title: Electrolyte effect on the phase behavior of silica nanoparticles with lysozyme and bovine-serum-albumin proteins.
abstract: Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) studies have been carried out to investigate the effect of an electrolyte on the phase behavior of anionic silica nanoparticles with two globular proteins-cationic lysozyme [molecular weight (MW) 14.7 kDa] and anionic bovine serum albumin (MW 66.4 kDa). The results are compared with our earlier published work on similar systems without any electrolyte [I. Yadav, S. Kumar, V. K. Aswal, and J. Kohlbrecher, Phys. Rev. E 89, 032304 (2014)]. Both the nanoparticle-protein systems transform to two phase at lower concentration of protein in the presence of an electrolyte. The autocorrelation function in DLS suggests that the diffusion coefficient (D) of a nanoparticle-protein system decreases in approaching two phase with the increase in protein concentration. This variation in D can be attributed to increase in attractive interaction and/or overall increase in the size. Further, these two contributions (interaction and structure) are determined from the SANS data. The changes in the phase behavior of nanoparticle-protein systems in the presence of an electrolyte are explained in terms of modifications in both the repulsive and attractive components of interaction between nanoparticles. In a two-phase system individual silica nanoparticles coexist along with their fractal aggregates.
authors.affiliation: Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: Indresh
authors.initials: I
authors.lastname: Yadav
authors.affiliation: Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: V K
authors.initials: VK
authors.lastname: Aswal
authors.affiliation: Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 PSI Villigen, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Kohlbrecher
mesh_terms: D000818:Animals; D002417:Cattle; D004058:Diffusion; D009113:Muramidase / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*
chemical_list: D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D012822:Silicon Dioxide; D009113:Muramidase