Interaction between lysozyme and colloidal poly(NIPAM-co-AAc) microgels
2010 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 347, no 2, 241-251 p.Article in journal (Refereed) Published
The interaction between lysozyme and colloidal poly(NIPAM-co-acrylic acid) microgels is investigated in aqueous solutions at neutral pH. Lysozyme binding isotherms, obtained within the ionic strength range 10-220 mM, indicate that the maximum uptake at 10 mM is 2.4 g lysozyme per gram dry gel, and that the uptake capacity decreases with increasing ionic strength to approximately 0 at 220 mM. Swelling isotherms, obtained from photon correlation spectroscopy measurements, show that the binding is accompanied by a substantial deswelling of the microgels. The microgel suspension is stable up to a protein-to-polymer charge ratio in the microgels of about 0.6, largely independent of ionic strength, whereas flocculation/sedimentation occurs at higher charge ratios. The charge ratio 0.6 corresponds to a zeta-potential of about -6 mV, as obtained from measurements of electrophoretic mobility. Binding and swelling isotherms are analyzed in detail and compared with predictions of theoretical model calculations. The influence of protein-protein attraction is highlighted, as well as the interplay between electrostatic interactions and network elasticity.
Place, publisher, year, edition, pages
2010. Vol. 347, no 2, 241-251 p.
microgel, NIPAM, acrylic acid, lysozyme, protein, colloidal stability, electrophoretic mobility
Research subject Physical Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-101244DOI: 10.1016/j.jcis.2010.03.072ISI: 000278707400012PubMedID: 20417522OAI: oai:DiVA.org:uu-101244DiVA: diva2:212201