Production of hybrid iron-carbon ultradispersed particles and their application in immunoassay

Abstract

Highly dispersed materials are a sought-after component in a variety of analytical systems. Forming nanoparticles from multiple components allows for the combination of their properties, thereby increasing the efficiency of analytical applications. This paper presents work on the production of a new type of such particles, consisting of iron oxide and carbon components, and the evaluation of their effectiveness in immunochromatography. The components of this preparation provide magnetic properties for separation and concentration (iron oxide), as well as intense coloration for highly sensitive detection of labeled specific immune complexes (carbon materials).
The particle synthesis method is based on the thermal decomposition of iron pentacarbonyl in the presence of a suspension of fullerene or carbon nanotubes. Conducting the reaction in an anhydrous medium (dimethyl sulfoxide:toluene = 1:1) produces a highly dispersed. The average diameter of the resulting particles, according to transmission electron microscopy and dynamic light scattering, is approximately 400 nm. Transfer to an aqueous medium is accompanied by particle aggregation. To stabilize the particles, their surfaces were silanized using a comparison of tetraethoxysilane, aminopropyltriethoxysilane, and trimercaptopropyltrimethoxysilane as reagents. Tetraethoxysilane provided the most effective stabilization. The particles modified with it remained stable in aqueous solutions; their average diameter was 430 nm. Spectral characterization confirmed the success of incorporating carbon components to increase the extinction coefficient.
An immunochromatographic test system for the detection of the antibiotic tiamulin in meat was developed using the obtained particles. The particles were functionalized by adsorption of monoclonal antibodies in the presence of a blocking agent. Assay conditions ensuring minimum detection limits were established. Without preconcentration, the visual limit of colorimetric detection of tiamulin was 60 pg/mL, while with magnetic preconcentration, it was reduced by 50-fold, significantly outperforming alternative methods.
This work was supported by the Russian Science Foundation (grant no. 24-16-00273).

Speaker

Taranova Nadezhda
A.N. Bach Institute of Biochemistry, Centre of Biotechnology of the Russian Acad. Sci.
Russia

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