Pseudospecific magnetic affinity beads for immunoglobulin-G depletion from human serum

p(HEMA)-RR241 hydrogel membranes with micron network for IgG depletion in proteomic studies

Serum proteins can generally be considered a good source for the illness' indication and are precious resources to detect diseases such as inflammation, cancer, diabetes, malnutrition, cardiovascular diseases, Alzheimer's, other autoimmune diseases, and infections. However, one of the biggest difficulties for proteomic studies is that the majority of serum protein mass consists of only a few proteins. Albumin and Immunoglobulin (IgG) constitute 80% of total serum protein. In this study, dye ligand affinity-based hydrogel membranes were proposed as new materials with micron mesh structures. Micron mesh p(HEMA) hydrogel membranes were synthesized by using the UV-photopolymerization method, then modified with Reactive Red 241 (RR241) dye ligand to increase the affinity towards IgG. Characterizations of synthesized micron mesh p(HEMA)-RR241 hydrogel membranes were also performed. It was demonstrated by the characterization studies that; the dye was successfully incorporated into the membrane structure with the amount of 119.38 mg/g. The hydrophilic property of the hydrogel membrane was demonstrated by swelling tests and the swelling value of dye modified membrane was found to be 8 times higher than that of the plain membrane. Micron network structure, as well as the porosity, were demonstrated with SEM/ESEM studies. Optimization of IgG adsorption conditions was also studied at different parameters (pH, temperature, ion strength, initial IgG concentration). Optimum pH, temperature, and ionic strength were found to be 6.5, 25 °C, 0.05 M, respectively, and the maximum IgG absorption value was 10.27 mg/g. Finally, it was shown that the proposed materials can be used repeatedly by 5 adsorption-desorption cycles.

Magnetic poly(2-hydroxyethyl methacrylate) microspheres for affinity purification of monospecific anti-p46 kDa/Myo1C antibodies for early diagnosis of multiple sclerosis patients

The aim of the present study is to develop new magnetic polymer microspheres with functional groups available for easy protein and antibody binding. Monodisperse macroporous poly(2-hydroxyethyl methacrylate) (PHEMA-COOH) microspheres ~4 µm in diameter and containing ∼1 mmol COOH/g were synthesized by multistep swelling polymerization of 2-hydroxyethyl methacrylate (HEMA), ethylene dimethacrylate (EDMA), and 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA), which was followed by MCMEMA hydrolysis. The microspheres were rendered magnetic by precipitation of iron oxide inside the pores, which made them easily separable in a magnetic field. Properties of the resulting magnetic poly(2-hydroxyethyl methacrylate) (mgt.PHEMA) particles with COOH functionality were examined by scanning and transmission electron microscopy (SEM and TEM), static volumetric adsorption of helium and nitrogen, mercury porosimetry, Fourier transform infrared (FTIR) and atomic absorption spectroscopy (AAS), and elemental analysis. Mgt.PHEMA microspheres were coupled with p46/Myo1C protein purified from blood serum of multiple sclerosis (MS) patients, which enabled easy isolation of monospecific anti-p46/Myo1C immunoglobulin G (IgG) antibodies from crude antibody preparations of mouse blood serum. High efficiency of this approach was confirmed by SDS/PAGE, Western blot, and dot blot analyses. The newly developed mgt.PHEMA microspheres conjugated with a potential disease biomarker, p46/Myo1C protein, are thus a promising tool for affinity purification of antibodies, which can improve diagnosis and treatment of MS patients.

Affinity-recognition-based polymeric cryogels for protein depletion studies

Supermacroporous cryogels can be used for the depletion of highly abundant proteins prior to proteome investigations.

High capacity binding of antibodies by poly(hydroxyethyl methacrylate) nanoparticles

Poly(hydroxyethyl methacrylate) (PHEMA) nanoparticles with an average size of 150 nm in diameter and with a poly-dispersity index of 1.171 were produced by a surfactant free emulsion polymerization. Specific surface area of the PHEMA nanoparticles was found to be 1779 m(2)/g. Reactive imidazole containing 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) was used as a pseudo-specific ligand. IMEO was attached covalently onto the nanoparticles. PHEMA-IMEO nanoparticles were used for the affinity binding of immunoglobulin-G (IgG) from human plasma. To evaluate the degree of IMEO loading, the PHEMA nanoparticles were subjected to Si analysis by using flame atomizer atomic absorption spectrometer and it was estimated as 64.5 mg/g of polymer. The nanoparticles were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). IgG binding onto the PHEMA nanoparticles was found to be 5.2 mg/g. Much higher binding values (up to 843 mg/g) were obtained for the PHEMA-IMEO nanoparticles. IgG could be repeatedly bound and eluted on PHEMA-IMEO nanoparticles without noticeable loss in the IgG binding capacity.