Novel epoxy-silica nanoparticles to develop non-enzymatic colorimetric probe for analytical immuno/bioassays

Chandra K Dixit; Snehasis Bhakta; John Macharia; Jared Furtado; Steven L Suib; James F Rusling

doi:10.1016/j.aca.2018.04.044

Novel epoxy-silica nanoparticles to develop non-enzymatic colorimetric probe for analytical immuno/bioassays

Anal Chim Acta. 2018 Oct 22:1028:77-85. doi: 10.1016/j.aca.2018.04.044. Epub 2018 Apr 24.

Authors

Chandra K Dixit¹, Snehasis Bhakta², John Macharia², Jared Furtado², Steven L Suib³, James F Rusling⁴

Affiliations

¹ Department of Chemistry, University of Connecticut, Storrs, CT, 06269-3060, USA. Electronic address: chandrakumar.dixit@gmail.com.
² Department of Chemistry, University of Connecticut, Storrs, CT, 06269-3060, USA.
³ Department of Chemistry, University of Connecticut, Storrs, CT, 06269-3060, USA; Institute of Materials Science, University of Connecticut, Storrs, CT, 06269-3136, USA.
⁴ Department of Chemistry, University of Connecticut, Storrs, CT, 06269-3060, USA; Institute of Materials Science, University of Connecticut, Storrs, CT, 06269-3136, USA; Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA; School of Chemistry, National University of Ireland at Galway, Galway, Ireland.

Abstract

We have developed a novel method to develop epoxy silica nanoparticles (EfSiNP) in a single pot. High surface coverage of epoxy functional groups between 150 and 57000 molecules per particles (∼10¹³-10¹⁶ molecules/mL of 200 nm EfSiNPs) was achieved for different preparation conditions. We then created a red colored probe by conjugating Fuchsin dye to the epoxy functionalities of EfSINPs. Anti-mouse IgG was co-immobilized with Fuchsin and their ratios were optimized for achieving optimum ratios by testing those in functional assays. Dye to antibody ratios were in good negative correlation with a coefficient of -1.00 measured at a confidence level of over 99%. We employed the developed non-enzymatic colorimetric immunonanoprobe for detecting mouse IgG in a direct immunoassay format. We achieved a sensitivity of 427 pg/mL with the assay.

Keywords: Antibody; Conjugation; Crosslinking; Epoxysilane; Fuchsin; Silica nanoparticles; Tetraethylorthosilicate.

MeSH terms

Biological Assay / methods*
Colorimetry / methods*
Epoxy Compounds / chemistry*
Immunoassay / methods*
Nanoparticles / chemistry*
Silicon Dioxide / chemistry*

Substances

Epoxy Compounds
Silicon Dioxide

Grants and funding

R01 EB016707/EB/NIBIB NIH HHS/United States