Preparation of magnetic immobilized metal affinity separation media and its use in the isolation of proteins

Automated and Rapid Easy-to-Use Magnetic Solid-Phase Extraction System for Five Heavy Metals in Cereals and Feeds

A rapid, accurate, and ecofriendly pretreatment plays an extremely important role prior to ICP-MS for heavy metal analysis. In order to improve the pretreatment efficiency, a high-throughput and automatic magnetic solid-phase extraction of five heavy metals (Cd, Pb, Mn, Cu, and Zn) was carried out by a magnet-controlled pretreatment system with an ecofriendly diluted acid as an extracting agent and carboxyl-functionalized magnetic beads as a pretreatment material. Key conditions, including the pH, adsorption time, and eluent solution, were optimized. The time for purification and enrichment was only 8 min. The adsorption capacities of the carboxyl-functionalized magnetic beads were in the range of 152~426 mg g^-1. The preconcentration factor of Cu was 40, and others were 200. In the optimal conditions, the limits of detection for Mn, Zn, Cd, Cu, and Pb by ICP-MS were 3.84, 2.71, 0.16, 11.54, and 6.01 ng L^-1, respectively. The percentage recoveries were in the range of 80~110%, and the relative standard deviations were less than 3%. The developed method was in good agreement with traditional standard microwave digestion. Additionally, the designed system could simultaneously process up to 24 samples within 22 min, reducing the time to less than 1 min/sample. Thus, the proposed auto-MSPE-ICP-MS method was successfully applied to analyze five heavy metals in cereals and feeds with a simple operation and high precision, safety, and reliability.

Separation and identification of ACE inhibitory peptides from lizard fish proteins hydrolysates by metal affinity-immobilized magnetic liposome

Purification of peptides responsible for angiotensin I-converting enzyme (ACE) inhibitory activity from highly complex protein hydrolysates is difficult. Affinity chromatography is a powerful method for purification of peptides. In this study, a metal affinity-immobilized magnetic liposome (MA-IML) was prepared using lipid, N-hexadecyl iminodiacetic acid (HIDA) and magnetic nanoparticles made of FeCl₃·6H₂O and FeCl₂·4H₂O as main materials. MA-IML was used to adsorb ACE inhibitory peptides from lizard fish proteins hydrolysates. The optimal pH of adsorption solution was 8.5. The peptide sample adsorbed by MA-IML was separated by reverse phase-high performance liquid chromatography (RP-HPLC). Upon amino acid sequence analysis and verification, an ACE inhibitory peptide with IC₅₀ value of 108 μM was identified to be VYP. Molecular docking results indicated that VYP bound to ACE via multiple binding sites. The present study demonstrated that MA-IML might be a useful tool for separating ACE inhibitory peptides from proteins hydrolysates.

Affinity Purification of Angiotensin Converting Enzyme Inhibitory Peptides from Wakame (Undaria Pinnatifida) Using Immobilized ACE on Magnetic Metal Organic Frameworks

Angiotensin-I-converting enzyme (ACE) inhibitory peptides derived from marine organism have shown a blood pressure lowering effect with no side effects. A new affinity medium of Fe3O4@ZIF-90 immobilized ACE (Fe3O4@ZIF-90-ACE) was prepared and used in the purification of ACE inhibitory peptides from Wakame (Undaria pinnatifida) protein hydrolysate (<5 kDa). The Fe3O4@ZIF-90 nanoparticles were prepared by a one-pot synthesis and crude ACE extract from pig lung was immobilized onto it, which exhibited excellent stability and reusability. A novel ACE inhibitory peptide, KNFL (inhibitory concentration 50, IC50 = 225.87 μM) was identified by affinity purification using Fe3O4@ZIF-90-ACE combined with reverse phase-high performance liquid chromatography (RP-HPLC) and MALDI-TOF mass spectrometry. Lineweaver-Burk analysis confirmed the non-competitive inhibition pattern of KNFL, and molecular docking showed that it bound at a non-active site of ACE via hydrogen bonds. This demonstrates that affinity purification using Fe3O4@ZIF-90-ACE is a highly efficient method for separating ACE inhibitory peptides from complex protein mixtures and the purified peptide KNFL could be developed as a functional food ingredients against hypertension.

Sub-Micromolar Pulse Dipolar EPR Spectroscopy Reveals Increasing CuII -labelling of Double-Histidine Motifs with Lower Temperature

Electron paramagnetic resonance (EPR) distance measurements are making increasingly important contributions to the studies of biomolecules by providing highly accurate geometric constraints. Combining double-histidine motifs with CuII spin labels can further increase the precision of distance measurements. It is also useful for proteins containing essential cysteines that can interfere with thiol-specific labelling. However, the non-covalent CuII coordination approach is vulnerable to low binding-affinity. Herein, dissociation constants (KD ) are investigated directly from the modulation depths of relaxation-induced dipolar modulation enhancement (RIDME) EPR experiments. This reveals low- to sub-μm CuII KD s under EPR distance measurement conditions at cryogenic temperatures. We show the feasibility of exploiting the double-histidine motif for EPR applications even at sub-μm protein concentrations in orthogonally labelled CuII -nitroxide systems using a commercial Q-band EPR instrument.

Synthesis of petal-like ferric oxide/cysteine architectures and their application in affinity separation of proteins

Petal-like ferric oxide/cysteine (FeOOH/Cys) architectures were prepared through a solvothermal route, which possessed high thiol group density. These thiol groups as binding sites can chelate Ni(2+) ions, which can be further used to enrich and separate his-tagged proteins directly from the mixture of lysed cells without sample pretreatment. These results show that the FeOOH/Cys architectures with immobilized Ni(2+) ions present negligible nonspecific protein adsorption and high protein adsorption capacity, with the saturation capacity being 88mg/g, which are especially suitable for purification of his-tagged proteins.

Ferroferric oxide/l-cysteine magnetic nanospheres for capturing histidine-tagged proteins

Ferroferric oxide/l-cysteine (Fe₃O₄/Cys) nanospheres (NSs) have been successfully synthesized via a facile solvothermal route. Fe₃O₄/Cys NSs possessed high thiol group density and saturation magnetization (M_s) of 84.6 emu g^-1. The prepared magnetic NSs are biocompatible and manipulatable by an external magnetic force. After chelating Ni²⁺ ions, Fe₃O₄/Cys-Ni²⁺ NSs were used to enrich and purify histidine-tagged (His-tagged) proteins directly from the mixture of lysed cells without pretreatment. It has been found that Fe₃O₄/Cys-Ni²⁺ NSs present negligible nonspecific protein adsorption and high protein binding activity with the saturation capacity being 53.2 μg mg^-1 and they are especially suitable for rapid purification of His-tagged proteins.

[Protocols of proteins interactomics: molecular fishing on optical chips and magnetic nanoparticles]

Now it is absolutely clear, that the majority of proteins in living systems function due to interaction with each other in stable or dynamic proteins complexes. Therefore necessity of deeper studies of proteins functions causes expansion of protein-protein interaction research. In the present review the brief description and comparative estimation of experimental methods and protocols of protein interactomics, based on technology of molecular fishing on an optical chips and paramagnetic nanoparticles is given.

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.

Profiling and quantitative evaluation of three nickel-coated magnetic matrices for purification of recombinant proteins: helpful hints for the optimized nanomagnetisable matrix preparation

Background

Several materials are available in the market that work on the principle of protein magnetic fishing by their histidine (His) tags. Little information is available on their performance and it is often quoted that greatly improved purification of histidine-tagged proteins from crude extracts could be achieved. While some commercial magnetic matrices could be used successfully for purification of several His-tagged proteins, there are some which have been proved to operate just for a few extent of His-tagged proteins. Here, we address quantitative evaluation of three commercially available Nickel nanomagnetic beads for purification of two His-tagged proteins expressed in Escherichia coli and present helpful hints for optimized purification of such proteins and preparation of nanomagnetisable matrices.

Results

Marked differences in the performance of nanomagnetic matrices, principally on the basis of their specific binding capacity, recovery profile, the amount of imidazole needed for protein elution and the extent of target protein loss and purity were obtained. Based on the aforesaid criteria, one of these materials featured the best purification results (SiMAG/N-NTA/Nickel) for both proteins at the concentration of 4 mg/ml, while the other two (SiMAC-Nickel and SiMAG/CS-NTA/Nickel) did not work well with respect to specific binding capacity and recovery profile.

Conclusions

Taken together, functionality of different types of nanomagnetic matrices vary considerably. This variability may not only be dependent upon the structure and surface chemistry of the matrix which in turn determine the affinity of interaction, but, is also influenced to a lesser extent by the physical properties of the protein itself. Although the results of the present study may not be fully applied for all nanomagnetic matrices, but provide a framework which could be used to profiling and quantitative evaluation of other magnetisable matrices and also provide helpful hints for those researchers facing same challenge.

Photocatalytic degradation of p-phenylenediamine with TiO2-coated magnetic PMMA microspheres in an aqueous solution

This study investigates the photocatalytic degradation of p-phenylenediamine (PPD) with titanium dioxide-coated magnetic poly(methyl methacrylate) (TiO2/mPMMA) microspheres. The TiO2/mPMMA microspheres are employed as novel photocatalysts with the advantages of high photocatalytic activity, magnetic separability, and good durability. The scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and transmission electron microscopy (TEM) images of the TiO2/mPMMA microspheres are used to characterize the morphology, element content, and distribution patterns of magnetite and TiO2 nanoparticles. The BET-specific surface area and saturation magnetization of the TiO2/mPMMA microspheres are observed as 2.21 m(2)/g and 4.81 emu/g, respectively. The photocatalytic degradation of PPD are performed under various experimental conditions to examine the effects of initial PPD concentration, TiO2/mPMMA microsphere dosage, and illumination condition on the eliminations of PPD and chemical oxygen demand (COD) concentrations. Good repeatability of photocatalytic performance with the use of the TiO2/mPMMA microspheres has been demonstrated in the multi-run experiments. The photocatalytic kinetics for the reductions of PPD and COD associated with the initial PPD concentration, UV radiation intensity, and TiO2/mPMMA microsphere dosage are proposed. The relationships between the reduction percentages of COD and PPD are clearly presented.

A New Metal Chelate Affinity Adsorbent for Cytochrome c

We have prepared a novel metal-chelate adsorbent utilizing N-methacryloyl-L-histidine methyl ester (MAH) as a metal-chelating ligand. MAH was synthesized by using methacryloyl chloride and l-histidine methyl ester dihydrochloride. Spherical beads with an average diameter of 75-125 microm were produced by suspension polymerization of 2-hydroxyethyl methacrylate (HEMA) and MAH carried out in an aqueous dispersion medium. Then, Cu(2+) ions were chelated directly on the chelating beads. Cu(2+)-chelated beads were used in the adsorption of cytochrome c (cyt c) from aqueous solutions. The maximum cyt c adsorption capacity of the Cu(2+)-chelated beads (658.2 micromol/g Cu(2+) loading) was found to be 31.7 mg/g at pH 10 in phosphate buffer. The nonspecific cyt c adsorption on the naked PHEMA beads was 0.2 mg/g. Cyt c adsorption increased with increasing Cu(2+) loading. Cyt c adsorption capacity was demonstrated for the buffer types with the effects in the order phosphate > HEPES > MOPS > MES > Tris-HCl. Cyt c molecules could be adsorbed and desorbed five times with these adsorbents without noticeable loss in their cyt c adsorption capacity.

Preparation and characterization of thermosensitive PNIPAA-coated iron oxide nanoparticles

A new and facile approach was established to fabricate thermoresponsive poly(N-isopropylacrylamide) (PNIPAA) coated iron oxide nanoparticles in a non-aqueous medium. The morphology and structure of the nanoparticle-doped composite were analyzed by means of transmission electron microscopy (TEM), x-ray powder diffraction (XRD), and Fourier transformation infrared spectrometry (FTIR). The thermosensitivity of the composite was also investigated. Results indicated that the oil-soluble iron oxide nanoparticles encapsulated with PNIPAA, composed of an inorganic iron oxide core and biocompatible PNIPAA shell, were dispersed well in water and had a sphere-like shape. The PNIPAA-coated iron oxide nanoparticles with such a kind of core-shell structure showed excellent thermosensitivity. Namely, the aqueous suspension of PNIPAA-coated iron oxide nanoparticles dramatically changed from transparent to opaque as the temperature increased from room temperature to 38 °C, showing potential as optical transmittance switch materials and their significance in the fields of protein adsorption and purification controlled release, and drug delivery.

Improving immunobinding using oriented immobilization of an oxidized antibody

Recent technical advances in biorecognition engineering and microparticle fabrication enabled us to develop a single-step purification process using magnetic particles (MPs). The process is simple, efficacious, easy to automate, and economical. The method immobilizes the ligand molecule in a particular orientation on commercial MPs that have surface carboxyl groups. Mouse IgG and anti-mouse IgG antibody were the model capture and ligand molecules for this study. The immunobinding efficacy of anti-mouse IgG antibody using "oriented immobilization" was compared with the efficacy of a conventional amine-coupling system that results in random orientation and of another standard method, the biotin-streptavidin system. The oriented immobilization was accomplished by oxidizing the sugar moiety in the CH(2) domain of the antibody's Fc and covalently conjugating the moiety to the hydrazine-coated MP. The specific binding affinity of the oriented immobilization process was about 2.5 times that of the amine-coupling system, and selectivity from a binary mixture was about 2 times greater for the oriented immobilization method. Results were nearly identical for the biotin-streptavidin system and the oriented immobilization system, matching the calculated binding stoichiometry between mouse IgG and anti-mouse IgG antibody. The binding improvement over the amine-coupling system shown by assay was confirmed by a separate surface plasmon resonance experiment. In summary, the oriented immobilization method was as effective as the streptavidin-biotin system, yet simpler and cost-effective.

Preparation and properties of magnetic nano- and microsized particles for biological and environmental separations

The paper presents a critical overview on magnetic nanoparticles and microspheres used as separation media in different fields of chemistry, biochemistry, biology, and environment protection. The preparation of most widely used magnetic iron oxides in appropriate form, their coating or encapsulation in polymer microspheres, and functionalization is discussed in the first part. In the second part, new developments in the main application areas of magnetic composite particles for separation and catalytical purposes are briefly described. They cover separations and isolations of toxic inorganic and organic ions, proteins, and other biopolymers, cells, and microorganisms. Only selected number of relevant papers could be included due to the restricted extent of the review.

Preparation of novel immunomagnetic cellulose microspheres via cellulose binding domain-protein A linkage and its use for the isolation of interferon alpha-2b

We have developed a novel method for immobilizing antibodies onto magnetic cellulose microspheres (MCMS) using a cellulose binding domain-protein A (CBD-ProA) linkage. Biospecific connection between antibodies and MCMS exhibited significant advantages compared to chemical coupling, including convenient and simple preparation, elimination of toxic compounds, and highly efficient antibody utilization. To evaluate the application of this method, interferon alpha-2b (IFN alpha-2b) was chosen as a model target for detailed analysis of method parameters, such as protein adsorption, antibody efficiency, and reproducibility of the matrix. After optimization and characterization, IFN alpha-2b was successfully purified from crude cell lysate in a single step by cross-linked anti-IFN alpha-2b IgG protein A-CBD-MCMS, purifying 106.1 microg IFN alpha-2b/mL matrix, corresponding to a 13-fold increase over the chemical coupling method. Size-exclusion HPLC identified that the IFN alpha-2b isolated by this method had an overall purity of 95.5%, while immunological and biological assays showed an activity recovery of 91.9% and specific antiviral activity of 2.67 x 10(8)IU/mg. Overall, this study effectively illustrates the favorable qualities of this immobilization method with precisely defined properties that provide an attractive strategy for developing large-scale purification suitable for targeting compounds in highly complex samples.

Thermosensitive polymer (N-isopropylacrylamide) coated nanomagnetic particles: Preparation and characterization

Thermosensitive polymer coated nanomagnetic adsorbents were synthesized by seed polymerization using surface modified nanomagnetic particles as the seeds. The Fe3O4 nanomagnetic particles were prepared by chemical precipitation of Fe2+ and Fe3+ salts in the ratio of 1:2 under alkaline and inert condition. The surface of these particles was modified by surfactants to achieve stability against agglomeration. These stable particles were then polymerized using N-isopropylacrylamide (NIPAM) as the main monomer, methylene-bis-acrylamide as the crosslinker and potassium per sulfate as the initiator. The thermosensitive adsorbents were characterized by using transmission electron micrography (TEM) and vibrating sample magnetometer (VSM). TEM showed that the particle remained discrete with a mean diameter of 12 nm. Magnetic measurements revealed that the particles are superparamagnetic only with a decrease of magnetism after binding with the polymer due to the increase in surface spin disorientation. Pure Fe3O4 spinel structure of these nanoparticles was indicated by the X-ray diffraction (XRD) patterns. The polymerization of NIPAM with the surface modified nanomagnetic particles was confirmed by Fourier transform spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). In addition, the adsorption/desorption of BSA molecule on these thermosensitive nanoparticles was investigated as a function of temperature. More than 60% desorption efficiency was achieved under appropriate condition.

Thermosensitive-polymer-coated magnetic nanoparticles: Adsorption and desorption of Bovine Serum Albumin

Adsorption and desorption behavior of Bovine Serum Albumin (BSA) on surface-modified magnetic nanoparticles covered with thermosensitive polymer (PNIPAM) was investigated as a function of temperature, pH, and ionic strength. Functionalization of surface-modified magnetic particles was performed by seed polymerization using N-isopropylacrylamide (PNIPAM) as the main monomer. Characterization of these particles was carried out using transmission electron micrography (TEM), and vibrating sample magnetometry (VSM). The adsorption results exhibited both pH and temperature sensitivity. The results showed that the temperature effect on adsorption/desorption behavior was mainly dependent on the properties of the particles' surface. The effect of pH was also investigated and it was observed that a smaller amount of protein was adsorbed at higher pH because of the electrostatic repulsive force between protein molecules and latex particles. The maximum amount of protein was adsorbed near the isoelectric point of BSA. Desorption results showed that more protein was desorbed when adsorption was done at lower temperatures and desorption efficiency was found to be higher than 80%.

Preparation, characterization and surface study of poly-epsilon caprolactone magnetic microparticles

Magnetic microparticles (MMP) have shown to be applied in increasing applications in various fields of biotechnology and medicine. One of their most promising utilization is the magnetic resonance imaging (MRI) in which superparamagnetic substances as magnetite are used in a nanometric size (less than 30 nm) and encapsulated within locally injected biodegradable microparticles. In this paper, magnetite has been encapsulated in polymer-based microparticles. The MMP have been prepared by an emulsion evaporation method. The different parameters influencing the particles size were investigated. The size was found to decrease as the stirring speed or the stabilizer amount (to certain limit) increases. The encapsulation efficacy was more than 90% yielding a magnetite loading of up to 30%, w/w. The X-ray photoelectron spectroscopy (XPS) showed less than 2% of iron atoms at the microparticles surface. The zeta potential response of MMP towards pH variation was very similar to that of magnetite-free microparticles confirming the encapsulation of magnetite within the microparticles. X-ray diffraction assays showed that magnetite crystalline structure was conserved after emulsification and MMP formation. Vibration simple magnetometer (VSM) showed a superparamagnetic profile of the MMP with a magnetic saturation increasing with the increased magnetite amount in the microparticles. These magnetic microparticles can enable clinicians to control microparticles distribution after a local administration in tumors by MRI. They can also be administered to target a defined tumor area by focusing a magnetic field on the surfaces covering the cancerous tissue.

The affinity concept in bioseparation: Evolving paradigms and expanding range of applications

The meaning of the word affinity in the context of protein separation has undergone evolutionary changes over the years. The exploitation of molecular recognition phenomenon is no longer limited to affinity chromatography modes. Affinity based separations today include precipitation, membrane based purification and two-phase/three-phase extractions. Apart from the affinity ligands, which have biological relationship (in vivo) with the target protein, a variety of other ligands are now used in the affinity based separations. These include dyes, chelated metal ions, peptides obtained by phage display technology, combinatorial synthesis, ribosome display methods and by systematic evolution of ligands by exponential enrichment (SELEX). Molecular modeling techniques have also facilitated the designing of biomimetic ligands. Fusion proteins obtained by recombinatorial methods have emerged as a powerful approach in bioseparation. Overexpression in E. coli often result in inactive and insoluble inclusion bodies. A number of interesting approaches are used for simultaneous refolding and purification in such cases. Proteomics also needs affinity chromatography to reduce the complexity of the system before analysis by electrophoresis and mass spectrometry are made. At industrial level, validation, biosafety and process hygiene are also important aspects. This overview looks at these evolving paradigms and various strategies which utilize affinity phenomenon for protein separations.

Synthesis of tentacle type magnetic beads as immobilized metal chelate affinity support for cytochrome c adsorption

Magnetic poly(2-hydroxyethylmethacrylate) (mPHEMA) beads with an average diameter of 100-140 microm were produced by suspension polymerization in the presence of magnetite particles (i.e. Fe3O4). Specific surface area and average pore size of the magnetic beads was found to be 50 m2/g and 819 nm, respectively. Ester groups in the mPHEMA structure were converted to imine groups by reacting with poly(ethyleneimine) (PEI) in the presence of NaH. Amino (-NH2) content of PEI-attached mPHEMA beads was determined as 102 mg PEI/g. Then, Cu2+ ions were chelated on the magnetic beads in the range of 20-793 micromol Cu2+/g. Cytochrome c (cyt c) adsorption was performed on the metal chelating beads from aqueous solutions containing different amounts of cyt c at different pHs, Cu2+ loadings and temperatures. Cyt c adsorption on the mPHEMA/PEI beads was 4.6 mg/g. Cu2+ chelation increased the cyt c adsorption significantly (40.1 mg/g). Adsorption capacity increased with Cu2+ loading and then reached a saturation value. Cyt c adsorption decreased with increasing temperature. Cyt c molecules could be reversibly adsorbed and eluted ten times with the magnetic adsorbents without noticeable loss in their cyt c adsorption capacity. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. In the last part of this article, cyt c adsorption experiments were performed in a magnetically stabilized fluidized bed (MSFB) system at optimum conditions determined from the batch experiments. The adsorption capacity decreased significantly from 46.8 to 15.4 mg/g polymer with the increase of the flow-rate from 0.5 to 4.0 ml/min. The resulting magnetic chelator beads possessed excellent long-term storage stability.

SYNTHESIS AND CHARACTERIZATION OF DOUBLE SURFACTANT COATED MAGNETIC PARTICLES

The unique and novel physicochemical features of the nanosized magnetic particles, which are attained due to their size and shape morphology, have aggregated an interest in the fields of nanoscience and nanotechnology. In this work, magnetic particles coated with double-layer surfactants were prepared and characterized. The magnetic particles ( Fe3O4 ) were synthesized by chemical precipitation of Fe2+ and Fe 3+ salts (1:2 ratio) with ammonium hydroxide ( NH4OH ) under inert atmosphere at 80°C followed by resuspension of the nanoparticles in water using thiodiglycolic acid. This procedure produced Fe3O4 nanoparticles stabilized against agglomeration. The primary surfactant coated particles were further treated with 4-vinylaniline at 25°C for about thirty minutes. As –SH group in thiodiglycolic acid has greater affinity formagnetic surface, it is easily attached to the iron particles through bonding. Subsequently, the – NH2 functional group of 4-vinylaniline reacts with the acid group – COOH of the thiodiglycolic acid. The size and the distribution of these magnetic particles, their morphologies and magnetic properties were measured by Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM), respectively. TEM results show the formation of single domain nanoparticles of mean diameter of about 10 nm. The strength of the NH–CO bond was measured by FTIR (Bio-Rad), the vibration observed at a wavelength of 1613–1745 cm-1. Thermo gravimetric analysis (TGA) reveals the existence of two distinct layers of surfactants on the particle surface. These surface-modified nanomagnetic particles can further be coated with thermo-sensitive polymeric materials which may be used in separation and purification of bio-molecules.