Adsorption Capacity Of Bovine Serum Albumin Research Articles

Ultrasonic assisted removal of methyl orange and bovine serum albumin from wastewater using modified activated carbons: RSM optimization and reusability

Abstract The removal of industrial pollutants from water remains a significant challenge in water treatment processes. This study investigated the efficacy of powder-activated carbon (PAC), thermally modified PAC (TPAC), and chemically modified PAC (CPAC) for removing bovine serum albumin (BSA) and methyl orange (MO) from simulated wastewater. After undergoing treatment, the BET surface area of TPAC increased to 823 m2/g, while that of CPAC increased to 657 m2/g compared to the initial surface area of pristine PAC, which was 619 m2/g. Batch adsorption experiments assisted by ultrasonication were conducted to evaluate the impact of solution pH, initial concentration, and contact time on the adsorption capacities (qmax) of BSA and MO. TPAC demonstrated superior performance, achieving qmax values of 152 mg/g for MO and 133 mg/g for BSA, compared to PAC, which provided qmax values of 124 mg/g and 112 mg/g for BSA, respectively. Furthermore, pH levels of 3 and 5 were identified as highly effective for the removal of MO and BSA from water, respectively. The adsorption kinetics of both MO and BSA followed pseudo2nd-order (R2 > 0.99) reaction kinetics under both batch and ultrasonic conditions, confirming the removal of contaminants through chemisorption. The adsorption trends also satisfied the Langmuir isothermal model, indicating the formation of a uniform monolayer during the adsorption process of these contaminants. To understand the simultaneous effect of all the variables, response surface methodology (RSM) using central composite design (CCD) was used to predict the adsorption capacities of CPAC. After five adsorption cycles, the removal efficiencies of MO (from 98% to 80%) and BSA (from 55% to 40%) decreased in the CPAC system. The results suggested that CPAC can be effectively utilized to remove MO from wastewater.

Fluorescence study of the interaction between albumin and layered double hydroxides

Layered double hydroxides nanoparticles (LDH-NP) are increasingly studied for biomedical applications. Nevertheless, their interaction with biomolecules such as proteins needs further exploration for an effective application. In this work, the adsorption of bovine serum albumin (BSA) on LDH-NP and the conformation changes of the protein upon adsorption were characterized using fluorescence spectroscopy. First, the quenching of tryptophan residues of BSA by chloride-intercalated LDH-NP was explored and the BSA adsorption capacity of LDH-NP were determined. Then, the structural conformation of the protein was analyzed by fluorescence spectroscopy (including synchronous, polarization and quenching studies) at different surface coverages. Finally, the proclivity of adsorbed BSA molecules to assemble as amyloid fibril was evaluated. Due to the positive charging and low curvature of LDH-NP, BSA molecules were strongly adsorbed, which produced a quenching of the protein fluorescence and a large adsorption capacity. The effect on BSA conformation was dependent on surface coverage (SC): at low values ,t he tryptophan residues were in more hydrophobic environments and more accessible to quenchers than al high ones. At low SC, there is space between the BSA molecules to spread on the surface, which led to a conformation change. Contrarily, the native conformation around tryptophan residues of BSA was preserved at high SC due to the tight packing of the adsorbed protein molecules. As a result, BSA molecules are stabilized against the formation of amyloid fibrils at high SC, while at low SC they present a similar fibrillation than free BSA.

Modelling and optimization of bovine serum albumin adsorption on calcium bentonite using box-behnken experimental design method

The purpose of this study is to investigate and optimize the process parameters for bovine serum albumin (BSA) adsorption onto calcium bentonite (CaB) using the Box-Behnken experimental design method. Calcium bentonite was characterized using FT-IR, SEM, XRD, zeta potential measurements, and Boehm titration methods. The BSA adsorption capacity of calcium bentonite was modelled with respect to pH (2.8, 4.8, and 6.8), temperature (25 °C, 32.5 °C, and 40 °C), and initial protein concentration (0.1–1.2 mg ml−1) using the Box-Behnken experimental design method. The Design Expert 13.0 software was used to optimize the process conditions and obtain three-dimensional response surface graphs. A regression model, which gives the relationship between the process parameters and BSA adsorption capacity, was obtained using Design Expert software. The developed model showed that the most effective parameter on adsorption was the initial protein concentration followed by pH and temperature. The maximum adsorption capacity was obtained about 171 mg/g under optimal conditions (pH 4.8, 40 °C, and 1 mg ml−1 of initial BSA concentration). BSA adsorption onto CaB fit the pseudo-second order kinetic model. This study showed that process parameters for BSA adsorption can be effectively investigated and optimized using the Box-Behnken experimental design method with a fewer number of experiments.

Synthesis of a gelatin based molecularly imprinted hydrogel with high selectivity on adsorbing bovine serum albumin

Molecularly imprinted polymers are confronted with many challenges during application to separating proteins, this study synthesized a molecularly imprinted hydrogel (MIP hydrogel) for specifically separating bovine serum albumin (BSA) with high selectivity. By using the ionic liquid [VAFMIM]Cl as the structure functional monomer and N-isopropylacrylamide (NIPAM) as the thermo-sensitive functional monomer, the obtained gelatin based MIP hydrogel was porous, showed good mechanical properties and outstanding swelling ability. The methacrylation of gelatin improved the MIP hydrogel greatly on mechanical strength. The employment of NIPAM enabled the obtained MIP hydrogel thermo-responsive on swelling ability and adsorption capacity. The BSA adsorption capacity of MIP hydrogel was as high as 150.18 mg/g when the BSA initial concentration was used at 0.5 mg/mL, and the imprinting factor of MIP hydrogel was achieved as high as 5.17. The selectivity coefficients against bovine hemoglobin and lysozyme achieved as high as 11.83 and 9.39, respectively. In BSA/BHb mixture, the MIP hydrogel separation factor toward BSA was still as high as 23.97, and the MIP hydrogel adsorption capacity toward BSA was 4.64-fold larger than that of NIP hydrogel. The adsorption kinetics and isotherm study demonstrated the surface of the synthesized MIP hydrogel was homogenous, the adsorbing active sites were identical with equal energy, the BSA molecules were adsorbed monolayer on MIP hydrogel, the adsorption process was chemisorption and diffusion-controlled. The prepared MIP hydrogel was favorable and showed high potentiality on specific separation of BSA.

Adsorption of BSA Protein in Aqueous Medium Using Vegetable Tannin Resin from Acacia mearnsii (Mimosa) and Modified Lignocellulosic Fibers from the Bark of Eucalyptus citriodora.

Proteins are abundant biomolecules found in human cells, as well as pathogenic bacteria and viruses. Some of them become pollutants when released into water. Adsorption is an advantageous method for separating proteins in aqueous media since proteins are already immobilized on solid surfaces. Adsorbents with surfaces rich in tannins are efficient due to their affinity for strong interactions with the various amino acids that make up proteins. This work aimed to develop an adsorbent for protein adsorption in aqueous medium using lignocellulosic materials modified from eucalyptus bark and vegetable tannins. A more efficient resin was prepared containing 10% eucalyptus bark fibers and 90% tannin mimosa by condensation with formaldehyde, and it was characterized by UV–Vis, FTIR-ATR spectroscopy and determinations of degree of swelling, bulk and bulk density and specific mass. For UV–Vis spectroscopy the percentage of condensed and hydrolysable tannins in the extracts of fibers of the dry husks of Eucalyptus Citriodora was estimated and it was also determined your soluble solids. The study of bovine serum albumin (BSA) adsorption was carried out in batch with quantification by UV–Vis spectroscopy. The most efficient prepared resin obtained 71.6 ± 2.78% removal in a solution of 260 mg L−1 of BSA working in a better pH range of the aqueous solution of BSA in its isoelectric point, ~ 5, 32 ± 0.02, under these conditions, the synthesized resin can reach a maximum BSA adsorption capacity of ~ 26.7 ± 0.29 mg g−1 in 7 min. The new synthesized resin presents good prospects for adsorption of proteins or species that in their structure have higher percentages of amino functional groups or amino acids with aliphatic, acidic and/or basic hydrophilic characteristics.

CO2 and Magnetic Dual-Responsive Microspheres That Reversibly and Selectively Capture Target Proteins under Mild Conditions

CO2-responsive polymers transform from hydrophobic to hydrophilic under a gas stimulus, which can be used to capture proteins under mild conditions; however, the selectivity is not high enough. In this work, Fe3O4 enveloped with silicon dioxide (SiO2) was prepared and grafted on poly(2-(diethylamino)ethyl methacrylate) (PDEA) through the atom transfer radical polymerization (ATRP) technique, yielding a CO2-responsive magnetic microsphere. The molecularly imprinted surface was then fabricated using poly(dopamine) (PDA) with bovine serum albumin (BSA) as a template, producing gas and magnetic dual-responsive microspheres with good selectivity, denoted as Fe3O4/SiO2/PDEA-MIP. Their chemical structure and CO2 responsiveness were confirmed. Their adsorption capacity for BSA was 55 mg g–1 under the concentration of 0.8 mg mL–1 with good reversibility. The imprinting factor (IF) reached as high as 5.73 under optimized adsorption conditions, which further makes it specifically capture the target protein from a mixture and separate the protein under gas or magnetic control. The interaction between BSA with unprotonated and protonated PDEA was theoretically studied by quantum mechanics calculations, which prove its reversibility under the CO2 stimulus. Furthermore, the circular dichroism (CD) spectra approved that the conformation of proteins remained unchanged under the CO2 stimulus, indicating that it is a moderate separation technique for proteins. This work supplied a strategy to develop highly selective and switchable materials to realize protein recognition and separation under mild conditions.

Multiphase zinc and magnesium mono-substituted calcium phosphates derived from cuttlefish bone: A multifunctional biomaterials

Biomimetic calcium phosphate (CaP) systems mono-substituted with zinc (Zn2+) and magnesium (Mg2+) ions were prepared from a biogenic source (cuttlefish bone) by wet precipitation method. The results revealed that the as-prepared powders were composed of calcium-deficient carbonated hydroxyapatite (HAp), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP), while the heat-treated powders consisted of HAp, α-tricalcium phosphate (α-TCP), and β-tricalcium phosphate (β-TCP). In addition to Zn2+ and Mg2+ ions, the presence of CO32−, Sr2+ and Na + ions was detected with elemental analysis, which can be attributed to the use of cuttlefish bone as a natural precursor of Ca2+ ions. The data obtained by XRD study demonstrated the decrease in lattice parameters in the OCP and β-TCP phases for Zn-substitution and Mg-substitution in the HAp, OCP, and β-TCP phases. Zn2+ occupies the Ca(1,3,4,6,7,8) sites in OCP and Ca(1,2,3,4) sites in β-TCP, while Mg2+ occupies the Ca(2) sites in HAp and the Ca(4,5) sites in β-TCP. Phase transformation study under simulated physiological conditions for 7 days showed the transformation of OCP and ACP into the thermodynamically more stable HAp. Characterization of the zeta-potential showed positively charged populations for all prepared CaP powders, while all samples showed high bovine serum albumin adsorption capacity. The culture of human embryonic kidney cells showed that the prepared CaPs are non-cytotoxic and that viability of the cells increases during the culture period. All powders obtained showed antibacterial activity towards Gram-negative Escherichia coli and low antibacterial effect against Gram-positive Staphylococcus aureus, as determined by viability analysis during 48 h. Inhibition zone analysis and observation of the morphology after 24 h showed no antibacterial properties.

Anti‐nonspecific adsorption segments‐assisted self‐driven surface imprinted fibers for efficient protein separation

AbstractAt present, the development of high‐performance protein imprinted materials is still a research hotspot in the field of protein imprinting. Herein, anti‐protein adsorption segment (CBMA)‐assisted self‐driven bovine serum albumin (BSA) surface imprinted fibers MTCFs@SIP@CBMA with high recognition selectivity are pioneered using the strategies of combining magnetic nanomaterial surface imprinting technique with amino‐Michael addition. The special structure of the carrier MTCFs endows MTCFs@SIP@CBMA with magnetic performance and self‐driven adsorption performance, which simplifies the separation process while improving the adsorption capacity and accelerating the adsorption rate. The adsorption capacity for BSA reached 390 ± 20 mg/g within 30 min. The introduction of CBMA segments on the surface after imprinting by amino‐Michael addition makes its polymer chain length and position controllable. Under the strongest anti‐nonspecific adsorption effect, MTCFs@SIP@CBMA exhibit excellent specific identification to BSA from mixed proteins. Additionally, MTCFs@SIP@CBMA show considerable reusability. Therefore, MTCFs@SIP@CBMA are expected to be applied in efficient separation of proteins in biological samples.

Adsorption characteristics of bovine serum albumin onto α-Fe2O3 nanoparticles prepared via the alcohol solution combustion process of ferric nitrate

The α-Fe2O3 nanoparticles were prepared via the alcohol solution combustion process of ferric nitrate. The scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS). X-ray diffraction (XRD), and vibrating sample magnetometer (VSM) were taken to characterize the prepared α-Fe2O3 nanoparticles. The average particle sizes of the as-prepared α-Fe2O3 nanoparticles were approximately 180 nm, and their magnetic property was approximately 0.42 emu·g−1 after the measurement. The different concentrations of BSA solutions and the adsorption times were investigated to investigate the adsorption characteristics of bovine serum albumin (BSA) onto α-Fe2O3 nanoparticles. For larger adsorption capacity and higher removal rate, the dose of α-Fe2O3 nanoparticles in aqueous solution was selected at 2.5 mg·ml−1. The adsorption process of BSA onto α-Fe2O3 nanoparticles conformed to the pseudo-first-order kinetic model. While, the correlation coefficient (R2) of the Temkin isothermal model was higher than Langmuir model and Freundlich isothermal model, suggesting that the isothermal model of BSA onto α-Fe2O3 nanoparticles was more in line with Temkin isotherm model. Which suggested that the adsorption behavior of magnetic α-Fe2O3 nanoparticles for BSA belonged to multi-molecular layer chemisorption. When BSA concentration was 600 mg·l−1 and the pH of solution was 5, the adsorption capacity of BSA onto magnetic α-Fe2O3 nanoparticles achieved 114.2 mg·g−1, and the adsorption rate could still reach 70.3% of the first time after 7 cycles.

Preparation and characterization of agarose-encapsulated ceramic hydroxyapatite particles for flow-through chromatography

ABSTRACT Composite adsorbents were prepared by encapsulating ceramic hydroxyapatite particles (CHT Type I) within inert agarose beads using an emulsion method as stationary phases for the removal of small protein and nucleic acid impurities from large proteins and bioparticles in a flow-through mode. The composite particles were prepared with 6% and 10% agarose and contain 35% and 25% (v/v) CHT, respectively, with effective pore radii of 15.1 and 8.8 nm. The functional properties were studied using yeast RNA, bovine serum albumin (BSA), thyroglobulin (Tg), IgM, and 30 and 50 nm silica nanoparticles (NP) as models. The RNA and BSA adsorption capacities are smaller than for unencapsulated CHT on a bead volume basis but comparable when normalized by the volume of CHT particles in the composite beads attaining values between 30 and 40 mg/mL. Confocal laser scanning microscopy shows that, while RNA and BSA have complete access to the encapsulated CHT particles, Tg, IgM, and the NPs are largely excluded. RNA and BSA breakthrough experiments in laboratory-scale columns at a 5-min residence time show RNA and BSA binding capacities comparable to those measured in a batch mode with either single component feeds or with feed mixtures containing 30 nm NPs.

PH and temperature dual-sensitive molecular imprint polymers for BSA based on Cu2+ coordination

A novel kind of pH and temperature dual-sensitive Molecular imprint polymers (MIPs) combined with Cu2+ coordination (SiO2@CS/NIPAM-Cu2+-MIP) has been synthesized using glycidyl methacrylate-iminodiacetic acid (GMA-IDA) as a metalchelating ligand, with bovine serum albumin (BSA) as template protein, combined with pNIPAM and chiston (CS) as temperature and pH sensitive monomers, respectively. The coordination effect of GMA-IDA-Cu2+ has been shown to be beneficial to improve the adsorption capacity and adsorption specificity of BSA. The influence of pH not only changed the charge force between the polymer and protein in the imprinting system, but also deformed the imprinting cavity through the protonation of NH3+ on CS. Further, the thermo-sensitivity of the imprinted polymer was also found to be satisfactory. Withthe joint efforts of coordination, electrostatic action and good matching of imprinted sites, higher adsorption capacity (173.48 mg∙g-1) and imprinting factor (2.72) have been obtained at pH 4.6 and 35ºC. Although it took about 4 h to reach saturation adsorption, the cyclability of the SiO2@CS/NIPAM-Cu2+-MIP was found to be acceptable and the adsorptioncapacity was maintained at original 81.16% after six cycles. It is for the first time that GMA-IDA-Cu2+ has been used to prepare the pH and temperature dual-sensitive imprinted polymer for BSA.

Improved antibody adsorption performance of phenyl-based mixed-mode adsorbents by adjusting the functional group of ligand

The present work is aimed to improve the antibody adsorption performance of phenyl-based mixed-mode adsorbents by adjusting the functional group of ligand. Two new mixed-mode adsorbents coupled with 4-(aminomethyl)phenol (AMP) and 4-(aminomethyl)benzonic acid (AMA) were designed based on the structure of benzylamine (BA), where a hydroxyl or carboxyl group was introduced. Bovine serum Immunoglobulin G (IgG) and bovine serum albumin (BSA) were used as the model proteins. The adsorption isotherms of IgG and BSA were investigated at different pH values ranging from 4.0–8.9 to evaluate the adsorption performance, and protein-ligand molecular interactions were explored through addition of sodium chloride and glycerol. The results showed that both of adsorbents coupled with AMP or AMA had lower saturated binding capacities (Qm) towards BSA and higher adsorption capacity ratio of IgG to BSA when compared to BA-based adsorbents. The contributions of electrostatic interactions and hydrophobic interactions to proteins binding were different among these phenyl-based mixed mode adsorbents. Finally, AMP-based adsorbent possessing high adsorption capacity ratio of IgG to BSA and salt tolerance was selected to separate IgG from mimetic serum with purity higher than 96 %. The results indicated adjusting the functional groups of ligand to regulate the electrostatic and hydrophobic interactions of protein-ligand was useful to improve the antibody separation performance of mixed-mode adsorbents.

Highly Efficient Adsorption of Bilirubin by Ti3 C2 Tx MXene.

We discovered that the 2D Ti3 C2 Tx MXene sheet displays an ultra-high removal capability for bilirubin (BR). In particular, MXene shows 47.6 times higher removal efficiency over traditional activated carbon absorbents. The effect of MXene on the removal rate of BR in BR solution containing different concentrations of bovine serum albumin (BSA) was studied. The adsorption capacity of BSA for BR at high concentration of 5 g L-1 was about 85% of the best adsorption capacity. The MXene before and after adsorption was characterized by SEM, FT-IR and XPS. Furthermore, MXene beads were prepared, and the hemoperfusion simulation experiment was carried out. The results show that the adsorption capacity of MXene for bilirubin can reach 1192.9 mg g-1 . This study suggests that MXene may be promising in the treatment of hyperbilirubinemia.

Self-Assembly of Soft Cellulose Nanospheres into Colloidal Gel Layers with Enhanced Protein Adsorption Capability for Next-Generation Immunoassays.

Soft cationic core/shell cellulose nanospheres can deform and interpenetrate allowing their self-assembly into densely packed colloidal nanogel layers. Taking advantage of their water-swelling capacity and molecular accessibility, the nanogels are proposed as a new and promising type of coating material to immobilize bioactive molecules on thin films and paper. The specific and nonspecific interactions between the cellulosic nanogel and human immunoglobulin G as well as bovine serum albumin (BSA) are investigated. Confocal microscopy, electroacoustic microgravimetry, and surface plasmon resonance are used to access information about the adsorption behavior and viscoelastic properties of self-assembled nanogels. A significant BSA adsorption capacity on nanogel layers (17mg m-2 ) is measured, 300% higher compared to typical polymer coatings. This high protein affinity further confirms the promise of the introduced colloidal gel layer, in increasing sensitivity and advancing a new generation of substrates for a variety of applications, including immunoassays, as demonstrated in this work.

Effect of sintering temperature on sorption properties and compressive strength of calcium phosphate ceramic granules

In this study we determined sintering temperature effect on bovine serum albumin (BSA) adsorption and compressive strength of calcium phosphate ceramic granules. Hydroxyapatite (HAp) and biphasic calcium phosphate (BCP) with HAp and β-tricalcium phosphate ratio 50:50 granules were prepared by sintering at 1000, 1100, 1150 and 1200 °C. HAp granules showed higher compressive strength than BCP, at 1200 °C reaching 7.1 ± 0.2 MPa and 5.4 ± 0.4 MPa, respectively. For samples sintered at higher temperatures the adsorption capacity in mg/g and mg/ml (adsorbed BSA per bulk volume of granules) decreases whereas the capacity in mg/m2 (adsorbed BSA per one square meter of granules surface area) increases. BSA adsorption capacity in current research is compared with other results presented in literature, concluding that for samples with lower specific surface area the adsorption capacity in mg/m2 is increased.

Cellulose Nanofibrous Membranes Modified with Phenyl Glycidyl Ether for Efficient Adsorption of Bovine Serum Albumin

Hydrophobic interaction chromatography (HIC) as an indispensable method for protein purification has attracted considerable attentions of researchers as well as biopharmaceutical industries. However, the low binding capacity and slow adsorption rate of the currently available HIC media lead to a little supply and high price of the highly purified proteins. Herein, nanofibrous membranes with hydrophobic binding sites were developed for HIC by directly coupling phenyl glycidyl ether on the hydrolyzed cellulose acetate nanofiber membrane (cellulose-phenyl NFM). Scanning electron microscope (SEM), water contact angle (WCA), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) surface area analysis and capillary flow porometer (CFP) were applied to evaluate the physically and chemically structural transformation. The obtained cellulose-phenyl NFMs showed a proper hydrophilcity (WCA = 37°), a relatively high BET surface area (3.6 times the surface area of commercial fibrous membranes), and tortuous-channel structure with through-hole size in the range of 0.25–1.2 μm, which led to a little non-specificity adsorption, high bovine serum albumin adsorption capacity of 118 mg g−1, fast adsorption process within 12 h, good long-term stability and reusability. Moreover, compared with traditional modification methods which always include activation and graft two steps, direct coupling method is more efficient for HIC media fabrication. Therefore, cellulose-phenyl NFMs with outstanding protein adsorption performance could be a kind of promising candidate for HIC.

Synthesis of Magnetic Fe3O4 Nanorings for BSA Protein Adsorption

AbstractThe adsorption of bovine serum albumin (BSA) protein is important for protein research but remains a great challenge. Here, the hydrothermal method and calcination in a hydrogen-argon mixed atmosphere were used to obtain ordered mono-crystalline magnetic Fe3O4 nanorings with controllable size and uniform structure, which were applied to the adsorption of BSA protein. The results showed that the magnetic Fe3O4 nanorings prepared have the advantages of good crystallinity, controllable morphology, and excellent magnetic response. The Fe3O4 nanorings had an outer diameter of ~160–180 nm, inner diameter of ~80–110 nm, and height of 70 to ~110 nm. The amount of BSA adsorbed by magnetic Fe3O4 nanorings increased with increasing protein concentration; when the concentration of BSA was ~2.75 mg·mL-1 the adsorption amount approached saturation. When the pH value of the solution was ~5, the Fe3O4 nanorings absorption of BSA was greatest. With increasing adsorption time, the amount adsorbed increased gradually. Adsorption equilibrium was reached after 3 h. According to the formula, the saturated adsorption capacity of BSA per gram of magnetic Fe3O4 nanorings was 325.2 mg.Graphical Abstract

Adsorption of Serum Albumin onto Octacalcium Phosphate in Supersaturated Solutions Regarding Calcium Phosphate Phases.

Octacalcium phosphate (OCP) has been shown to enhance new bone formation, coupled with its own biodegradation, through osteoblasts and osteoclast-like cell activities concomitant with de novo hydroxyapatite (HA) formation and serum protein accumulation on its surface. However, the nature of the chemical environment surrounding OCP and how it affects its metabolism and regulates protein accumulation is unknown. The present study examined how the degree of supersaturation (DS) affects the bovine serum albumin (BSA) adsorption onto OCP in 150 mM Tris-HCl buffer at 37 °C and pH 7.4, by changing the Ca2+ ion concentration. The amount of BSA adsorbed onto OCP increased as the DS increased. In addition, the amount of newly formed calcium phosphate, which could be OCP, was increased, not only by increases in DS, but also at lower equilibrium concentrations of BSA. The increased adsorption capacity of BSA was likely related to the formation of calcium phosphate on the adsorbed OCP. Together the results suggested that the formation of new calcium phosphate crystals is dependent on both the DS value and the adsorbate protein concentration, which may control serum protein accumulation on the OCP surface in vivo.

Surface molecularly imprinted thermo-sensitive polymers based on light-weight hollow magnetic microspheres for specific recognition of BSA

Effective specific recognition of bovine serum albumin (BSA) was accomplished by the thermo-sensitive imprinted microspheres composed of N-isopropylacrylamide (NIPAM), methacrylic acid (MAA) and N,N-methylenebisacrylamide (MBA). These imprinted microspheres were prepared in the presence of hollow Fe3O4 microspheres as substrates via surface molecular imprinting technique (MIT) and grafting copolymerization method. In the imprinting system, hollow Fe3O4 microspheres possessed the distinctive properties of excellent water dispersibility, light weight and high specific surface area. These potential benefits not only reduced the agglomeration of imprinted microspheres, but also increased the effective imprinting area for BSA. And owing to the existence of poly-(N-isopropylacrylamide) (pNIPAM), the fabricated molecularly imprinted polymers (MIPs) were highly sensitive to ambient temperature and played a significant role in efficient recognition for BSA. When treated at 32 °C, the optimal adsorption capacity (Q) and imprinting factor (IF) for BSA were obtained, 430.67 mg/g and 2.01, respectively. Combining hollow Fe3O4 microspheres with thermo-sensitive polymers, the surface-imprinted materials for specific capture of target protein would show great promise for bioseparation and biosensors.

MWCNT interactions with protein: surface-induced changes in protein adsorption and the impact of protein corona on cellular uptake and cytotoxicity.

PurposeProtein adsorption onto nanoparticles in the form of protein corona, affects properties of nanomaterials and their behavior in the biological milieu. This study aims at exploring the effects of multiwalled carbon nanotubes (MWCNTs) surface chemistry on bovine serum albumin (BSA) and immunoglobulin G (IgG), including their adsorption behavior and spatial configurations, as well as the impact on cellular uptake, cytotoxicity, and cellular responses.MethodsThree types of MWCNTs (pristine MWCNTs, MWCNTs-COOH, and MWCNTs-PEG) were synthesized by classical chemical reduction. The size, morphology, hydrodynamic size, and zeta potential were characterized using transmission electron microscopy and dynamic light scattering. MWCNTs were exposed to BSA and IgG solutions, then the amount of MWCNT absorption was performed by bicinchoninic acid assay, and the effects were assessed by utilizing fluorescence spectroscopy, circular dichroism (CD) spectroscopy. Quantitative measurement of MWCNTs uptake with or without protein corona was performed as turbidity method. CCK assay and a microdilution method were performed to evaluate the effects of protein corona on cytotoxicity and pro-inflammatory cytokines release.ResultsThe BSA and IgG adsorption capacities of MWCNTs followed the order pristine MWCNTs>MWCNTs-COOH and MWCNTs-PEG. MWCNT binding can cause fluorescence quenching and conformational changes in BSA and IgG, indicating that both the physicochemical properties of MWCNTs and protein properties play critical roles in determining their adsorption behavior. Further study showed time-dependent increases in MWCNT cellular uptake and internalization. Hydrophobicity is the major factor increasing cellular uptake of pristine MWCNTs, but a protein corona enriched with dysoposnins is the main factor reducing uptake of MWCNT-COOH by RAW264.7 cells. The cytotoxicity and pro-inflammatory response related to physicochemical properties of MWCNTs, and frustrated phagocytosis is a key initiating event in the pro-inflammatory response of MWCNT-exposed macrophages.ConclusionThese findings shed light on how functionalized MWCNTs interact with protein coronas and provide useful insight into the dramatic effect of protein coronas on different functionalized MWCNTs. These events affect cellular uptake and cytotoxicity, which could inform how to enhance MWCNT biocompatibility and develop approaches for managing MWCNT hazards.