Immobilization of BSA on Silica-Coated Magnetic Iron Oxide Nanoparticle

Abstract

Colloid stable magnetic iron oxide nanoparticles, which undergo reversible precipitation from aqueous solution with external magnetic flux, can have many potential applications. However, the lack of generic homogeneous anchoring sites on a magnetic nanoparticle surface for binding of chemical/biochemical species under a wide range of conditions is one key problem. It is shown that a small size iron oxide nanoparticle encapsulated in a thin silica shell can offer specific sites to bind protein molecules via surface silanol groups electrostatically at pH 7.4 without severe denaturing of the bulky protein structure. As a result, we show that a high loading of bovine serum albumin (BSA) of 85 mg/g can be anchored on the silica-encapsulated iron oxide. FTIR, circular dichroism, and binding constant (using site I and site II drugs) measurements show only a small degree of conformational alteration upon immobilization. A partial unfolding of secondary structures on the external sheath of the protein due to competitive hydrogen bonding interactions of functional groups such as -CdO and -NH with surface acidic hydroxyl groups is shown to take place despite the use of buffered pH 7.4 solution. In contrast to the blockage of drug binding sites reported in the case of anchored BSA on extended silica surface, our results clearly show that the internal hydrophobic sites I and II of the immobilized BSA on this silica-based magnetic nanoparticle remain intact for drugs binding at a high degree.

Functionalized magnetic iron oxide/alginate core-shell nanoparticles for targeting hyperthermia

“…Superparamagnetic iron oxide nanoparticles (SPIONs), including magnetite (Fe 3 O 4 ) and maghemite (γ-Fe 2 O 3 ), have been extensively utilized in biomedical applications, including as magnetic resonance imaging contrast agents, 1 for biocatalysis, 2 for biological separation, 3 for biosensing, 4 diagnostic medical devices, 5 and hyperthermia. Among these applications, hyperthermia 6 is a physical therapy in which SPIONs generate heat and thus kill cancer cells when they are exposed to an external magnetic field.…”

Zincon as resonance Raman probe for quantitative evaluation of proteins

“…[24,25] The intensities of the RR band at 1338 cm −1 with different dilutions of FBS are shown in Fig. 6.…”

Adsorption of Protein on a Au Surface Studied by All-Atom Atomistic Simulations

“…Due to their high affinities for hydrophobic surfaces, adsorbed proteins can have a less native structure than when adsorbed on hydrophilic surfaces, leading to severe protein denaturation 67 . In addition, NP surfaces may take up proteins depending on their isoelectric points in a rather narrow pH range 68 . It has also been observed that an increase in electrostatic interaction is generally accompanied by a reduction of the modification of the native structure 69 .…”