Electrochemical Olfactory Sensor for Odorants Using Porous Anodic Alumina (PAA) Nanochannels with Coupled Human Odorant Binding Proteins

Abstract

By mimicking biological olifactory systems, sensors have been reported for the identification of important odorants at low concentration levels in complex environments. Herein a rapid and label-free olfactory sensor based on porous anodic alumina (PAA) nanochannels and the human odorant binding protein s(OBP2b) is reported for odorants. The OBP2b proteins were assembled on the surface of the PAA nanochannels by a Schiff base reaction and the recognition and connection of target with the OBP2b proteins led to steric hindrance inside the PAA nanochannels, resulting in a decreased anodic current due to the indicator, potassium ferricyanide. Using the PAA nanochannels with 55 nm pore diameter as the optimal reaction platform and the OBP2b proteins as the recognition element, the chronoamperometry allowed sensitive determination of ethyl acetate, lauric acid, and vanillin. Furthermore, odorants released by fruit samples were also detected by the developed sensor. Consequently, this sensitive and simple strategy provides an efficient and promising approach for environmental and biological sensing.