Fabrication and characterization of tosyl‐activated magnetic and nonmagnetic monodisperse microspheres for use in microfluic‐based ferritin immunoassay

Abstract

This article describes the preparation of tosyl-activated nonmagnetic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) [P(HEMA-GMA)] microspheres by dispersion polymerization and tosyl-activated magnetic poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) [P(HEMA-EDMA)] microspheres by multistep swelling polymerization method and precipitation of iron oxide inside the pores. These new approaches show that monodisperse microspheres, 2.3 µm, respectively 4.1 µm, in diameter can be produced in high yields avoiding aggregation and with the advantage of being free of aromatic moieties. To demonstrate their potential for diagnostic applications, both types of microparticles have been coated with capture and detection antibodies (DAs), respectively. Immunoassay protocols have then been developed for the dosage of ferritin using an automated affinity platform combining microchannel chips and electrochemical detection. The assay performance using the above magnetic microspheres has been compared with that obtained with commercial tosyl-activated beads. Finally, the possibility to combine functionalized magnetic and nonmagnetic microspheres has been evaluated in view of amplifying the number of enzymatic labels in the immuno-complex. At a ferritin concentration of 119.6 ng/mL, a signal-to-noise ratio of 150.5 is obtained using 0.2 mg/mL of anti-ferritin-coated P(HEMA-GMA)-DA microspheres against a value of 158.8 using free DA in solution.

Investigation of chemical modification on tosyl-activated polystyrene microsphere magnetic particle surface by infrared microscopy

“…Various polymerimmobilizations to particle surfaces, have been reported in order to achieve biological goals. 3,[11][12][13][14][15][16][17] The advantage of attaching amino-dextran to micro/nanoparticles for ATPS is to give the target particles more affinity to dextran-rich phase, which is located at the bottom of two layers (The top layer of ATPS, PEG-rich phase is more hydrophobic. Also the bottom layer, DEX-rich phase is more hydrophilic and dense).…”

“…6,7 Wide and various applications on IR spectroscopy cover even the confirmation of bacterial attachment and changes on particles 3,8,9 and IR spectroscopy is still considered as one of the most widely used and reliable methods for chemical changes at the surface of materials. 3,6,7,[10][11][12][13][14][15]17,18 Here the infrared (IR) microscopic investigation results to prove the surface modification of polystyrene (PS)-coated magnetic microparticles, are reported. .…”

Use of specific polysaccharide‐immobilized monodisperse poly(glycidyl methacrylate) core–silica shell microspheres for affinity purification of lectins

“…PGMA microspheres are of growing interest for various biotechnological applications (Reymond et al ., ). They were successfully used for immobilization of α ‐amylase (He et al ., ) and catalase (Bayramoglu et al ., ), as well as enzyme stabilization (Milosavić and Prodanović, ), for binding of hemoglobin from human blood hemolysate (Altıntas et al ., ), adsorption and separation of immunoglobulins (Bayramoglu et al ., ), and ion exchange chromatographic separation of other proteins (Unsal et al ., ).…”

Microfluidic-Based Electrochemical Immunosensing of Ferritin

“…The work by Reymond et al on a microfluidic-based ferritin immunoassay used an eight channel electrochemical microchip modified with magnetic and non-magnetic microspheres for antibody immobilization. However, the research did not cover the required clinical range of ferritin quantification [43]. In another article by Song et al, the use of cotton thread as a microfluidic circuit was suggested, where three sets of antibodies were used in the sensor fabrication.…”