Adsorption Of Bovine Hemoglobin Research Articles

Magnetic Dendritic Polymer Nanospheres for High-Performance Separation of Histidine-Rich Proteins.

Magnetic nanospheres are becoming a promising platform for a wide range of applications in pharmacy, life science, and immunodiagnostics due to their high surface area, ease of synthesis and manipulation, fast separation, good biocompatibility, and recyclable performance. In this work, an innovative and efficient method is developed by in situ reducing and growing Ni(OH)2 for the preparation of dendritic mesoporous nanocomposites of silica@Fe3O4/tannic acid@nickel hydroxide (dSiO2@Fe3O4/TA@Ni(OH)2). The flower-like nanospheres have good magnetic response, large surface area, and high histidine-rich protein (His-protein) purification performance. The dSiO2@Fe3O4/TA@Ni(OH)2 nanospheres were synthesized on the basis of a φ(NaSal/CTAB) of 1/1 and a mass of ferrous chloride tetrahydrate of 0.3 g, resulting in a saturation magnetization value of 48.21 emu/g, which means it can be collected within ∼1 min using a magnetic stand. Also, the BET test showed that the surface area is 92.47 m2/g and the pore size is ∼3.9 nm for dSiO2@Fe3O4/TA@Ni(OH)2 nanocomposites. Notably, the nickel hydroxide with unique flower-like structural features enables the combination of a large number of Ni2+ ions and His-proteins for high performance. The isolation and purification experiments of the synthesized dSiO2@Fe3O4/TA@Ni(OH)2 were performed by separating His-proteins from a matrix composed of bovine hemoglobin (BHb), bovine serum albumin (BSA), and lysozyme (LYZ). The result showed that the nanospheres have a high combination capacity of ∼1880 mg/g in a rapid equilibrium time of 20 min, which was selective for the adsorption of BHb. In addition, the stability and recyclability of BHb are 80% after seven cycles. Furthermore, the nanospheres were also used to isolate His-proteins from fetal bovine serum, proving its utility. Therefore, the strategy of separating and purifying His-proteins using dSiO2@Fe3O4/TA@Ni(OH)2 nanospheres is promising for practical applications.

Preparation of a silk fibroin/gelatin composite hydrogel for high-selectively adsorbing bovine hemoglobin

Hydrogels are widely used in biomedical applications and separation of biomolecules. However, they either share limited biocompatibility or possess poor mechanical properties. In this study, by integrating two natural polymers of silk fibroin and gelatin into one hydrogel under the assistance of the cross-linker genipin, a silk fibroin/gelatin composite hydrogel was prepared with a high selectivity, a good biocompatibility and a porous structure. The preparation conditions were optimized as SF solution concentration of 3.5 wt%, gelatin solution concentration of 7 wt%, genipin solution concentration of 5 mg mL-1, reaction time of 1 h at 50 °C, and freeze-defrost cycle of 3. Following the entanglement of silk fibroin and gelatin, the mechanical strength of the obtained natural polymer-based hydrogel was significantly improved to around 0.8 MPa at 80% compression. The obtained hydrogel showed high adsorbing selectivity toward bovine hemoglobin (BHb) with an adsorption capacity of 724.0 mg g-1 at the BHb initial concentration of 0.5 mg mL-1, a 24.0-folder higher than that of BSA. The selectivity factor of BHb from BHb/BSA mixtures was also as high as 13.9. The adsorption isotherm and kinetics study indicated the obtained SF/G-G hydrogel possessed heterogeneous adsorption sites, the BHb adsorption process was chemisorption and diffusion-controlled, the increasing of temperature contributed to the adsorption process. The obtained hydrogel demonstrated the superiority and the valuable application prospect on selectively adsorbing BHb.

Selective Adsorption and Separation of Proteins by Ligand-Modified Nanofiber Fabric.

Electrospun polyvinyl alcohol (PVA) nanofiber fabric was modified by Cibacron Blue F3GA (CB) to enhance the affinity of the fabric. Batch experiments were performed to study the nanofiber fabric’s bovine hemoglobin (BHb) adsorption capacity at different protein concentrations before and after modification. The maximum BHb adsorption capacity of the modified nanofiber fabric was 686 mg/g, which was much larger than the 58 mg/g of the original fabric. After that, the effect of feed concentration and permeation rate on the dynamic adsorption behaviors for BHb of the nanofiber fabric was investigated. The pH impact on BHb and bovine serum albumin (BSA) adsorption was examined by static adsorption experiments of single protein solutions. The selective separation experiments of the BHb–BSA binary solution were carried out at the optimal pH value, and a high selectivity factor of 5.45 for BHb was achieved. Finally, the reusability of the nanofiber fabric was examined using three adsorption–elution cycle tests. This research demonstrated the potential of the CB-modified PVA nanofiber fabric in protein adsorption and selective separation.

A molecularly imprinted polymer based on MOF and deep eutectic solvent for selective recognition and adsorption of bovine hemoglobin.

In this study, a novel kind of imprinted polymers based on metal-organic frameworks (MOF@DES-MIPs) was prepared, using bovine hemoglobin (BHb) as template molecules and deep eutectic solvents (DES) as functional monomers for selective recognition and adsorption of BHb. MOF were used as the substrates to improve the accessibility of imprinted sites and DES as the functional monomers to produce different forces for BHb to help the formation of imprinted sites. Imprinted polymer films were taken to provide analyte selectivity. The MOF@DES-MIPs prepared were characterized and evaluated by scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectrometer. We also investigated the influences of BHb concentration and adsorption time on the performance of MOF@DES-MIPs. The maximal adsorption capacity of MOF@DES-MIPs to BHb reached 151.28 mg g-1, and the MOF@DES-MIPs showed good selectivity and fast adsorption equilibrium, which might offer a novel method for the preparation and research of molecularly imprinted polymers of biomacromolecules. In addition, MOF@DES-MIPs were successfully applied in the selective recognition of BHb from a real bovine blood sample. Graphical abstract.

Bovine hemoglobin adsorption onto modified silica nanoparticles: Multi-spectroscopic measurements based on kinetics and protein conformation

Herein, the effects of bovine hemoglobin (BHb) binding to hydrophilic silica nanoparticles (SN1) and hydrophobic silica nanoparticles (SN2) were explored under physiological conditions. SEM and XRD were used to characterize silica nanoparticles (SNs). Zeta potential and DLS confirmed the formation of protein corona (PC), and SN2 showed more increase in their size after PC formation comparing with SN1. The adsorption isotherms were fitted well by the Freundlich model, and the kinetics tended to follow pseudo-second-order kinetics. Then, the second structure of BHb has been analyzed by UV–vis and FT-IR spectroscopy, which implied the impact of SN2 on the secondary structure of BHb was greater than that of SN1 on BHb. Moreover, fluorescence spectroscopy and Raman spectroscopy showed that SNs may induce heme degradation to form fluorescent heme product, resulting in increased fluorescence intensity. This investigation will be significant in exploring the toxicity profile of SNs for their in vivo.

Preparation of bovine hemoglobin surface molecularly imprinted cotton for selective protein recognition

Abstract We have developed a bovine hemoglobin (BHb) surface molecularly imprinted cotton based on degreasing cotton via surface imprinting technique for the efficient selective adsorption of BHb. The morphological structure of the samples was characterized by Scanning Electron Microscopy (SEM), and the chemical modification steps were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The maximum adsorption capacity of the molecularly imprinted cotton (MIC) and non-imprinted cotton (NIC) for BHb was 62.95 mg/g and 8.32 mg/g, respectively, at the optimum pH value of 6.2. The kinetics studies demonstrated that the adsorption follows a pseudo-first-order kinetic model. The adsorption isotherm analysis indicated that the Langmuir adsorption isotherm fits well with the adsorption equilibrium data. Also, the selective adsorption shows the MIC has a good selectivity for BHb. In addition, the assessment of the reusability of the MIC was tested for five successive cycles revealed no significant decrease of the adsorption capacity. Electrophoretic analysis suggests the MIC were successfully applied to capture template proteins from the bovine blood sample.

Adsorption of Bovine Hemoglobin by Sulfonated Polystyrene Nanospheres

AbstractIn this work, the authors attempted to present a detailed study on the adsorption of bovine hemoglobin (BHB) by sulfonated polystyrene nanospheres (SPS NSs). The adsorption characteristics including adsorption isotherms, kinetics and thermodynamics were studied in detail. The adsorption isotherms were better fitted by the Langmuir model, leading to a remarkable adsorption capacity of 2831.4 mg g−1. Such an adsorption capacity is among the highest values reported in the literature. The adsorption kinetics was analyzed by the pseudo‐first‐order, pseudo‐second‐order and intra‐particle diffusion equations. The thermodynamic parameters including binding site, binding affinity, and changes of enthalpy, entropy and Gibbs free energy were determined by isothermal titration calorimetry measurements. The electrostatic interaction of BHB and SPS NSs was identified as the major adsorption mechanism. The effects of solution pH, temperature and competitive metal ions in the adsorption process were studied. Based on the Arrhenius equation, the activation energy of the adsorption process was determined to be 2.34 kJ mol−1.

Binding interactions of MoS2 quantum dots with hemoglobin and their adsorption isotherms and kinetics in vitro

To elucidate the binding interaction and adsorption isotherms and kinetics of molybdenum disulfides quantum dots (MoS2 QDs) with bovine hemoglobin (BHB) in vitro, it is urgent to investigate their binding mechanism in this work. The experimental results indicated that MoS2 QDs partly induced denaturation and expansion of secondary structure of BHB and the microenvironment changes of heme by the ground state complex formation of BHB with MoS2 QDs. The tertiary structure and the thermal denaturation of BHB on MoS2 QDs surface are not obviously different from only BHB solution. The experimental results were verified correctness with molecular modeling analysis. The Soret band changes indicated that the presence of MoS2 QDs partly protects the oxidation process of BHB by H2O2. In addition, the kinetics of BHB adsorption onto MoS2 QDs follows the pseudo-second-order kinetic model with high adsorption capacity, their adsorption was a fast process. This in vitro study could act as a precedent in understanding the interaction mechanism of biomolecules with MoS2-based nanomaterials.

Peparation of Magnetic Nanoclusters for Efficient Selective Protein Adsorption

Event Abstract Back to Event Peparation of Magnetic Nanoclusters for Efficient Selective Protein Adsorption Fang Lan1, Qi Yang1, Yao Wu1* and Zhongwei Gu1* 1 Sichuan University, National Engineering Research Center for Biomaterials, China Introduction: The efficient adsorption of protein from a complex mixture is of great significance in proteomics and diagnostics. Magnetic nanoparticless have widely applied in the biomedical field especially in protein separation due to unique superparamagnetic property [1]. In order to selectively adsorption and separation target protein, antibody and other ligands were usually immobilized onto the surface of magnetic nanoparticles [2]. However, most ligands are either expensive or inconvenient to obtain. Although several clever strategies have been reported to resolve this problem, these systems still suffer from drawbacks including low magnetic content, low saturation magnetization, complicated synthesis routes, and severe aggregation of nanomaterials. Therefore, the development of a facile yet efficient strategy for selective proteinadsorption is highly desirable. Materials & Methods: We proposed a new kind of ligand-free Fe3O4/carboxymethylated chitosan (Fe3O4/CMCS) nanoclusters with high negative charges by a combination method of inverse emulsion crosslinking approach and assembly technique. Firstly, the Fe3O4 nanoparticles which were prepared by co-precipitation were stabled with CMCS to obtain Fe3O4/CMCS nanospheres as assembly units. Then, the Fe3O4/CMCS composite nanospheres were assemblied and cross-linked with genipin in liquid paraffin to successfully prepare Fe3O4/CMCS nanoclusters. To evaluate selective protein adsorption capacity of the ligand-free Fe3O4/CMCS nanoclusters without any further functionalization, lysozyme (LYZ), bovine serum albumin (BSA), bovine hemoglobin (BHB), apo-transferrin (TRT), myoglobin (MB) were used as model proteins. The ligand-free Fe3O4/CMCS nanoclusters were incubated with a protein mixture. For selective adsorption of BHB from biological samples, the ligand-free Fe3O4/CMCS nanoclusters were incubated with 10% fetal bovine serum (FBS) diluted with Dulbecco’s modified Eagle’s medium (DMEM) cell culture medium. Results & Discussion: The Fe3O4/CMCS nanoclusters presented a spherical shape of around 500 nm and the size distribution was narrow. The surface of the Fe3O4/CMCS nanoclusters had high negative charges at a wide pH ranging from pH 5-11, demonstrating stability of the Fe3O4/CMCS nanoclusters. Such nanoclusters exhibited superparamagnetism at room temperature due to negligible coercivity and remanence and high saturation magnetization. In suspension solution, the Fe3O4/CMCS nanoclusters could respond rapidly to the external magnet (about 200 mT) within 10 s and could be re-dispersed in water by gently shaking once the external magnet was removed. The results of protein experaments showed the ligand-free Fe3O4/CMCS nanoclusters could highly selectively adsorb BHB in a protein mixture. Moreover, the ligand-free Fe3O4/CMCS nanoclusters exhibted excellent BHB selective adsorption capacity in FBS. We futher studied the mechanism of high selective adsorption of BHB. Interestingly, we found that the ligand-free Fe3O4/CMCS nanoclusters could highly effectively selectively adsorb proteins structurally similar to BHB (e. g. chymotrypsin (CTP), lysozyme (LYZ)). Both the high negative charges on the surface of Fe3O4/CMCS nanoclusters and unique structure of proteins influence on highly selectively protein adsoption. Conclusions: We have successfully fabricated ligand-free high-magnetic-content Fe3O4/CMCS nanoclusters. The ligand-free magnetic nanoclusters possessed excellent properties would be used as a potential platform for selective protein adsorption.

Selective adsorption of bovine hemoglobin on functional TiO2 nano-adsorbents: surface physic-chemical properties determined adsorption activity

Surface functionalized nanoparticles are efficient adsorbents which have shown good potential for protein separation. In this work, we chose two different types of organic molecules, oleic acid (OA) and 3-glycidoxypropyltrimethoxy silane (GPTMS), to functionalize the surface of TiO2 nanoparticles, and we studied the effects of this modification on their surface physicochemical properties in correlation with their selective adsorption of proteins. The results showed that the surface zeta potential and the surface water wettability of the modified TiO2 were significantly changed in comparison with the original TiO2 nanoparticles. The adsorption activities of bovine hemoglobin (BHb) and bovine serum albumin (BSA) on these functionalized TiO2 samples were investigated under different conditions, including pH values, contact time, ion strength, and initial protein concentration. In comparison with the non-specific adsorption of original TiO2, however, both the OA–TiO2 and GPTMS–TiO2 exhibited increased BHb adsorption and decreased BSA adsorption at the same time. Using a binary protein mixture as the adsorption object, a higher separation factor (SF) was obtained for OA–TiO2 under optimum conditions. The different adsorption activities of BHb and BSA on the modified TiO2 were correlated with different interactions at the protein/solid interface, and the chemical force as well as the electrostatic force played an important role in the selective adsorption process.

The synthesis of imprinted polymers based on Fe3O4 nanomaterials and the recognition of proteins

A surface molecularly imprinted polymer (MIP-Fe3O4@AA) was prepared on a magnetic material (Fe3O4@AA) surface for the selective recognition and adsorption of bovine hemoglobin (BHb).

DEVELOPMENT OF MAGNETICALLY RESPONSIVE Fe3O4@C CORE/SHELL MICROSPHERES AS POTENTIAL VECTORS FOR DRUG-DELIVERY APPLICATIONS

The Fe3O4@C core/shell microspheres were fabricated via a two-step process. Fe3O4 microspheres were firstly prepared, and Fe3O4@C core/shell microspheres were subsequently fabricated using glucose as a carbon source by a hydrothermal route, in which the thickness of the carbon coating was about 20 nm. The resulting products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR). The Nitrogen adsorption–desorption isotherms reveal their mesoporous structure and larger BET surface area (62.3 m2g-1). The Fe3O4@C core/shell microspheres possess ferromagnetism and high saturation magnetization (39.2 emu ⋅ g-1). Bovine hemoglobin (BHb) was used as a model protein to test the adsorption and desorption properties of the Fe3O4@C core/shell microspheres. The capacity for BHb adsorption was more than 71.3 mg/g. According to the values obtained in the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay the Fe3O4@C core/shell microspheres show a low toxicity. Therefore, the prepared Fe3O4@C core/shell microspheres are of great significance for guided site-specific drug delivery.

In Situ Monitoring of Protein Adsorption on a Nanoparticulated Gold Film by Attenuated Total Reflection Surface-Enhanced Infrared Absorption Spectroscopy

In situ surface enhanced infrared absorption spectroscopy (SEIRAS) with an attenuated total reflection (ATR) configuration has been used to monitor the adsorption kinetics of bovine hemoglobin (BHb) on a Au nanoparticle (NP) film. The IR absorbance for BHb molecules on a gold nanoparticle film deposited on a Si hemispherical optical window is about 58 times higher than that on a bare Si optical window and the detection sensitivity has been improved by 3 orders of magnitude. From the IR signal as a function of adsorption time, the adsorption kinetics and thermodynamics can be explored in situ. It is found that both the electrostatic interaction and the coordination bonds between BHb residues and Au NP film surface affect the adsorption kinetics. The maximum adsorption can be obtained in solution pH 7.0 (close to the isoelectric point of the protein) due to the electrostatic interaction among proteins. In addition, the isotherm of BHb adsorption follows well the Freundlich adsorption model.

A Novel Method to Immobilize Magnetic Nanospheres with Metal Ions for the Adsorption of Bovine Hemoglobin

The magnetite (Fe3O4) nanoparticles with immobilized metal affinity ligands were prepared for protein adsorption. First, magnetite nanoparticles were synthesized by hydrothermal method. Charged with Zn2+, the magnetic nanospheres were applied to adsorb bovine hemoglobin (BHb). The morphology and magnetic properties of magnetic nanospheres were investigated by TEM. These magnetic nanospheres modified with metal ligands can be used efficiently in protein affinity separation and purification.

Immobilization of hemoglobin within channel of mesoporous TiO2-SiO2 composite

In this investigation, mesoporous TiO2-SiO2 composites with different Ti/Si molecular ratios were synthesized by one pot method. Apart from the characterization by small angle X-ray diffraction (SAXRD), transmission electron microscope (TEM) and N2 absorption-desorption isotherms, these mesoporous materials were used in the adsorption and enrich of biological molecules. The results demonstrate that TiO2-SiO2 composites possess the ordered mesoporous structure with uniform pore. Bovine hemoglobin (BHb) can be immobilized within the mesopore of the composite and the immobilization amount increases with the Ti/Si molecular ratio. It is speculated that the strong electrostatic interaction between biomolecule and the inner surface of mesoporous materials enhances the adsorption of BHb. Moreover, our investigation confirms that the absorbed BHb still effectively retains its bioactivity, which is very significant for the potential application of this hybrid material in biocatalysis.

Adsorption of Bovine Hemoglobin onto Spherical Polyelectrolyte Brushes Monitored by Small-Angle X-ray Scattering and Fourier Transform Infrared Spectroscopy

The adsorption of bovine hemoglobin (BHb) onto colloidal spherical polyelectrolyte brushes (SPBs) is studied by a combination of small-angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR). The SPBs consist of a polystyrene core onto which long chains of poly(styrene sulfonic acid) are grafted. Hemoglobin is a tetrameric protein that disassembles at low pH's and high ionic strengths. The protein is embedded into the brush layer composed of strong polyacids. Thus, the protein is subjected to a pH and ionic strength that largely differs from the bulk solution. At low ionic strengths up to 650 mg of BHb per gram of SPB could be immobilized. The analysis of the particles loaded with protein by SAXS demonstrates that the protein enters deeply into the brush. A large fraction of hemoglobin is bound at the surface of the polystyrene core. We attribute this strong affinity to hydrophobic interactions between the protein and the polystyrene core. The other protein molecules are closely correlated with the polyelectrolyte chains. The secondary structure of the protein within the brush was studied by FTIR spectroscopy. The analysis revealed a significant disturbance of the secondary structure of the tetrameric protein. The content of alpha-helix is significantly lowered compared to the native conformation. Moreover, there is an increase of beta-sheet structure as compared to the native conformation. The partial loss of the structural integrity of the hydrophobic protein is due to hydrophobic interactions with the hydrophobic polystyrene core. Hydrophobic interactions with the phenyl groups of the poly(styrene sulfonate) chains influence the secondary structure as well. These findings indicate that changes of the secondary structure play a role in the uptake of hemoglobin into the poly(styrene sulfonate) brushes.

Bovine hemoglobin adsorption onto polymer latices

The adsorption behavior of bovine hemoglobin (BHb) onto polymer latices was investigated. The latices used were hydrophobic polystyrene (PS) and hydrophilic copolymers; i.e., styrene (St)/2-hydroxyethyl methacrylate (HEMA) copolymer [P(St/HEMA)] and styrene/acrylamide (AAm) copolymer [P(St/AAm)]. All the latices were prepared without emulsifier and were highly monodisperse. From the measurement results of the surface characteristics for the latices, it was found that the hydrophilic diffuse layers of poly-HEMA and poly-AAm existed on the surfaces of P(St/HEMA) and P(St/AAm) latex particles, respectively. The initial slopes of the adsorption isotherms were greatly affected by pH change. The amount adsorbed onto the latices, except that onto copolymer latices at ionic strength 0.1, showed a maximum near the isoelectric point (iep, pH about 6.8) of BHb. These tendencies in BHb adsorption were similar to those in bovine serum albumin (BSA) adsorption. However, in the regions of pH < 4 and pH > 11, the amount of BHb adsorbed onto PS latex increased again. It was suggested that this re-increase in the amount adsorbed was correlated to the dissociation of BHb (tetramer) into its subunits (dimer and/or monomer) in these pH regions. Moreover, at a lower ionic strength (0.001), the BHb molecule showed a rather high adsorption onto PS latex even in the alkaline pH region. These results indicate that the BHb molecule has a stronger affinity for hydrophobic surfaces than the BSA molecule has. The amounts of BHb adsorbed onto hydrophilic copolymer latices were much smaller than that onto PS latex except in the iep region of the protein.