Salt-Induced Disintegration of Lysozyme-Containing Polyelectrolyte Complex Micelles

S. Lindhoud, M.A. Cohen Stuart, W. Norde, R.J. de Vries, R. Schweins, L. Voorhaar

Research output: Contribution to journalArticleAcademicpeer-review

42 Citations (Scopus)

Abstract

The salt-induced disintegration of lysozyme-filled polyelectrolyte complex micelles, consisting of positively charged homopolymers (PDMAEMA150), negatively charged diblock copolymers (PAA42-PAAm417), and lysozyme, has been studied with dynamic light scattering (DLS) and small-angle neutron scattering (SANS). These measurements show that, from 0 to 0.2 M NaCl, both the hydrodynamic radius (Rh) and the core radius (Rcore) decrease with increasing salt concentration. This suggests that the micellar structures rearrange. Moreover, from 0.2 to 0.4 M NaCl the light-scattering intensity is constant. In this salt interval, the hydrodynamic radius increases, has a maximum at 0.3 M NaCl, and subsequently decreases. This behavior is observed in both a lysozyme-containing system and a system without lysozyme. The SANS measurements on the lysozyme-filled micelles do not show increased intensity or a larger core radius at 0.3 M NaCl. This indicates that from 0.2 to 0.4 M NaCl another structure is formed, consisting of just the diblock copolymer and the homopolymer, because at 0.12 M NaCl the lysozyme-PAA42-PAAm417 complex has disintegrated. One may expect that the driving force for the formation of the complex in this salt range is other than electrostatic
Original languageEnglish
Pages (from-to)11425-11430
JournalLangmuir
Volume25
Issue number19
DOIs
Publication statusPublished - 2009

Keywords

  • entrapping enzyme molecules
  • coacervate core micelles
  • electrostatic complexes
  • neutron-scattering
  • protein complexes
  • block-copolymers
  • acrylamide
  • stability
  • nanoparticles
  • mechanism

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