Controlled Film Architectures to Detect a Biomarker for Pancreatic Cancer Using Impedance Spectroscopy

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• 作者：Andrey C. Soares ; Juliana C. Soares ; Flavio M. Shimizu ; Matias E. Melendez ; Andr茅 L. Carvalho ; Osvaldo N. Oliveira Jr.
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：7
• 期：46
• 页码：25930-25937
• 全文大小：528K
• ISSN：1944-8252

文摘

The need for analytical devices for detecting cancer at early stages has motivated research into nanomaterials where synergy is sought to achieve high sensitivity and selectivity in low-cost biosensors. In this study, we developed a film architecture combining self-assembled monolayer (SAM) and layer-by-layer (LbL) films of polysaccharide chitosan and the protein concanavalin A, on which a layer of anti-CA19鈥? antibody was adsorbed. Using impedance spectroscopy with this biosensor, we were capable of detecting low concentrations of the antigen CA19鈥?, an important biomarker for pancreatic cancer. The limit of detection of 0.69U/mL reached is sufficient for detecting pancreatic cancer at very early stages. The selectivity of the biosensor was inferred from a series of control experiments with samples of cell lines that were tested positive (HT29) and negative (SW620) for the biomarker CA19鈥?, in addition to the lack of changes in the capacitance value for other analytes and antigen that are not related to this type of cancer. The high sensitivity and selectivity are ascribed to the very specific antigen鈥揳ntibody interaction, which was confirmed with PM-IRRAS and atomic force microscopy. Also significant is that used information visualization methods to show that different cell lines and commercial samples containing distinct concentrations of CA19鈥? and other analytes can be easily distinguished from each other. These computational methods are generic and may be used in optimization procedures to tailor biosensors for specific purposes, as we demonstrated here by comparing the performance of two film architectures in which the concentration of chitosan was varied.