Publications by authors named "Sonia Maria Alves Bueno"

The ortho-phospho-tyrosine (P-Tyr) pseudoaffinity ligand was immobilized via ether linkage onto polyacrylamide-alginate (PAAm-Alg)-epoxy cryogels prepared according to two different approaches in order to explore their performance in the immunoglobulin G (IgG) purification from human serum. In the first approach, the P-Tyr was attached to cryogel prepared by cryocopolymerization of acrylamide and alginate with allyl glycidyl ether (AGE) as functional comonomer, and methylenebisacrylamide and Ca(II) as crosslinkers, obtaining the PAAm-Alg-AGE-P-Tyr. In the second approach, the PAAm-Alg was synthesized under the same conditions, but without AGE, and the P-Tyr was coupled to epichlorohydrin (ECH)-activated cryogel, obtaining the PAAm-Alg-ECH-P-Tyr.

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Iminodiacetic acid (IDA) is one of the chelating ligands most frequently employed in immobilized metal-ion affinity chromatography (IMAC) due to its ability to act as electron-pair donor, forming stable complexes with intermediate and borderline Lewis metal ions (electron acceptor). Thus, IDA can also be employed in ion exchange chromatography to purify positively charged proteins at neutral pH values. This study aimed to evaluate IDA as an ionogenic group (ion exchanger) immobilized on poly (ethylene vinyl alcohol) (PEVA) hollow fiber membranes for immunoglobulin G (IgG) monoclonal antibody (MAb) purification.

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In recent decades cryogels as monolithic materials have gained interest as stationary phase in chromatography for purification of biomolecules. In this study, polyacrylamide-alginate (PAAm-Alg) monolithic cryogels were prepared by cryo-copolymerization of acrylamide and alginate monomers and methylene-bisacrylamide as crosslinker to be used as a matrix in affinity chromatography for purification of proteins. Ortho-phospho-L-tyrosine (P-Tyr) was covalently attached onto PAAm-Alg cryogels via bisoxirane-activation (PAAm-Alg-Bix-P-Tyr) and both derivatized and non-derivatized cryogels were utilized for the purification of immunoglobulin G (IgG) from human serum.

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The behavior of human immunoglobulin G (IgG) and antigen-binding fragment (Fab fragment) adsorption onto phospho-l-tyrosine immobilized on agarose (P-Tyr-agarose) was evaluated by pseudoaffinity chromatography. The effects of buffer systems MES, MOPS, Bis-Tris, Tris-HCl and sodium phosphate (NaP) and pH on IgG adsorption were studied and high purity values were obtained (96%, based on ELISA analysis of albumin, transferrin and immunoglobulins A, G and M) when IgG was purified from human plasma diluted in 10 mmol L NaP buffer at pH 6.0.

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The present study evaluated the phosphorylated-tyrosine (P-Tyr) based pseudobioaffinity adsorbent for the purification of human immunoglobulin G (IgG). P-Tyr was selected as a ligand to mimic the natural interactions that occur between the immunoreceptor tyrosine-based activation motif and the IgG. The ligand was coupled to bisoxirane-activated agarose gel and the effect of buffer system, pH, and conductivity was performed to elucidate the nature of IgG-P-Tyr interactions.

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This study evaluated the feasibility of using immobilized metal-ion affinity chromatography (IMAC) for separation of human Fab fragments using four different transition metal ions copper, nickel, zinc, and cobalt chelated to CM-Asp (carboxymethylaspartate) immobilized on the agarose gel. The Fab and Fc fragments (from human IgG digested with papain) interacted differently with the chelates studied, depending on the adsorption buffer system. The interaction between chelate and Fc fragment is predominantly based on the coordination bonds using adsorption buffer containing NaCl.

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Iminodiacetic acid (IDA) and tris(2-aminoethyl)amine (TREN) chelating ligands were immobilized on poly(ethylene vinyl alcohol) (PEVA) hollow-fiber membranes after activation with epichlorohydrin or butanediol diglycidyl ether (bisoxirane). The affinity membranes complexed with Cu(II) were evaluated for adsorption of human immunoglobulin G (IgG). The effects of matrix activation and buffer system on adsorption of IgG were studied.

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The number of studies on gene therapy using plasmid vectors (pDNA) has increased in recent years. As a result, the demand for preparations of pDNA in compliance with recommendations of regulatory agencies (EMEA, FDA) has also increased. Plasmid DNA is often obtained through fermentation of transformed Escherichia coli and purification by a series of unit operations, including chromatography.

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The amino acid ortho-phosphoserine (OPS) immobilized on agarose gel was evaluated as a ligand for adsorption of polyclonal human immunoglobulin G (IgG) from human serum in the presence of low ionic strength buffers. Screening of buffer systems showed sodium phosphate as the buffer that exhibited higher IgG purity values. Through breakthrough curve analysis for agarose-OPS (feeding of 31.

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The adsorbent omega-aminodecyl-agarose was evaluated as to its feasibility for the adsorption of human serum and plasma proteins, aiming at the purification of immunoglobulin G (IgG). The contribution of electrostatic and hydrophobic interactions (mixed-mode) and the effects of buffer system on the adsorption of serum proteins were also studied. The adsorption isotherm parameters of human serum albumin (HSA) and IgG were evaluated, pointing to the existence of cooperative effects in the process.

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The omega-aminohexyl diamine immobilized as ligand on CNBr- and bisoxirane-activated agarose gel was evaluated for the purification of human immunoglobulin G (IgG) from serum and plasma by negative affinity chromatography. The effects of matrix activation, buffer system, and feedstream on recovery and purity of IgG were studied. A one-step purification process using Hepes buffer at pH 6.

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Tris(2-aminoethyl)amine (TREN) - a chelating agent used in IMAC - immobilized onto agarose gel was evaluated for the purification of IgG from human serum by negative chromatography. A one-step purification process allowed the recovery of 73.3% of the loaded IgG in the nonretained fractions with purity of 90-95% (based on total protein concentration and nephelometric analysis of albumin, transferrin, and immunoglobulins A, G, and M).

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The purification of IgG from human plasma was studied by comparing two affinity membranes complexed with Ni(II), prepared by coupling iminodiacetic acid (IDA) and Tris(2-aminoethyl)amine (TREN) to poly(ethylenevinyl alcohol), PEVA, hollow fiber membranes. The Ni(II)-TREN-PEVA hollow fiber membrane had lower capacity for human IgG than the complex Ni(II)-IDA-PEVA, but with similar selectivity. The IgG in peak fractions eluted from the Ni(II)-IDA-PEVA with a stepwise concentration gradient of Tris-HCl pH 7.

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Inabilities to process particulate material and to allow the use of high flow rates are limitations of conventional chromatography. Membranes have been suggested as matrix for affinity separation due to advantages such as allowing high flow rates and low-pressure drops. This work evaluated the feasibility of using an iminodiacetic acid linked poly(ethylenevinyl alcohol) membrane in the immobilized metal ion affinity chromatography (IMAC) purification of a human proinsulin(His)(6) of an industrial insulin production process.

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This work investigated the adsorption of autoantibodies such as anti-SS-A/Ro, anti-SS-B/La, anti-Sm, and anti-dsDNA on protein L-agarose gel. In order to determine better conditions for IgG adsorption on this matrix, some buffer systems were tested. Adsorption data were analyzed using the Langmuir and Langmuir-Freundlich isotherm models.

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The large scale production of monoclonal antibodies (McAbs) has gaining increased relevance with the development of the hybridoma cell culture in bioreactors creating a need for specific efficient bioseparation techniques. Conventional fixed bead affinity adsorption commonly applied for McAbs purification has the drawback of low flow rates and colmatage. We developed and evaluated a immobilized metal affinity chromatographies (IMAC) affinity membrane for the purification of anti-TNP IgG(1) mouse McAbs.

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