The usage of composite nanomaterials in biomedical engineering applications

Nanotechnology is still developing over the decades and it is commonly used in biomedical applications with the design of nanomaterials due to the several purposes. With the investigation of materials on the molecular level has increased the develop composite nanomaterials with exceptional properties using in different applications and industries. The application of these composite nanomaterials is widely used in the fields of textile, chemical, energy, defense industry, electronics, and biomedical engineering which is growing and developing on human health. Development of biosensors for the diagnosis of diseases, drug targeting and controlled release applications, medical implants and imaging techniques are the research topics of nanobiotechnology. In this review, overview of the development of nanotechnology and applications which is use of composite nanomaterials in biomedical engineering is provided.

O-carboxymethyl chitosan Schiff base complexes as affinity ligands for immobilized metal-ion affinity chromatography of lysozyme

We synthesized Ni²⁺-attached O-Carboxymethyl chitosan Schiff base complexes embedded composite cryogels (Ni²⁺-O-CMCS-CCs) by means of polymerization of gel-forming precursors at subzero temperatures. Prepared affinity cryogel showed excellent adsorption performance for lysozyme selected as model protein to test adsorption parameters, demonstrating an adsorption capacity of 244.6 mg/g (15.3 mg/g for Ni²⁺ minus O-CMCS-CCs), with fast adsorption equilibrium within 30 min and good reversibility. The performance of Ni²⁺-O-CMCS-CCs for lysozyme was also evaluated by SDS-PAGE, and a purification efficiency of 86.9% with 89.5% purification yield was determined. The swelling test, FT-IR, and SEM analysis were carried out for the characterization of Ni²⁺-O-CMCS-CCs. At the end of 35 adsorption-desorption cycles, there was no significant change in the adsorption capacity.

Methacryloylamidoglutamic acid having porous magnetic beads as a stationary phase in metal chelate affinity chromatography

We have prepared a novel magnetic metal-chelate adsorbent utilizing methacryloylamidoglutamic acid (MAGA) as a metal-chelating ligand. MAGA was synthesized by using methacryloyl chloride and L-glutamic acid dihydrochloride. Magnetic beads with an average diameter of 50-100 microm were produced by suspension polymerization of 2-hydroxyethyl methacrylate (HEMA) and MAGA in the presence of Fe3O4 particles carried out in an aqueous dispersion medium. Magnetic beads were charged with the Cu2+ ions directly via MAGA for the adsorption of cytochrome c (cyt c) from aqueous solutions. The maximum cyt c adsorption capacity of the Cu2+-chelated beads (0.86 mmol/g Cu2+ loading) was found to be 37 mg/g at pH 8.0 in phosphate buffer. Cyt c adsorption on the poly(HEMA-MAGA) beads was 15.4 mg/g. Cu2+ charging increased the cyt c adsorption significantly (37 mg/g). Cyt c adsorption decreased with increasing temperature. Cyt c molecules could be adsorbed and desorbed five times with these adsorbents without noticeable loss in their cyt c adsorption capacity. The resulting magnetic chelator beads posses excellent long term storage stability.

Magnetic IDA-modified hydrophilic methacrylate-based polymer microspheres for IMAC protein separation

Preparation of a new type of magnetic non-porous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) microspheres with hydrophilic properties containing coupled iminodiacetic acid (IDA) is described. The prepared microspheres were used for the immobilization of Ni(II) or Fe(III) ions to show their application in protein binding studies. Human IgG was bound to magnetic Ni(II)-IDA-modified microspheres and conditions of its adsorption and elution were optimized. Non-specific binding of the protein to magnetic microspheres in the absence of Ni(II) ions was low. Fe(III) ions immobilized on magnetic IDA-modified microspheres were used for the specific binding of porcine pepsin, as a model phosphoprotein. The ability of phosphate buffer to release the adsorbed enzyme from the microspheres and a low adsorption of the dephosphorylated protein indicate the participation of phosphate groups in the pepsin interaction. The elaborated method represents a rapid technique that can be used not only for the separation of proteins but also for analytical purposes.

Effect of the matrix structure and concentration of polymer-immobilized Ni2+–iminodiacetic acid complexes on retention of IgG1

Terpolymer bead particles (100-350 microm in diameter) were prepared by suspension radical polymerization from methacrylate esters [2,3-epoxypropyl methacrylate (GMA), 2-(2-hydroxyethoxy)ethyl methacrylate (DEGMA) and ethylene dimethacrylate (EDMA)] and subsequently derivatized affording iminodiacetic acid (IDA) chelating sorbents. The sorbents differed in pore volumes (0-0.7 cm3/g) and specific surface areas (0.03-9.8 m2/g) of their matrices as well as in the amounts of immobilized Ni2+-IDA complexes (0.03-1.58 mmol/g). The binding of imidazole was studied by frontal chromatography to evaluate the accessibility of Ni2+-IDA complexes. It was found that an increase in the bonded imidazole content with increasing immobilized Ni2+-IDA concentration was strongly dependent on the matrix morphology. A higher pore volume of the matrix significantly improved the utilizability of Ni2+-IDA complexes for imidazole binding. The performance of the sorbents based on two porous matrices with immobilized Ni2+-IDA concentration (0.1-1.58 mmol/g) differing in pore size distributions was compared in immobilized metal affinity chromatography (IMAC) of monoclonal mouse immunoglobulin IgG1 specific against human choriogonadotropic hormone (GTH-spec IgG1). The results have shown that sorbents based on matrix with large pores (up to 20 microm in diameter) exhibited high protein binding capacities. The GTH-spec IgG1 (Mw=158,000) was eluted from all the sorbents in its native form as was confirmed by MALDI-TOF.