Campus Units

Mechanical Engineering

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

2018

Journal or Book Title

Analyst

DOI

10.1039/C7AN02039B

Abstract

We demonstrate a sensing mechanism for rapid detection of Listeria monocytogenes in food samples using the actuation of chitosan-aptamer nanobrush borders. The bio-inspired soft material and sensing strategy mimic natural symbiotic systems, where low levels of bacteria are selectively captured from complex matrices. To engineer this biomimetic system, we first develop reduced graphene oxide/nanoplatinum (rGO-nPt) electrodes, and characterize the fundamental electrochemical behavior in the presence and absence of chitosan nanobrushes during actuation (pH-stimulated osmotic swelling). We then characterize the electrochemical behavior of the nanobrush when receptors (antibodies or DNA aptamers) are conjugated to the surface. Finally, we test various techniques to determine the most efficient capture strategy based on nanobrush actuation, and then apply the biosensors in a food product. Maximum cell capture occurs when aptamers conjugated to the nanobrush bind cells in the extended conformation (pH < 6), followed by impedance measurement in the collapsed nanobrush conformation (pH > 6). The aptamer-nanobrush hybrid material was more efficient than the antibody-nanobrush material, which was likely due to the relatively high adsorption capacity for aptamers. The biomimetic material was used to develop a rapid test (17 min) for selectively detecting L. monocytogenes at concentrations ranging from 9 to 107 CFU-mL-1 with no pre-concentration, and in the presence of other gram-positive cells (Listeria innocua and Staphylococcus aureus). Use of this bio-inspired material is among the most efficient for L. monocytogenes sensing to date, and does not require sample pretreatment, making nanobrush borders a promising new material for rapid pathogen detection in food.

Comments

This is a manuscript of the article K. D. Hills, D. A. Oliveira, N. D. Cavallaro, C. L. Gomes and E. S. McLamore, "Actuation of chitosan-aptamer nanobrush borders for pathogen sensing," Analyst, 2018, DOI: 10.1039/C7AN02039B. Posted with permission.

Copyright Owner

Royal Society of Chemistry

Language

en

File Format

application/pdf

Available for download on Friday, March 08, 2019

Published Version

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