Detection of Proteins Using Nano Magnetic Particle Accumulation-Based Signal Amplification
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Date
2016
Authors
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Publisher
MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND
Abstract
We report a biosensing method based on magnetic particles where coated magnetic particles are used for immunomagnetic separation, and uncoated magnetic particles are used for signal enhancement. To quantify the signal amplification, optical micrographs are analyzed to measure changes in pixel area and pixel intensity. Microcontact-printed surface receptors are arranged in alternating lines on gold chips, enabling differential calculations. In a model experiment, target molecules-streptavidin-are first captured and separated by biotin-coated magnetic particles, and then exposed to a gold surface functionalized with biotin-coupled bovine serum albumin, forming a sandwich assay. Applying a magnetic field and introducing uncoated magnetic particles resulted in accumulation around magnetic particles in the sandwich assay and enhancement of the contrast to noise ratio at least by eight-fold in a range of 0.1-100 mu M.
Description
Authors acknowledge The Scientific and Technological Research Council of Turkey (TUB ITAK) (Project No.: 114E886) and Abdullah Gul University Scientific Research Program (AGU BAP) (2015-11) for financial support. Authors thank to Cagri Savran and Chun-Li Chang from Purdue University for the fabrication of PDMS stamps and Omary Mzava acknowledges TUBITAK for the scholarship (2215).
Keywords
magnetic nano particle, magnetic accumulation, contrast-to-noise ratio, micro contact printing, biosensing, signal amplification