Zwitterion-Coated Colloidal Magnetic Nanoparticle Clusters for Reduced Nonspecific Adsorption of Biomolecules

Abstract

This paper demonstrates fabrication of silica-shell-coated magnetic nanoparticle clusters (SMNCs) and subsequent surface engineering of SMNCs to produce surface-modified SMNCs that have zwitterionic and primary amine ligands (SMNC-ZW/Am). SMNC-ZW/Am was passivated by zwitterionic ligands for improved colloidal stability and reduced nonspecific adsorption and by primary amine ligands for facilitated conjugation with biomolecules. Hydrodynamic (HD) size and zeta potential of SMNC-ZW/Am could be flexibly tuned by controlling the relative amounts of zwitterionic and primary amine ligands. SMNC-ZW/Am had higher colloidal stability in high salt concentration and broad pH range than did bare SMNC. Nonspecific adsorption with biomolecules onto SMNC-ZW/Am surface was significantly suppressed by the zwitterionic ligands. The facile bioconjugation capability of SWNC-ZW/Am enabled conjugation of biotin and antibody to the SWNC-ZW/Am surface. Biomolecule-conjugated SMNC-ZW/Am showed specific binding affinity to streptavidin and Salmonella bacteria, with reduced nonspecific adsorption; therefore, SWMC-ZW/Am has potential use as an antifouling nanosubstrate for separation and bioanalysis.

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“…211 This holds especially true for nanoparticles susceptible to opsonization, meaning to the formation of a protein corona, which can trigger recognition and sequestration by the MPS. To avoid recognition, and extend circulation time, antifouling or hydrophilic polymer, such as polyethylene glycol (PEG) 213 or zwitterionic polymers 214 can be coated onto the surface of the nanoparticles.…”

Magnetic Technologies and Green Solvents in Extraction and Separation of Bioactive Molecules Together with Biochemical Objects: Current Opportunities and Challenges

“…Moreover, magnetic nanoparticles, magnetic nanofluids, magnetic ionic liquids, magnetosome/magnetotactic bacteria, magnetic carbon nanotubes, magnetic polymers, magnetic microcapsules and magnetic restricted access materials have shown great results when used for targeted delivery, controlled release, gene transfection, immunoassays, cell separation and transplantation, protein adsorption and immobilization, tracking of pathogenic microbes, tissue engineering, etc. [12][13][14][15].…”