STUDY ON THE INTERACTION BETWEEN MAGNETIC NANOPARTICLES AND PEPTIDES BY CAPILLLARY ELECTROPHORESIS

BERENICE D. CROS; DELFINA LAVARI; GABRIELA V. LEZCANO; ARACELI ARELLANO; SOTO ESPINOSA SL; CARBALLO R.; NORA M VIZIOLI

Mendoza, Argentina

Simposio; 24th Latin-american Symposium on biotechnology , biomedical, biopharmaceutical, and industrial applications of capilary electrophoresis Microchip technology; 2018

National University of Cuyo Mendoza, Argentina and University of Buenos Aires Buenos Aires, Argentina

In this work, the interaction of magnetic nanoparticles (MNP) with peptides was studied to evaluate MNP as a potential pseudo-stationary phase in capillary electrophoresis (CE) techniques. The MNP were synthesized by co-precipitation of iron salts in alkaline medium and inert atmosphere1. Particles were subsequently coated with the corresponding metal-porphyrin in organic medium2. Different systems were studied: bare MNP and MNP modified with metal-porphyrin Co(II) and Ni(II). Bare and modified MNP were characterized by means of vibrating sample magnetometery, microscopy, UV-Visible spectroscopy, and zeta potential. In order to assess the interaction of MNP with the synthetic bioactive peptides angiotensin I and oxytocin, an exactly measured amount of MNP was kept in contact with peptide solutions. The adsorption assays were performed at pH 5.0 and pH 7.0. Aliquots of supernatant were taken at different times and analyzed by CE in a P/ACE MDQ system, using a 50 mM sodium phosphate solution, pH 7.0, as background electrolyte. Quantification of peptides demonstrated that both the MNP modified with Co(II)-porphyrin and MNP modified with Ni(II)-porphyrin had a stronger interaction with angiotesin I than with oxytocin. The adsorption of angiotensin I to bare MNP could mainly attributed to electrostatic interaction and to the presence of an aspartic residue to link with Fe(III). Interaction of oxytocin with Co(II)-porphyrin MNP was a little more appreciable than with the Ni(II)-porphyrin MNP, which could be explained through the low-spin Co(II) ions in non planar Co(II)-porphyrin complexes activated by core contraction of porphyrin macrocycles. Such complexes can be further activated by axial ligation of imidazole providing greater affinity for angiotensin I.The MNP under study have demonstrated to be selective for the two assayed model peptides. Physicochemical characteristics and their behavior as peptide adsorbents were reproducible, which makes expect that their use as a pseudo-stationary phase will be potentially successful.