Journal article
Functionalization of SU-8 Photoresist Surfaces with IgG Proteins
Nanoprobes Group, NanoSystemsEngineering Section, Department of Micro- and Nanotechnology, Technical University of Denmark1
NanoSystemsEngineering Section, Department of Micro- and Nanotechnology, Technical University of Denmark2
Department of Micro- and Nanotechnology, Technical University of Denmark3
Fluidic Array Systems and Technology Group, Biomedical Micro Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark4
Biomedical Micro Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark5
The negative epoxy-based photoresist SU-8 has a variety of applications within microelectromechanical systems (MEMS) and lab-on-a-chip systems. Here, several methods to functionalize SU-8 surfaces with IgG proteins were investigated. Fluorescent labeled proteins and fluorescent sandwich immunoassays were employed to characterize the binding efficiency of model proteins to bare SU-8 surface, SU-8 treated with cerium ammonium nitrate (CAN) etchant and CAN treated surfaces modified by aminosilanization.
The highest binding capacity of antibodies was observed on bare SU-8. This explains why bare SU-8 in a functional fluorescent sandwich immunoassay detecting C-reactive protein (CRP) gave twice as high signal as compared with the other two surfaces. Immunoassays performed on bare SU-8 and CAN treated SU-8 resulted in detection limits of CRP of 30 and 80 ng/ml respectively which is sufficient for detecting CRP in clinical samples, where concentrations of 3–10 μg/ml are normal for healthy individuals.
In conclusion, bare SU-8 and etched SU-8 can be modified with antibodies by a simple adsorption procedure which simplifies building lab-on-a-chip systems in SU-8. Additionally, we report the fabrication process and use of microwells created in a SU-8 layer with the same dimensions as a standard microscope glass slide that could fit into fluorescent scanners.
The SU-8 microwells minimize the reagent consumption and are straightforward to handle compared to SU-8 coated microscope slides.
Language: | English |
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Year: | 2008 |
Pages: | 2896-2902 |
ISSN: | 18735584 and 01694332 |
Types: | Journal article |
DOI: | 10.1016/j.apsusc.2008.08.089 |
ORCIDs: | Keller, Stephan Urs , Boisen, Anja and Dufva, Hans Martin |