Lysozyme - Alginate nanocomplex: The role of alginate composition

Abstract

In the present work we investigated the electrostatic self-assembly of nanocomplexes (NCXs) made of lysozyme (Lyz) and different alginates (Alg A Mw ~4kD and M/G ~1.42 or Alg B Mw ~7kD and M/G~5.00) to establish a relationship between the alginate structure and both the physical (size and zeta potential, optical density) and the thermodynamic properties of the systems. It was found that the alginate rich in mannuronic unit (Alg B) had a greater binding stoichiometry and lower affinity than Alg A, a fact that correlated with a more extended structure that in turn affected the capacity to form hydrogen bonds associated with the differences in charge distribution. Both alginates show higher affinity and temperature stability than poly-acrylic acid (PAA), showing the importance of the polyasaccharide structure in the NCXs formation. For the first time we showed that the M/G ratio plays a role on the affinity of interaction of alginate and lysozyme. Finally, these NCXs seem promising systems for biomedical application due to their in vitro biocompatibility and macromolecules retention capacity.