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

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 ~4000 g mol-1 and M/G ~1.42 or Alg B Mw ~7000 g mol-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.