A Combined Experimental and Molecular Simulation Study of Insulin-chitosan Complexation Driven by Electrostatic Interactions

CECILIA PRUDKIN SILVA; OSCAR E PÉREZ; KARINA D MARTÍNEZ; FERNANDO LUIS BARROSO

JOURNAL OF CHEMICAL INFORMATION AND MODELING

AMER CHEMICAL SOC

Lugar: Washington; Año: 2020

1549-9596

Protein-polysaccharide complexes constructed via self-assembly method are often used to develop novel biomaterials for a wide range of applications in biomedicine, food and biotechnology. The objective of this work was to investigate theoretically and to demonstrate via constant-pH Monte Carlo simulations that the complexation phenomenon between insulin (INS) and the cationic polyelectrolyte chitosan (CS) is mainly driven by an electrostatic mechanism. Experimental results obtained from FTIR spectra and ζ ? potential determinations allowed us to complement the conclusions. The characteristic absorption bands for the complexes could be assigned to a combination of signals from CS amide I and INS amide II. The second peak corresponds to the interaction between the polymer and the protein at the level of amide II. INS-CS complexation processes not expected when INS is in its monomeric form, but for both tetrameric and hexameric forms, incipient complexation due to charge regulation mechanism took place at pH 5. The complexation range was observed to be 5.5