Kinetics of Immunolatex Deposition at Abiotic Surfaces under Flow Conditions: Towards Quantitative Agglutination Assays

Abstract

Physicochemical properties of immunolatex, prepared by incubation of negatively charged polystyrene microparticles with polyclonal rabbit IgGs, were determined by a variety of experimental techniques. These comprised dynamic light scattering (DLS), laser Doppler velocimetry (LDV) and atomic force microscopy (AFM). The particle diffusion coefficient, the hydrodynamic diameter, the electrophoretic mobility, the zeta potential and the suspension stability were determined as a function of pH for different ionic strengths. The deposition of the immunolatex on bare and polyallylamine (PAH) functionalized mica was investigated using the microfluidic oblique impinging-jet cell, with an in situ, real-time image analysis module. The particle deposition kinetics was acquired by a direct particle enumeration procedure. The measurements enabled us to determine the range of pH where the specific deposition of the immunolatex on these substrates was absent. We argue that the obtained results have practical significance for conducting efficient flow immunoassays governed by specific antigen/antibody interactions.

Mechanism of Anti-Salmonella Rabbit Immunoglobulin Adsorption on Polymer Particles

“…The electrokinetic properties of the immunolatex obtained in our work were compared with the ones previously determined for monoclonal immunoglobulin (anti-fibrinogen) [ 23 ] and the commercial immunolatex of BIOMEX, previously studied in Ref. [ 24 ] and referred to as SAL. This latex was prepared by the incubation of the polymer particles with IgaR solution of the concentration a 40 times larger than in our study.…”

“… Zeta potential of various immunolatexes vs. pH determined at 10 mM NaCl. ( ▲ ) previous results for mouse monoclonal IgGs, ( ● ) the IgaR immunolatex (this work, immunoglobulin coverage 2.8 mg m −2 , adsorption at pH 3.5), (■) the SAL latex commercial product of BIOMEX [ 24 ]. The solid lines are guides for the eyes.…”

“…Therefore, the mechanism of the antibody monolayer (corona) formation on polystyrene microparticles remains rather obscure. As a result, the commercially implemented procedures of immunolatex preparation are rather intuitive, consisting in a prolonged incubation of the polystyrene microparticles with immunoglobulins of excessive concentrations, followed by a blocking step involving solutions of albumins, commonly bovine serum albumin [ 7 , 10 , 24 ]. However, such procedures have several drawbacks.…”

Materials for Infectious Diseases

“…In the context of diagnoses, there are papers, such as the research conducted by Adamczyk et al, which describe the importance of investigating the mechanism of the “non-specific adsorption of immunolatex particles at solid substrates” with different charges. This study could be useful for designing more efficient biosensors [ 4 ]. As a point-of-care sensor to detect dilute biomarkers, Edwards and colleagues fabricated an optical protease sensor based on peptide–cellulose conjugates.…”