
1
39.8
36.8
2
14.3
18.4
≥3
5.7
8.0
χ2
P value
2.6
>0.05
1.7
>0.05
21.3
<0.05
Table S2. Distribution of “bright” and “dark” droplets for different β-Gal concentrations (1000
droplets for each experiment)
Input concentration
(fM)
54
270
540
Observed cpd
Measured
ratio
%
Theoretical
ratio
%
0
92.0
90.5
≥1
8.0
9.5
0
58.6
60.6
≥1
41.4
39.4
0
40.2
36.8
≥1
59.8
63.2
χ2
P value
2.6
>0.05
1.67
>0.05
5.0
<0.05
S3