title: β-Lactoglobulin (BLG) binding to highly charged cationic polymer-grafted magnetic nanoparticles: effect of ionic strength.
abstract: Poly(2-(methacryloyloxy)ethyltrimethyl ammonium chloride) (PMATAC) modified magnetic nanoparticles (NPs) with a high zeta potential of ca. 50mV were synthesized by atom transfer radical polymerization (ATRP). The prepared NPs consist of a magnetic core around 13nm and a PMATAC shell around 20nm attached on the surface of magnetic nanoparticles. Thermodynamic binding parameters between β-lactoglobulin and these polycationic NPs were investigated at different ionic strengths by high-resolution turbidimetry, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). Both turbidity and ITC show that binding affinities for BLG display a non-monotonic ionic strength dependence trend and a maximum appears at ionic strength of 50mM. Such observation should arise from the coeffects of protein charge anisotropy visualized by DelPhi electrostatic modeling and the strong electrostatic repulsion among highly charged NPs at a variety of ionic strengths.
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Li
authors: L
authors: Qin
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China. Electronic address: yshxu@ecust.edu.cn.
authors: Yisheng
authors: Y
authors: Xu
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Haoya
authors: H
authors: Han
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Miaomiao
authors: M
authors: Liu
authors: College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China.
authors: Kaimin
authors: K
authors: Chen
authors: Testing Center, Shanghai Research Institute of Chemical Industry, Shanghai 200062, China.
authors: Siyi
authors: S
authors: Wang
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Jie
authors: J
authors: Wang
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Jun
authors: J
authors: Xu
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors: Li
authors: L
authors: Li
authors: State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China. Electronic address: guoxuhong@ecust.edu.cn.
authors: Xuhong
authors: X
authors: Guo
mesh_terms: D000818:Animals; D016880:Anisotropy; D002151:Calorimetry; D002412:Cations / Q000737:chemistry*; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D007782:Lactoglobulins / Q000737:chemistry*; D008027:Light; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods; D009391:Nephelometry and Turbidimetry; D009994:Osmolar Concentration; D011108:Polymers / Q000737:chemistry*; D011485:Protein Binding; D012542:Scattering, Radiation; D055672:Static Electricity; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D002412:Cations; D007477:Ions; D007782:Lactoglobulins; D058185:Magnetite Nanoparticles; D011108:Polymers
keywords: Cationic polymer shell; Ionic strength; Magnetic nanoparticles; Protein binding; β-Lactoglobulin