Abstract

An Aflatoxin B1 (AFB1) biosensor was fabricated via an Ag nanoparticles assembly on the surface of a porous anodized aluminum (PAA) membrane. First, the Raman reporter 4-Aminothiophenol (4-ATP) and DNA (partially complementary to AFB1 aptamer) were attached to the surface of Ag nanoparticles (AgNPs) by chemical bonding to form a 4-ATP-AgNPs-DNA complex. Similarly, the surface of a PAA membrane was functionalized with an AFB1 aptamer. Then, the PAA surface was functionalized with 4-ATP-AgNPs-DNA through base complementary pairing to form AgNPs-PAA sensor with a strong Raman signal. When AFB1 was added, AgNPs would be detached from the PAA surface because of the specific binding between AFB1 and the aptamer, resulting in a reduction in Raman signals. The detection limit of the proposed biosensor is 0.009 ng/mL in actual walnut and the linear range is 0.01–10 ng/mL. The sensor has good selectivity and repeatability; it can be applied to the rapid qualitative and quantitative detection of AFB1.

Highlights

  • Aflatoxins are listed as Class I carcinogen by the World Health Organization [1]

  • To investigate whether the Ag nanoparticles (AgNPs)-porous anodized aluminum (PAA) sensor can be used for Aflatoxin B1 (AFB1) detection, the AgNPs-PAA

  • To study the repeatability of the sensor, the same batch of 30 AgNPs-PAA biosensors were soaked in 0.1 ng/mL AFB1 spiked walnut sample for 2 h in the dark, washed with water and dried at room temperature

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Summary

Introduction

Aflatoxins are listed as Class I carcinogen by the World Health Organization [1]. Among them, Aflatoxin B1 (AFB1 ) has increasingly attracted public attention because of its strongest toxic effect and high carcinogenicity [2,3,4]. Surface-enhanced Raman scattering (SERS) has been applied in many fields [14], such as food chemistry [15,16,17], environmental science [18], and biotechnology [19,20,21]. A popular SERS substrate consists of noble metallic nanostructures, which can sustain surface plasmon resonance and enhancing the reports detection. Ag nanoparticles (AgNPs) are a common substrate due to its gold nanostar core–Ag nanoparticle satellite sensor can be used to detect AFB1 content in peanutsimple milk. Solution.If As a typical example surface mechanical stability and easy preparation a PAA membrane is of a biosensor, a porous anodized aluminum membraneofhas characteristic features and of a combined with SERS technology, it can prevent(PAA). Schematic illustration of the fabrication of Surface-enhanced Raman scattering (SERS) active

Reagents and Materials
Instrument
Preparation of 4-ATP-AgNPs-DNA
Preparation and Surface Modification of PAA Membrane
Fabrication of AgNPs-PAA Biosensor
Detection of AFB1 with AgNPs-PAA Biosensor
Detection of Specificity and Repeatability in AgNPs-PAA Biosensor
Representation of Sensors
Selection
When the
Surface-enhanced
Specificity
Conclusions
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