Label-Free Electrochemical Aptasensor Based on the Vertically-Aligned Mesoporous Silica Films for Determination of Aflatoxin B1

Herein we report a highly specific electrochemical aptasenseor for AFB1 determination based on AFB1-controlled diffusion of redox probe (Ru(NH3)(6)(3+)) through nanochannels of AFB1-specific aptamer functionalized VMSF. A high density of silanol groups on the inner surface confers VMSF with cationic permselectivity, enabling electrostatic preconcentration of Ru(NH3)(6)(3+) and producing amplified electrochemical signals. Upon the addition of AFB1, the specific interaction between the aptamer and AFB1 occurs and generates steric hindrance effect on the access of Ru(NH3)(6)(3+), finally resulting in the reduced electrochemical responses and allowing the quantitative determination of AFB1. The proposed electrochemical aptasensor shows excellent detection performance in the range of 3 pg/mL to 3 & mu;g/mL with a low detection limit of 2.3 pg/mL for AFB1 detection. Practical analysis of AFB1 in peanut and corn samples is also accomplished with satisfactory results by our fabricated electrochemical aptasensor.