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Dextran-coated nanoparticles as immunosensing platforms: Consideration of polyaldehyde density, nanoparticle size and
Shipeng Gao1, Rebeca M Torrente-Rodríguez2, María Pedrero2
1Department of Biocatalysis. Institute of Catalysis and Petrochemistry, ICP/CSIC, Campus UAM, Cantoblanco, 28049, Madrid, Spain.
Talanta
|May 24, 2022
Summary
Stable antibody-magnetic nanoparticle (MNP) conjugates were created using polyaldehyde-dextrans. Electrochemical immunosensors using these MNP-antibody conjugates achieved a low limit of detection for peroxidase, outperforming other methods.
Area of Science:
- Nanotechnology
- Bioconjugation Chemistry
- Immunosensing
Background:
- Magnetic nanoparticles (MNPs) are versatile carriers for antibodies in immunosensing.
- Effective antibody conjugation to MNPs requires maintaining nanoparticle dispersity, antibody orientation, and biofunctionality.
Purpose of the Study:
- To develop stable antibody-MNP conjugates using polyaldehyde-dextrans as linkers.
- To optimize conjugation chemistry for enhanced antibody accessibility and immunosensor performance.
- To compare MNP-based immunosensors with microbead-based ones and evaluate linker strategies.
Main Methods:
- Preparation of antibody-MNP bionanohybrids using polyaldehyde-dextrans.
- Optimization of oxidation variables for maximal Fab accessibility.
- Fabrication and testing of colorimetric and electrochemical immunosensors.
- Comparison of polyaldehyde-dextran and polycarboxylated-dextran linkers.
- Evaluation of MNPs versus magnetic microbeads (MBs).
Main Results:
- Optimal MNP-conjugated antibody showed high Fab accessibility (1.32 μmol analyte/μmol antibody).
- Electrochemical immunosensors achieved a low limit of detection (LOD) of 0.44 ng mL⁻¹, 680 times better than colorimetric assays (300 ng mL⁻¹).
- Polyaldehyde-dextran linkers outperformed polycarboxylated-dextran, and microbead-based immunosensors showed superior performance to MNP-based ones.
Conclusions:
- Surface chemistry and carrier dimension significantly impact antibody orientation and immunosensor analytical performance.
- Polyaldehyde-dextran is a superior linker for antibody-MNP conjugation compared to polycarboxylated-dextran.
- Microbead-based immunosensors offer advantages over nanoparticle-based platforms for this application.
