Dextran-coated nanoparticles as immunosensing platforms: Consideration of polyaldehyde density, nanoparticle size and functionality



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Gao, Shipeng and Torrente Rodríguez, Rebeca M. and Pedrero Muñoz, María and Pingarrón Carrazón, José Manuel and Campuzano Ruiz, Susana and Rocha Martin, Javier and Guisán, José M. (2022) Dextran-coated nanoparticles as immunosensing platforms: Consideration of polyaldehyde density, nanoparticle size and functionality. Talanta, 247 . p. 123549. ISSN 0039-9140

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Magnetic nanoparticles (MNPs) can be used as antibody carriers in a wide range of immunosensing applications. The conjugation chemistry for preparing antibody-MNP bionanohybrids should assure the nanoparticle’s colloidal dispersity, directional conformation and high biofunctionality retention of attached antibodies. In this work, peroxidase (HRP) was selected as model target analyte, and stable antibody-MNP conjugates were prepared using polyaldehyde-dextrans as multivalent linkers, also to prevent nanoparticles agglomeration and steric shielding of non-specific proteins. Under the manipulation of the oxidation variables, MNP-conjugated antibody showed the highest Fab accessibility, of 1.32 μmol analyte per μmol antibody, corresponding to 139 μmol aldehyde per gram of nanocarrier (5 mM NaIO4, 4 h). Demonstrating anti-interference advantage up to 10% serum, colorimetric immunoassay gave a detection limit (LOD) of 300 ng mL− 1 , while electrochemical transduction led to a considerable (680 times) improvement, with a LOD of 0.44 ng mL− 1 . In addition, polyaldehydedextran showed priority over polycarboxylated-dextran as the multivalent antibody crosslinker for MNPs in terms of sensitivity and LOD value, while immunosensors constructed with carboxylated magnetic microbeads (HOOC-MBs) outperformed MNPs-based immunoplatforms. This work sheds light on the importance of surface chemistry (type and density of functional groups) and the dimension (nanosize vs micrometer) of magnetic carriers to conjugate antibodies with better directional orientation and improve the analytical performance of the resulting immunosensors.

Item Type:Article
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CRUE-CSIC (Acuerdos Transformativos 2022)

Uncontrolled Keywords:Iron oxide nanoparticles; Dextran-coated nanoparticles; Antibody orientation; Immunosensors
Subjects:Sciences > Chemistry > Biochemistry
Sciences > Chemistry > Analytic chemistry
Medical sciences > Biology > Biotechnology
ID Code:72449
Deposited On:24 May 2022 08:01
Last Modified:24 May 2022 11:33

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