A label‐free protein microfluidic array for parallel immunoassays

Abstract

A label-free protein microfluidic array for immunoassays based on the combination of imaging ellipsometry and an integrated microfluidic system is presented. Proteins can be patterned homogeneously on substrate in array format by the microfluidic system simultaneously. After preparation, the protein array can be packed in the microfluidic system which is full of buffer so that proteins are not exposed to denaturing conditions. With simple microfluidic channel junction, the protein microfluidic array can be used in serial or parallel format to analyze single or multiple samples simultaneously. Imaging ellipsometry is used for the protein array reading with a label-free format. The biological and medical applications of the label-free protein microfluidic array are demonstrated by screening for antibody-antigen interactions, measuring the concentration of the protein solution and detecting five markers of hepatitis B.

A Compact Imaging Ellipsometer for Label-free Biosensor

“…The volume of the compact model is 370×230×110 (mm3).The autocollimator is used simply to locate the sample for test. We use a micro fluidic system of protein microarray [9] to fabricate a sample with 8 protein units in microarray. The fabrication process is as the following:…”

Approach to Quantitative Detection of CD146 with a Label-free Protein Biosensor Based on Imaging Ellipsometry

“…To perform molecular interaction as the high throughput immunoassays, BIE has been developed in our laboratory [5,6,14]. Now, it is mainly composed of a micro-fluidic reactor array system and an imaging ellipsometry reader.…”

“…A micro-fluidic reactor array system including 48 independent flow channels is used to fabricate protein microarray for high throughput detection by a series of continuous processes, including surface patterning, solution delivery, ligand immobilization, blocking, target capture, rinsing, etc [5,6]. The micro-fluidic array system is composed of four main parts: sample reservoir, multi-cell array, multi-channels and pumps.…”

“…Imaging ellipsometry with the advantages of ellipsometry and microscopy simultaneously could measure the surface concentration of protein adsorbing layer accurately without any labeling. It provides possibility to apply BIE's function in a broad range of various biological systems, especially for the detection of protein interactions [5,6]. So far, several bio-targets, such as five markers of Hepatitis B [7], Phage M13KO7 [8], and SARS Virus [9], have been successfully tested with the biosensor.…”

Protein microarray biosensors based on imaging ellipsometry techniques and their applications

“…Over the past 16 years, commercial products based on single wavelength and spectroscopic imaging ellipsometry, made by the Nanofilm Company (http://www.nanofilm.de/; Gedig et al, 2008), have entered the market, and many significant improvements (e.g., the off-null sampling method (Chen et al, 2007a), spectroscopic technique , automatic control, microarray surface modification Jin, 2003a, 2004a, b), micro-fluidic reactors (Jin and Wang, 2002;Wang et al, 2006), bio-system optimization, and protein interaction databases) have been introduced into BIE to improve its performance and feasibility. Therefore, BIE has been developed into an automatic device for quantitative and high-throughput protein analysis ).…”