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Rapid Homogeneous Detection of Biological Assays Using Magnetic Modulation Biosensing System
Published on: June 13, 2010
Robust immunosensing system based on biotin-streptavidin coupling for spatially localized femtogram mL-1 level
Kaixin Zhang1, Guozhen Liu2, Ewa M Goldys1
1ARC Centre of Excellence for Nanoscale Biophotonics (CNBP), Macquarie University, North Ryde 2109, Australia.
Insights
This study presents an ultrasensitive optical fiber sensor for detecting interleukin-6 (IL-6) at femtogram levels in biological samples. The novel sensor achieves high sensitivity and spatial localization, offering a promising tool for biomedical research.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Biotechnology
Background:
- Accurate detection of low cytokine concentrations, like interleukin-6 (IL-6), is crucial for biomedical research and clinical diagnostics.
- Existing methods may lack the sensitivity or spatial resolution required for certain applications.
Purpose of the Study:
- To develop an ultrasensitive, spatially-localized optical fiber sensor for detecting interleukin-6 (IL-6).
- To validate the sensor's performance in biological matrices like serum and cell culture media.
Main Methods:
- Fabrication of a sandwich immunosensor on an optical fiber surface using biotin-streptavidin coupling for antibody immobilization.
- Utilizing fluorescent magnetic nanoparticles for signal detection of captured IL-6.
- Demonstrating localized detection with a spatial resolution of 200µm and a sample volume of 1µL.
Main Results:
- Achieved ultrasensitive detection of IL-6 down to 0.1 pg/mL, with a linear range from 0.4 pg/mL to 400 pg/mL.
- Successfully demonstrated spatially-localized detection of IL-6 in serum and cell culture media.
- The sensor's performance was comparable to the conventional enzyme-linked immunosorbent assay (ELISA) for detecting IL-6 secreted by BV-2 cells.
Conclusions:
- The developed optical fiber sensor provides ultrasensitive and spatially-localized detection of IL-6.
- This technology holds significant potential for advancing biomedical research and clinical applications requiring precise cytokine quantification.
Abstract:
Detection of a very low amount of cytokines such as interleukin-6 (IL-6) in clinical fluids is important in biomedical research and clinical applications. Here, we demonstrate spatially-localized ultrasensitive (femtogram mL-1) level detection of IL-6 in serum and in cell culture media. Our approach is based on a sandwich immunosensor fabricated on the surface of an optical fibre. Firstly, the biotinylated IL-6 capture antibody was immobilized on the fibre surface by biotin-streptavidin coupling. Then the fabricated fibre was used for capturing IL-6 followed by exposure to detection antibody which was labeled with the fluorescent magnetic nanoparticles to report the signal. A linear relationship between IL-6 concentration and the fluorescence signal was obtained in the range from 0.4pgmL-1 to 400pgmL-1 of IL-6, with the limit of detection down to 0.1pgmL-1. In addition, this optical fibre sensor was successfully applied for the localized detection of IL-6 with the spatial resolution of 200µm and a sample volume of 1µL. Finally, the performance of the fibre sensor was demonstrated by detection of IL-6 secreted by BV-2 cells with comparable performance of the conventional enzyme-linked immunosorbent assay (ELISA).
