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A high-performance waveguide-mode biosensor for detection of factor IX using PEG-based blocking agents to suppress
Thangavel Lakshmipriya1, Makoto Fujimaki, Subash C B Gopinath
1Department of Material Science, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan.
The Analyst
|April 12, 2013
Summary
This study introduces an enhanced evanescent-field-coupled waveguide-mode sensor for detecting Factor IX (FIX) protein. A dual polymer strategy significantly boosts sensitivity, enabling precise detection of FIX deficiency in blood samples.
Area of Science:
- Biomedical Engineering
- Biosensing Technology
- Materials Science
Background:
- Evanescent-field-coupled waveguide-mode (EFC-WM) sensors offer label-free detection capabilities.
- Non-specific binding is a major challenge in biosensor sensitivity and reliability.
- Poly(ethylene glycol)-based block copolymers are effective blocking agents in biosensing applications.
Purpose of the Study:
- To develop a highly sensitive biosensor for Factor IX (FIX) protein detection.
- To evaluate the efficacy of poly(ethylene glycol)-based block copolymers as blocking agents.
- To improve the sensitivity and reliability of EFC-WM sensors for clinical diagnostics.
Main Methods:
- Utilized monolithic SiO2/Si/SiO2 sensing plates for EFC-WM sensing.
- Immobilized FIX protein on a glutaraldehyde-modified silica surface, followed by treatment with a biotinylated aptamer.
- Employed streptavidin-conjugated gold nanoparticles (SA-GNPs) for quantitative analysis, with and without N6-PEG modification.
Main Results:
- Poly(ethylene glycol)-b-poly(acrylic acid) (PEG-b-PAAc) effectively masked unreacted moieties, preventing non-specific binding of SA-GNPs.
- Achieved initial sensitivity down to 100 pM for FIX detection.
- N6-PEG modification of SA-GNPs resulted in a 1000-fold sensitivity improvement, reaching 100 fM, confirmed by SEM.
- Demonstrated selective aptamer binding to FIX in complex biological samples.
Conclusions:
- A dual polymer strategy, involving surface blocking and nanoparticle coating, enhances sensor sensitivity and reliability.
- The developed sensor is suitable for detecting FIX deficiency in human blood samples due to its high specificity and sensitivity.
- Further optimization of binding sites on SA-GNPs could potentially improve binding affinity.
