PORPHYRIN NANOPARTICLES WITH HIGH MAGNETITE CONTENT AS A SELECTIVE SORBENT FOR ANGIOTENSIN

SILVIA SOTO ESPINOZA; NORA VIZIOLI; ROMINA CARBALLO; PAULA DABAS

Mendoza

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

LACE

Several kinds of magnetic nanoparticles (MNP) havebeen produced from both natural and synthetic polymers with the intention toincorporate groups on the surface or to treat their surface to perform, for instance,selective separations1. For example, the presence of a metal ion inthe porphyrin core provides selectivity to nanoparticles when it is coveredwith such compounds. In the present work, the interaction of MNP with a modelpeptide, such as angiotensin I, was thoroughly evaluated. The MNP weresynthesized by co-precipitation of iron salts in alkaline medium and inertatmosphere2. Particles were subsequently coated with Cu(II)-porphyrinin organic medium3. Bare and modified MNP (CuPP@MNP) werecharacterized by means of vibrating sample magnetometery, microscopy, zetapotential, UV-visible and Fourier transform infrared spectroscopy. To assessthe interaction of MNP with angiotensin I, an exactly measured amount of MNPwas kept in contact with peptide solutions. The adsorption assays wereperformed at pH that ranged from 2.5 to 10.0. MPN were separated from solutionwith an external magnet and re-dispersed after magnet removal. Aliquots ofsupernatant were taken at different times and analyzed by CE in a P/ACE MDQsystem, using a 50 mM sodium phosphate solution, pH 7.0, as backgroundelectrolyte. Different desorption conditions were tested including pH of theelution buffer, acetonitrile percentage, sodium chloride content, andconcentration of imidazole. Quantification of angiotensin I demonstrated thatdifferential selectivity and a high peptide adsorption rate (over 80%) was obtainedat pH 7.0. Angiotensin I adsorption onto bare MNP at pH 5.0 could be explainedby presence of an aspartic acid residue on its amino acid sequence which confersaffinity to the iron present in the MNP. The interaction between angiotensin Iand CuPP@MNP fitted a Langmuir-Freundlich model during the first 30 min periodof contact (Kd: 3.31e-7 mg/mL, qm: 0.92 mg/mL, n: 2.86). After that,the adsorption isotherm followed the Freundlich model (Kf: 3.29 mg/mL, n: 5.34),indicating that interactions of different intensity would be present.References:1. Ka?ička V. Electrophoresis2018, 39, 209-234.2. Ramirez LP, Landfester K. Macromol. Chem. Phys. 2003,204, 22?31.3. 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.