On the role of alginate structure in complexing with lysozyme and application for enzyme delivery

Fuenzalida J., Nareddy P., Moreno-Villoslada I., Moerschbacher B., Swamy M., Pan S., Ostermeier M., Goycoolea F.

Abstract

This study addresses the physicochemical properties and potential application of colloidal stable particles prepared by electrostatic self-assembly of alginate (Alg) and lysozyme (Lyz), here referred to as Alg-Lyz nanocomplexes (Alg-Lyz NCXs). The M/G ratio, molecular weight (Mw) or the addition of Ca2+, all influence the capacity of Alg to associate Lyz as well as the size and zeta potential of Alg-Lyz NCXs. Systems comprising low-Mw Alg (Alg A Mw ~4000gmol-1 and M/G ~1.42 or Alg B Mw ~7000gmol-1 and M/G ~5.00) allow to glean further understanding of the influence of Alg block composition on the thermodynamic properties and on the underlying interactions between Alg and Lyz by ITC. Alg B is thought to exhibit a more extended structure leading to higher cross-linking with Lyz. Alg-Lyz NCXs, though retain the activity of Lyz, it is lower than that of the free enzyme. However, they are effective to co-associate a second enzyme, β-lactamase (BLA), and its activity is sensitive to the ionic strength.