Depletion of albumin and immunoglobulin G from human serum using epitope‐imprinted polymers as artificial antibodies

Abstract

Serum is a readily available source for noninvasive studies in clinical research, but it contains abundant proteins such as albumin and immunoglobulin G that can hinder the presence of low-abundant proteins as well as decrease sample loading capacity of analytical methods. Therefore, depletion of these two proteins is required to observe low-abundance serum proteins. Molecularly imprinted polymers are template-induced artificial antibodies with the ability to recognize and selectively bind the target molecule. In this study, artificial albumin and immunoglobulin G antibodies were developed by using two epitopes of human serum albumin and immunoglobulin G as templates. Acrylic acid, acrylamide, and N-acryl tyramine were the corresponding monomers; N,N'-ethylene bisacrylamide served as a cross-linker, and cellulosic fibers were used as a supporting matrix. The adsorption capacity of these artificial antibodies was 15.2 mg, 10 mg, and 15 μL per gram for human serum albumin, immunoglobulin G, and human serum, respectively. The dissociation constant (Kd ) of these artificial antibodies toward the human serum albumin and immunoglobulin G was 1 μM and 0.6 μM, respectively. The biomimetic properties of these artificial antibodies, coupled with their economical and rapid production, high specificity and their reusability, make them attractive for protein separation and analysis.

Rapid Complexation of Aptamers by Their Specific Antidotes

“…Already after 2 min, aptamer/AD complexes were generated. Thereby, the ability of the AD to quickly bind to complementary sequences was demonstrated in human serum containing thousands of proteins with varying concentrations, wherein albumin and immunoglobulin G (IgG) account for more than 60% [ 13 ]. Furthermore, the anticoagulant effect of NU172 could be abrogated 5 min after the addition of 1 μM NU172 (AD) to 1 μM NU172 in human whole blood.…”

Identification of N-Glycosylation in Hepatocellular Carcinoma Patients’ Serum with a Comparative Proteomic Approach

“…Therefore, serum proteins can reflect the general situation of the human organism. However, high abundant proteins such as albumin and IgG constitute approximately 60–80% of the total serum proteins[16,17], making the detection of medium- and low abundant proteins extremely challenging. In our study, we applied the Proteo-Miner™ Protein Enrichment Kits and hydrophilic affinity (HA) method for enrichment of proteins.…”

Liquid phase based separation systems for depletion, prefractionation, and enrichment of proteins in biological fluids and matrices for in‐depth proteomics analysis—An update covering the period 2011–2014

“…The depletion methods in proteomics are used primarily to reduce the complexity of proteomic samples by depleting HAPs (i.e., albumin, immunoglobulin G (IgG), immunoglobulin A (IgA), immunoglobulin M (IgM), transferrin, haptoglobin and α-2-macroglobulin) and at the same time to narrow the differences of protein concentrations in a given proteomic sample [3-10]. The reduction of complexity can be performed by classical methods such as organic solvent solubilization and precipitation methods and by immuno depletion methods [3, 4].…”

“…In this study, artificial albumin and IgG antibodies were developed by using two epitopes of human serum albumin and IgG as templates [10]. Acrylic acid, acrylamide, and N -acryl tyramine were used as monomers, N,N′ -ehtylene bisacrylamide served as a crosslinker and cellulosic fibers were the supporting matrix.…”