Abstract
In this work, an electrochemical paper-based aptasensor was fabricated for label-free and ultrasensitive detection of epidermal growth factor receptor (EGFR) by employing anti-EGFR aptamers as the bio-recognition element. The device used the concept of paper-folding, or origami, to serve as a valve between sample introduction and detection, so reducing sampling volumes and improving operation convenience. Amino-functionalized graphene (NH2-GO)/thionine (THI)/gold particle (AuNP) nanocomposites were used to modify the working electrode not only to generate the electrochemical signals, but also to provide an environment conducive to aptamer immobilization. Electrochemical characterization revealed that the formation of an insulating aptamer–antigen immunocomplex would hinder electron transfer from the sample medium to the working electrode, thus resulting in a lower signal. The experimental results showed that the proposed aptasensor exhibited a linear range from 0.05 to 200 ngmL−1 (R2 = 0.989) and a detection limit of 5 pgmL−1 for EGFR. The analytical reliability of the proposed paper-based aptasensor was further investigated by analyzing serum samples, showing good agreement with the gold-standard enzyme-linked immunosorbent assay.
Highlights
Epidermal growth factor receptor (EGFR), with tyrosine kinase activity, is a transmembrane glycoprotein[1,2]
The normal EGFR concentration in humans is in the range of 1–25 ngml−1; overexpression of EGFR occurs in a variety of carcinomas, including gastric, breast, ovarian, and colorectal cancers[5]
Once a sample was added from the sample inlet, it would flow through the microchannel and permeate to the surface of the working electrode (WE) to enable electrochemical detection
Summary
Epidermal growth factor receptor (EGFR), with tyrosine kinase activity, is a transmembrane glycoprotein[1,2]. The concentration of EGFR in the lymph node metastasis of lung cancer patients can be as high as 850 ngml−1 Atkins et al used an IHC-based screening method for the detection of EGFR with the EGFR pharmDX kit[11]. These techniques face challenges ranging from their detection ranges, sensitivities, assay complexity to the cost of equipment[12,13]. To overcome these limitations, electrochemical detection methods have been developed for the quantitative detection of EGFR. Ilkhani et al reported a new electrochemical aptamer/antibodybased sandwich immunosensor with a linear sensing
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