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

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 (∼10-10 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.

Preparation, Characterization and Adsorption into Aqueous Solutions of Polyethyleneimine-Coated Silica Nanoparticles

“…The procedure for the functionalization of the silicas with epoxy groups was adapted in a similar fashion to that of the procedures in the literature (28)(29)(30). Prior to use, AEROSIL ® 200 nanoparticles were firstly dried in a vacuum drying oven at 150 °C for 24 hours.…”

Enhancement of Sensitivity for Retroreflection‐Based Biosensor by Controlling Polymer Brush on Janus Particles

“…Several studies have adopted silane functional groups as linker moieties for bio-substance. [29][30][31][32][33] Smaller particles are beneficial because of their large surface area, resulting in a large number of surface functional groups; however, optical recognition becomes difficult. Another possible method is to increase the number of surface functional groups by anchoring polymeric chain on the surfaces.…”

Silica Nanoparticles Synthesized from 3,3,3-Propyl(trifluoro)trimethoxysilane or n-Propyltrimethoxysilane for Creating Superhydrophobic Surfaces

“…12,13 This method has been extended to a single-pot synthesis of a TEOS core NP followed by continued growth through the introduction of epoxy silane, resulting in a composite NP with epoxy silane surface chemistry. 16 Here, the use of a single hydrophobic precursor ensures a 1:1 stoichiometry of hydrophobic functionality to Si, which is not possible in the conventional synthesis of SHS NPs by a two-step process of silica NP synthesis followed by coating with a hydrophobic alkyl-or fluoroalkylsilane. This high degree of hydrophobic functionality is reflected in water contact angles above 160°for thin films of the alkyl-and fluoro-NPs.…”

“…The sol–gel synthesis generally follows the Stöber method where alkoxysilanes such as tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS) undergo stepwise hydrolysis and polycondensation to form colloids . The Stöber method has been tuned through modifications to silane concentrations, solvent conditions, catalysts, and temperatures to better control silica NP growth and the resulting particle sizes. − Alkoxysilanes with various organo-functionalities are also used to modify silica NP properties by cocondensing them with a core silane precursor as well as postfunctionalizing them on presynthesized silica NPs to produce ORMOSILs. − …”

“…The acid hydrolysis step allows for a complete solubilization of the precursor but requires a base catalyst. Dixit et al demonstrated an elegant approach using just a base catalyst in a water/alcohol solvent in which they eliminated unreacted TEOS precursor using a “phasing out” emulsification process in water. , This method has been extended to a single-pot synthesis of a TEOS core NP followed by continued growth through the introduction of epoxy silane, resulting in a composite NP with epoxy silane surface chemistry . Here, the use of a single hydrophobic precursor ensures a 1:1 stoichiometry of hydrophobic functionality to Si, which is not possible in the conventional synthesis of SHS NPs by a two-step process of silica NP synthesis followed by coating with a hydrophobic alkyl- or fluoroalkylsilane.…”