Abstract
It is highly desirable to develop a rapid and simple method to detect pathogens. Combining nanomaterials with electrochemical techniques is an efficient way for pathogen detection. Herein, a novel 3D Ag nanoflower was prepared via a biomineralization method by using bovine serum albumin (BSA) as a template. It was adopted as a sensing interface to construct an electrochemical bacteria immunosensor for the rapid detection of foodborne pathogens Escherichia coli (E. coli) O157:H7. Bacterial antibody was immobilized onto the surface of Ag nanoflowers through covalent conjugation. Electrochemical impedance spectroscopy (EIS) was used to detect and validate the resistance changes, where [Fe(CN)6]3−/4− acted as the redox probe. A linear relation between R et and E. coli concentration was obtained in the E. coli concentration range of 3.0 × 102–3.0 × 108 cfu mL−1. The as-prepared biosensor gave rise to an obvious response to E. coli but had no distinct response to Cronobacter sakazakii, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus albus, Lactobacillus easei, and Shigella flexneri, revealing a high selectivity for the detection of the pathogens down to 100 cfu mL−1 in a short time. We believe that this BSA-conjugated 3D Ag nanoflowers could be used as a powerful interface material with good conductivity and biocompatibility for improving pathogen detection and treatment in the field of medicine, environment, and food safety.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1711-3) contains supplementary material, which is available to authorized users.
Highlights
The risk being infected by pathogenic bacteria in food and drinking water is one of the major concerns on human health
The petals on the Ag nanoflower surfaces stretched to different directions, which had a thickness of ca. 10 nm
The results suggested that the total numbers of encapsulated E. coli would increase followed by an increased antibody concentration, actions which would significantly influence the redox probe penetration level
Summary
The risk being infected by pathogenic bacteria in food and drinking water is one of the major concerns on human health. A great number of nanomaterials including noble metal nanoparticles, quantum dots, and carbon nanomaterials as well as metal oxide nanoparticles have been actively explored for the detection of pathogenic bacteria [2,3,4]. Taking advantage of their unusual attributes, such as. The output signal is electrical current, whose intensity is a function of frequency [9], with a Nyquist impedance graph commonly used to determine the electron transfer resistance, Ret. When bacteria affix to an electrode surface, they reduce the output current and increase the impedance of the interface. The interface material should possess good conductivity, which could accelerate the electron transfer; on the other hand, it should afford a highly stable and biocompatible matrix, which is fit for the attachment and growth of cells [12]
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