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

GABRIELA LEZCANO; ROMINA CARBALLO; DELFINA LAVARI; SILVIA SOTO ESPINOZA; BERENICE D. CROS; ARACELI ARELLANO; NORA VIZIOLI

Mendoza

Simposio; 24th Latin- American Symposium on Biotechnology, Biomedical, Biopharmaceutical and Industrial Applications of Capillary Electrophoresis and Microchip Technolog; 2018

LACE

In this work, the interactionof magnetic nanoparticles (MNP) with peptides was studied to evaluate MNP as apotential pseudo-stationary phase in capillary electrophoresis (CE) techniques.The MNP were synthesized by co-precipitation of iron salts in alkaline mediumand inert atmosphere1. Particles were subsequently coated with thecorresponding metal-porphyrin in organic medium2. Different systems werestudied: bare MNP and MNP modified with metal-porphyrin Co(II) and Ni(II). Bareand modified MNP were characterized by means of vibrating sample magnetometery,microscopy, UV-Visible spectroscopy, and zeta potential. In order to assess theinteraction of MNP with the synthetic bioactive peptides angiotensin I andoxytocin, an exactly measured amount of MNP was kept in contact with peptidesolutions. The adsorption assays were performed at pH 5.0 and pH 7.0. Aliquotsof 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. Quantificationof peptides demonstrated that both the MNP modified with Co(II)-porphyrin and MNPmodified with Ni(II)-porphyrin had a stronger interaction with angiotesin Ithan with oxytocin. The adsorption of angiotensin I to bare MNP could mainly attributedto electrostatic interaction and to the presence of an aspartic residue to linkwith Fe(III). Interaction of oxytocin with Co(II)-porphyrin MNP was a littlemore appreciable than with the Ni(II)-porphyrin MNP, which could be explained throughthe low-spin Co(II) ions in non planar Co(II)-porphyrin complexes activated bycore contraction of porphyrin macrocycles. Such complexes can be furtheractivated by axial ligation of imidazole providing greater affinity for angiotensinI.The MNP under study havedemonstrated to be selective for the two assayed model peptides. Physicochemicalcharacteristics and their behavior as peptide adsorbents were reproducible,which makes expect that their use as a pseudo-stationary phase will be potentiallysuccessful. References:1. Ramirez LP, Landfester K. Macromol. Chem. Phys. 2003,204, 22?31.2. Hamer M,Carballo RR, Cid N, Rezzano IN. Electrochim. Acta 2012, 78, 302-305. Acknowledgements:Financialsupport for this work has been provided by ANPCYT, CONICET, and Universidad deBuenos Aires.