Uniform Magnetic Core/Shell Microspheres Functionalized with Ni²⁺–Iminodiacetic Acid for One Step Purification and Immobilization of His-Tagged Enzymes

Abstract

A facile approach has been developed to synthesize Fe3O4/PMG (poly (N,N'-methylenebisacrylamide-co-glycidyl methacrylate)) core/shell microspheres using distillation-precipitation polymerization. Treating PMG shell with iminodiacetic acid (IDA) and Ni2+ yields composite microspheres of Fe3O4/PMG/IDA-Ni2+. The Ni2+ ions loaded on the surface of microspheres provide abundant docking sites for immobilization of histidine-tagged proteins. The high saturation magnetization of Fe3O4/PMG (23 emu/g), determined by vibrating sample magnetometer (VSM), allows an easy separation of the microspheres from solution under an external magnetic field. The composite microspheres were used to purify two His-tagged cellulolytic enzymes (Cel48F and Cel9G) directly from crude cell lysates with high binding affinity, capacity, and specificity. The microspheres can be recycled for many times without significant loss of binding capacity to enzymes. The immobilized enzymes on the surface of microspheres well retain their biological activities in degradation of cellulose. These materials show great potential in the biomedical and biotechnological applications that require low-cost purification of recombinant proteins and instant enzyme immobilization at an industrial scale.

Synthesis of hierarchical nickel anchored on Fe3O4@SiO2 and its successful utilization to remove the abundant proteins (BHb) in bovine blood

“…It is found that the outer shell of the particle exhibits a 20 fine increment in brightness compared with the dark inner core, which confirms the well-known core-shell structure of Fe 3 O 4 @SiO 2 particles, where Fe 3 O 4 is the magnetic core embedded within the silica matrix. It is noted that the SiO 2 shell structured Fe 3 O 4 @SiO 2 particles are rather well-dispersed, 25 determined by TEM are 20, 50 and 75 nm, the silica shell thickness of the nanoparticles increase with increasing the aqueous ammonia from 1 mL to 3 mL. This observation clearly demonstrates that the nanoparticle characteristics of Fe 3 O 4 @SiO 2 nanoparticles can be easily controlled by simply 30 varying the initial amount of NH 3 , it is also easily controlled by the TEOS, the reaction time.…”

“…[1][2][3][4][5][6][7] They have also found a wide range of applications in the enrichment of proteins and peptides in proteomics research. [8][9] To apply magnetic nanoparticles in proteomics applications, much work has been done to functionalize magnetic nanoparticles surface 25 with another phase to enhance the compatibility and functionality. Such functionalized magnetic nanoparticles can be a versatile platform for effective manipulation of various kinds of proteins, which is important in the field of proteomics.…”

“…In this study, we present a simple pathway to synthesize magnetic silica microspheres with coated nickel shell 20 for fast and efficient removal of abundant protein(BHb) in bovine blood. First, magnetite silica microspheres were synthesized and modified with NH 2 groups, Fe 3 O 4 @SiO 2 @NH 2 was coated with Ni metal via reduced by NaBH 4 in aqueous solution, leading to Ni-immobilized magnetite silica 25 microspheres (donated as Ni-MNs). Since the Ni-MNs possess high specific area and strong magnetism, they can be readily separated from their dispersion or mixture solution containing analytes with the assistance of an external applied magnetic field, thus achieving efficient removal of the targeted species.…”

Targeted delivery and pH-responsive release of stereoisomeric anti-cancer drugs using β-cyclodextrin assemblied Fe3O4 nanoparticles

“…The preparation of APTES-Fe 3 dispersed in ethanol and water, and 120 μL APTES was added into the solution under N 2 protection. After mechanically rabbling for 7 h, the suspended materials were separated and washed for three times, and the APTES-Fe 3 O 4 was obtained after vacuum drying for 24 h at 50 ℃.…”

“…Among the diverse integrated nanoparticles, magnetic Fe 3 O 4 nanoparticles (MNPs) with M a n u s c r i p t 2 excellent electrical and optical properties have attracted widespread interests due to their potential applications in the biomedical fields, including magnetic resonance imaging (MRI), [1] bioseparation, [2] immobilization of enzymes [3] and drug delivery. [4] As a kind of magnetic "smart" system, MNPs have been proved to be a promising candidate for tumor targeting because of unique magnetic responsiveness, low cytotoxicity as well as excellent biocompatibility.…”