Electronic Supplementary Material

Impedimetric aptamer-based determination of the mold toxin fumonisin B1

Xiujuan Chena · Yukun Huanga · Xiaoyuan Maa · Fei Jiab · Xiaofei Guoa · Zhouping Wang a,*

a State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China

b College of Food Science and Nutritional Engineering, China Agriculture and University, Beijing 100083, China

*Corresponding Author, Phone/fax: +86-510-85917023. E-mail:

According to Randles-Sevcik formula, Ip = 2.69×105A•D1/2n3/2V1/2c (Ip is the redox peak current; n is the electron transfer number, n(Fe(CN)63-/4-)=1; c is the concentration of Fe(CN)63-/4- (mol.cm-3); A is the surface area (cm2); D isthe diffusion coefficient of the electrochemical probe (cm2.s-1), D25℃=6.70±0.02×10-6cm2.s-1; v is the scanning speed(V.s-1), v=0.1 V.s-1 in this experiment)[1], the approximate surface area value of AuNP-modified GCE has been calculated as 11.18×10-2 cm2. The surface area of GCE (φ=3 mm) is calculated as 7.068 mm2. The results revealed that the deposited AuNPs increased the active area of the electrode and the amount of immobilized apF10 capture probes.As shown in Fig. S1,current density j (µA.cm-2) of each electrode is used as a function of the potential. It exhibits an increase in the current density jemerging in the AuNPs-deposited GCE (b) compared to bare GCE (a) because of the excellent conductivity of AuNPs, which enhanced the transfer of electrons in the biosensor.Thejvalues decreased when apF10 was self-assembled onto the AuNPs (c) because of the impediment of electron movement in the Fe(CN)63-/4- solution by the negatively charged aptamer.

Fig. S1 The CVs of the stepwise modified electrodes: (a) bare GCE; (b) AuNP-modified GCE; (c) 5’SH-aptamer-AuNP-modified GCE in 5.0 mM K3[Fe(CN)6]: K4[Fe(CN)6] (1:1) mixture containing 0.1 M KCl.

Fig. S2 Nyquist plots of aptamer-based biosensors containing 60 nM FB-1 for different incubation times: (1) 0 min; (2) 5 min; (3) 10 min; (4) 20 min; (5) 30 min; (6) 60 min.

Reference

[1] Bard AJ, Faulkner LR. Electrochemical methods fundamentals and applications. 2nd ed. 2001, Wiley, New York, 1980, p231

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