Electronic Supplementary Material

Simultaneous voltammetric determination of E. coli and S. typhimurium based on target recycling amplification using self-assembled hairpin probes on a gold electrode

Yuna Guoa, Yu Wangb*, Su Liuc, Jinghua Yua, Hongzhi Wanga, Xioakun Liuc, Jiadong Huanga,b

a Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P.R. China

b School of Biological Sciences and Technology, University of Jinan, Jinan 250022, P.R. China

c School of Resources and Environment, University of Jinan, Jinan 250022, P.R. China

* Corresponding author. E-mail: ; Tel.: +86-531-89736122; Fax: +86-531- 82769122

Table S1 Oligonucleotides sequences used in this work.

Oligonucleotide name / sequence (5’ to 3’) description
Escherichia coli O157:H7
rfbE gene / GGCCAAGGATTAGCTGTACAT
HP-MB / SH-AATGTACAGCTAATCCTTGGCCGGTTTGTACATT-MB
Trigger-MB / AATGTACAAACC
Salmonella typhimurium
gyrB gene / AATAAAACGCCGATCCA
HP-Fc / SH-GACACTGGATCGGCGTTTTATTTTAGGAGTGTC-Fc
Trigger-Fc / GACACTCCTA
Listeria monocytogenes
ssrA gene / TCGAACTATCCCTGTCGAAT
Staphylococcus aureus
Nuc gene / GCG ATT GAT GGT GAT ACG GTT

Fig. S1 (A) CVs obtained for the bare Au electrode (a), HPs/Au electrode (b), MCH/HPs/Au electrode (c), MCH/HPs/Au electrode targets after incubated with targets, phi29 and dNTPs (d). Measurements were performed in 10 mM PBS (pH 7.4) containing of 0.25 mM KCl and 5.0 mM K3[Fe(CN)6].

Fig. S2 (A) Effect of the amount of the phi29 DNA polymerase on the MB peak current of biosensor. (B) Effect of the reaction time on the MB peak current of biosensor.


Fig. S3 DPV peak currents responding to PCR products for different concentrations of E. coli O157:H7 and S. Typhimurium.

Table S3 Target DNA analysis in synthetic samples.

Samples (Nos.) / Added (pM) / Found (fM) / Recovery (%)
DNAs / E-DNA / S-DNA / E-DNA / S-DNA
1 / 0.1 / 0.097±0.003 / 0.103±0.004 / 97% / 103%
2 / 0.5 / 0.472±0.013 / 0.511±0.016 / 94.4% / 102.2%
3 / 1.0 / 1.029±0.029 / 0.938±0.031 / 102.9% / 93.8%