Synthesis and characterization of biomimetic nanogels for immunorecognition.

Biomimetic nanoparticles are promising materials for biomedical and biotechnological applications. Cationic poly(N-isopropylacrylamide) (PNIPAM) nanogels containing charged amine groups brought by addition of 2-aminoethylmethacrylate hydrochloride (AEMH) or N-(3-aminopropyl) methacrylamide hydrochloride (APMH) as co-monomers were prepared by surfactant-free precipitation polymerization. The influence of the relative amount and mode of addition of the co-monomer on both the size and the amine group density of the nanogel particles was studied. Two nanogels, one prepared using APMH (1%mol/mol NIPAM, in batch) and another with AEMH (2%mol/mol NIPAM, by shot addition) as co-monomers, were selected for the covalent coupling of a Protein L-mimic ligand to free amine groups on the particles. The ability of the synthesized biomimetic nanoparticles for recognizing and binding human IgG (hIgG) molecules was assessed and the selectivity toward immunoglobulin molecules evaluated.

Affinity-based methodologies and ligands for antibody purification: advances and perspectives.

Many successful, recent therapies for life-threatening diseases such as cancer and rheumatoid arthritis are based on the recognition between native or genetically engineered antibodies and cell-surface receptors. Although naturally produced by the immune system, the need for antibodies with unique specificities and designed for single application, has encouraged the search for novel antibody purification strategies. The availability of these products to the end-consumer is strictly related to manufacture costs, particularly those attributed to downstream processing. Over the last decades, academia and industry have developed different types of interactions and separation techniques for antibody purification, affinity-based strategies being the most common and efficient methodologies. The affinity ligands utilized range from biological to synthetic designed molecules with enhanced resistance and stability. Despite the successes achieved, the purification "paradigm" still moves interests and efforts in the continuous demand for improved separation performances. This review will focus on recent advances and perspectives in antibody purification by affinity interactions using different techniques, with particular emphasis on affinity chromatography.

Adsorption of human IgG on to poly(N-isopropylacrylamide)-based polymer particles.

Thermosensitive poly(N-isopropylacrylamide)-based polymer particles were synthesised, and screened for the adsorption of human immunoglobulin G (hIgG). At pH 9 the adsorption on microgel particles was strongly affected by temperature, approximately 40 mg hIgG/g support (90% of initial hIgG) being adsorbed at 40 degrees C but only 10% of initial hIgG at 25 degrees C. At pH 5 the maximum adsorbed amount (20 mg hIgG/g support) was similar for both temperatures. The adsorption of hIgG on to charged poly(methyl methacrylate)/poly(N-isopropylacrylamide) core-shell latexes was negligible (5-10 mg hIgG/g support) at the same temperature and pH conditions. The lower adsorption of hIgG onto the core-shell particles is explained by steric interactions due to the small size of the shell.