Adsorption Of Bovine Serum Albumin Research Articles

Kinetic Relationships of the Adsorption of Lysozyme and Bovine Serum Albumin onto Zeolites of BEA and MFI Structural Types

Kinetic Relationships of the Adsorption of Lysozyme and Bovine Serum Albumin onto Zeolites of BEA and MFI Structural Types

Impact of Lipid Composition on Vesicle Protein Adsorption: A BSA Case Study.

Investigating the interaction between liposomes and proteins is of paramount importance in the development of liposomal formulations with real potential for bench-to-bedside transfer. Upon entering the body, proteins are immediately adsorbed on the liposomal surface, changing the nanovehicles' biological identity, which has a significant impact on their biodistribution and pharmacokinetics and ultimately on their therapeutic effect. Albumin is the most abundant plasma protein and thus usually adsorbs immediately on the liposomal surface. We herein report a comprehensive investigation on the adsorption of model protein bovine serum albumin (BSA) onto liposomal vesicles containing the zwitterionic lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), in combination with either cholesterol (CHOL) or the cationic lipid 1,2-dioleoyl-3-trimethylammoniumpropane (DOTAP). While many studies regarding protein adsorption on the surface of liposomes with different compositions have been performed, to the best of our knowledge, the differential responses of CHOL and DOTAP upon albumin adsorption on vesicles have not yet been investigated. UV-vis spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a strong influence of the phospholipid membrane composition on protein adsorption. Hence, it was found that DOTAP-containing vesicles adsorb proteins more robustly but also aggregate in the presence of BSA, as confirmed by DLS and TEM. Separation of liposome-protein complexes from unadsorbed proteins performed by means of centrifugation and size exclusion chromatography (SEC) was also investigated. Our results show that neither method can be regarded as a golden experimental setup to study the protein corona of liposomes. Yet, SEC proved to be more successful in the separation of unbound proteins, although the amount of lipid loss upon liposome elution was higher than expected. In addition, coarse-grained molecular dynamics simulations were employed to ascertain key membrane parameters, such as the membrane thickness and area per lipid. Overall, this study highlights the importance of surface charge and membrane fluidity in influencing the extent of protein adsorption. We hope that our investigation will be a valuable contribution to better understanding protein-vesicle interactions for improved nanocarrier design.

Titania Nanoparticles Doped Electrospun Membranes

Electrospun membranes exhibit very promising properties, such as high surface area, high surface area-to-pore volume ratio, high pore interconnectivity, and uniform pore distribution. Nanoparticles are a promising alternative for improving the properties of the electrospun membranes. Titania nanoparticles, which are stable, resistant, and non-toxic, have various applications including water treatment, sensors, food additive and cosmetics. Due to the high hydrophilicity of titania nanoparticles, membrane fouling is reduced in titania nanoparticles doped membranes. Titania nanoparticle doped polyacrylonitrile (PAN) nanocomposite electrospun membranes were prepared by electrospinning method in this work. Compared to bare PAN electrospun membranes 0.05% titania nanoparticles doped electrospun membranes have thinner nanofibers, higher hydrophilicity and almost 2 times lower bovine serum albumin adsorption, which shows lower fouling tendency.

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.

BSA Adsorption on Titanium Dioxide Nanoparticle Surfaces for Controlling Their Cellular Uptake in Skin Cells.

Nanoparticles (NPs) are continuously being developed for many applications including imaging, biomedicine, and everyday products. It is difficult to avoid contact with NPs such as titanium dioxide (TiO2) NPs, which are widely used in sunscreens. However, the safety of TiO2 NPs for skin contact and inhalation remains controversial. If NPs cannot penetrate the skin, they will be unable to circulate in the bloodstream, accumulate in the body, or cause side effects, ensuring their safety. Therefore, this study aimed to modify TiO2 NP surfaces to inhibit their uptake in skin cells. Inspired by protein corona studies, bovine serum albumin (BSA) was chosen to functionalize TiO2 NP surfaces via physical adsorption. The maximum BSA adsorption occurred at pH 5.0. The physicochemical properties (size, ζ-potential, morphology, ultraviolet (UV) absorption efficiency, and sun protection factor (SPF)) of TiO2-BSA NPs were comparable to those of TiO2 NPs, indicating that these properties did not affect cellular uptake. In the safety evaluation, TiO2 NPs and TiO2-BSA NPs exhibited high biocompatibility with skin cells and no phototoxicity after UVA and UVB irradiation. In the efficacy evaluation, both NPs possessed the same photoprotection abilities, reducing membrane damage and DNA breakage after UVA irradiation. Compared with TiO2 NPs, TiO2-BSA NPs showed substantially reduced skin penetration in Franz diffusion cells (91%) and human immortalized keratinocyte (HaCaT) cells (89%). A qualitative cellular uptake study using transmission electron microscopy and confocal laser scanning microscopy confirmed that TiO2 NPs were more abundant than TiO2-BSA NPs inside the HaCaT cells. These findings indicate that TiO2 surface functionalization with BSA inhibits cellular uptake in skin cells while maintaining safety and UV protection efficacy, which might be extended to other NP-based sunscreens.

Real-time tracking of the adsorption of bovine serum albumin on lipid layer and its effect on lipolysis by optical interferometry

The model proteins bovine serum albumin (BSA) and lipid layer were used to study the effect of proteins on lipolysis. A lipid layer with an interference effect was constructed by loading the triolein into the silica colloidal crystal (SCC) film. The ordered porous layer interferometry (OPLI) system was used to track the changes in lipid layer mass caused by lipase hydrolysis to achieve real-time lipolysis detection. The real-time tracking of the adsorption of BSA on the lipid layer by converting the migration of interference fringes caused by the change of the lipid layer into the optical thickness change (ΔOT). The effect of BSA on the early and late stages of lipolysis was studied, and lipases containing 5 mg/mL BSA degraded the lipid layer 3.4 times faster than lipases containing 0.1 mg/mL BSA in the later stages. This study deepens the understanding of protein-lipid interactions in complex digestive environments.

Interfacial modification of hydrogel composite membranes for protein adsorption with cavitands as nano molecular containers

Protein adsorption is of great significance for bioengineering, biomedicine, drug release, etc. Herein, poly-N-isopropylacrylamide (PNIPAm) and polyethylene glycol diacrylate (PEGDA) based hydrogel materials were used to introduce self-synthesized cavitands with pore cage structures and hydrophobic characteristics to construct high-efficiency hydrogel composite membrane (HCM) for the adsorption of bovine serum albumin (BSA). The hydrophobic cavitand cage can improve the interfacial polymerization process by impacting the monomer diffusion and then modifying the interface properties of the hydrogel molecular network, which is validated by the molecular dynamic simulation. The adsorption mechanism can be interpreted as the reorganization of the polymer pores using the cavitands, and hence the surface charge and hydrophobic property consequently changed, which is consistent with the measurement results as well as validated by the molecular dynamic simulation. Thus, the fabricated HCM exhibits good structural stability, thermal stability, and robust BSA adsorption performance. The results indicated that the developed HCM materials can be promising candidates for effective protein separation.

In situ Fourier transform infrared-attenuated total reflection spectroscopy and modeling investigation of protein adsorption: Case of expanded bovine serum albumin on titanium dioxide anatase.

The purpose of this experimental and modeling research is to study the pH effect and to determine the surface coverage plus the adsorption constant (Ka) of bovine serum albumin (BSA) protein adsorbed on TiO2 anatase surface, respectively. In situ Fourier transform infrared-attenuated total reflection spectroscopy in a flow-through cell was used to study the BSA adsorption on porous TiO2 anatase films. The experiments were performed in water solution, under different pH values, at a concentration of 10-6 mol/l. Theoretically, we extended the two-state model, based on a system of coupled differential equations, by adding a desorption parameter Kd2, for unfolded state. The model was solved taking into account the adsorption (Ka), desorption (Kd1,2), transformation (Kf) coefficients, and the initial solution protein concentration (C0). The findings clearly illustrated that the solution pH drastically changed the behavior of BSA adsorption, whereas the mathematical analytical solutions allowed us to determine the native state (θ1), the unfolded state (θ2), and the full one (θ) surface coverages. Finally, a good application of the approximated model on the experimental work, expanded BSA adsorbed on TiO2 anatase at pH = 1.7, indicated a value of Ka = (408.36 ± 0.996) × 102 mol-1 l min-1.

Preparation of aminated poly (L‐lactic acid) film coated with multilayers of mussel‐inspired heparin‐like carboxymethylcellulose sodium and chitosan for anticoagulant materials

AbstractIn this study, dopamine hydrochloride was grafted onto the sulfated carboxymethylcellulose sodium with different sulfated degree (DA‐g‐SCMCS) as heparin‐like polysaccharides. By studying the preliminary structure and coagulation time of DA‐g‐SCMCS, the DA‐g‐SCMC2 possessing good anticoagulant properties were selected to be assembled layer by layer on the surface of aminated poly (L‐lactic acid) (APLLA) film with chitosan (CS). The characterization properties including morphologies and wettability of DA‐g‐SCMC2/CS multilayers modified APLLA films were studied by scanning electron microscope and water contact angle instrument. Anticoagulation tests revealed that the (DA‐g‐SCMC2/CS)15 multilayers modified APLLA film experienced a decrease of 37.5% and 73.68% in the adsorption of bovine serum albumin (BSA) and fibrinogen (FBG), respectively. And the platelet adhesion ability was reduced by 92.42% compared with the APLLA film. The degree of platelet activation (PF4 and TAT) and hemolysis rates of modified APLLA films also decreased significantly. Besides, the modified APLLA films promoted the growth of L929 cells and exhibited remarkable anti‐inflammatory and antibacterial abilities. To summarize, the APLLA films modified with heparin‐like multifunctional DA‐g‐SCMC2/CS multilayers exhibit outstanding biocompatibility, cytocompatibility, anti‐inflammatory, and antibacterial characteristics, showcasing their potential as anticoagulation materials.

Nanofiltration membrane fabricated by combination of phase inversion and stepwise interfacial complexation

Novel thin-film-composite (TFC) nanofiltration (NF) membranes with polysulfone (PSF)/sulfonated polytrifluorostyrene (SPTFS) substrate and polyethyleneimine (PEI)/SPTFS selective layer were fabricated via the combination of phase inversion and stepwise interfacial complexation. As the increase in SPTFS additive during phase inversion, PSF/SPTFS substrates exhibited macrovoids cross-sectional structures, smaller water contact angle, lower surface zeta potential, and excellent water flux. The PEI/SPTFS selective layer was constructed through stepwise interfacial complexation. Attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results verified the successful complexation of polyelectrolytes on PSF/SPTFS substrate. The water flux and selectivity experiments revealed that the TFC membrane with a single PEI/SPTFS bilayer (TFC-1) presented a desired pure water flux of 28.0 (L m−2 h−1 bar−1) and excellent dye rejections of MB, CR, AR66 above 98 %. Moreover, TFC-1 membrane demonstrated a ∼11-fold lower adsorption of bovine serum albumin (BSA, 5.8 µg cm−2) compared to the pristine PSF membrane, indicating a great static anti-pollution performance. This study provides a facile strategy to prepare fluoropolymer-modified NF membranes with high water flux, excellent dye rejection and low non-specific adsorption.

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.

Flexible Poly(vinyl chloride) with Durable Antibiofouling Property via Blending Star-Shaped Amphiphilic Poly(ε-caprolactone)-block-poly(methacryloxyethyl sulfobetaine).

Flexible poly(vinyl chloride) (PVC) plastics have been widely used in medical devices, but the preparation of antibiofouling flexible PVC materials that can maintain their antibiofouling performance when suffering deformation is still a challenge. In this work, we synthesized a series of amphiphilic star-shaped three-arm block copolymers SPCL-b-PSB, consisting of hydrophobic inner blocks poly(ε-caprolactone) (PCL) and hydrophilic outer blocks poly(methacryloxyethyl sulfobetaine) (PSB). Then, flexible PVC films were prepared by blending SPCL-b-PSB with PVC and plasticizer. Benefiting from the specific star-shaped topological structure of SPCL-b-PSB, hydrophilic PSB blocks of the copolymer could efficiently migrate to the surface of the film via annealing treatment, which give the film surface excellent hydrophilicity, while the latch-like entanglements between hydrophobic PCL blocks and PVC give the hydrophilic surface excellent stability. Antibiofouling properties of the blended films were investigated. The optimized blended film could reduce ∼94% of bovine serum albumin adsorption, ∼ 87% of lysozyme adsorption, and ∼89% of platelet adhesion and resist bacterial adhesion effectively. What is more, the blended films could maintain their antibiofouling performance when suffering stretching, rubbing, or bending. More than 86% of bovine serum albumin adsorption could be reduced, even when the film was stretched by 50%. This work provides a new strategy for the preparation of durable antibiofouling flexible plastics.

Exfoliated clay-polymer nanocomposite as a promising delivery system for bovine serum albumin

ABSTRACT The pH-sensitive exfoliated clay-alginate composite was investigated for the controlled oral delivery of bovine serum albumin (BSA). The X-ray diffraction analysis and transmission electron microscopy analysis revealed the exfoliated structure of clay in the composite. The degree of exfoliation was increased with sonication and it was optimised that the maximum exfoliation of clay in the aqueous medium occurred for 150 min of sonication. The maximum adsorption of BSA in the clay-alginate was detected at a pH of 4.5. The in-vitro release study of BSA from the exfoliated clay and the clay-alginate composite was analysed at simulated gastric and simulated intestinal pH conditions which suggested that the adsorption and release of BSA could be controlled simply by adjusting the solution pH condition. In the in-vitro release study, it was noted that there was no release of BSA from the clay-alginate composite up to 30 min in gastric pH conditions. But, there was a slow release rate of BSA within 10 h from the clay-alginate composite in the intestinal pH condition. The release profile from the clay–alginate composite was more fitted to the Peppas kinetic model.

Composition-Dependent Protein-Material Interaction of Poly(Methyl Methacrylate-co-styrene) Nanoparticle Series.

Polymer nanoparticles continue to be of high interest in life science applications. Still, adsorption processes occurring in protein-containing media and their implications for biological responses are not generally predictable. Here, the effect of nanoparticle composition on the adsorption of bovine serum albumin (BSA), fibronectin (FN) and immunoglobulin G (IgG) as structurally and functionally different model proteins was explored by systematically altering the composition of poly(methyl methacrylate-co-styrene) nanoparticles with sizes in a range of about 550 nm. As determined by protein depletion from the suspension medium via a colorimetric assay, BSA and IgG adsorbed at similar quantities, while FN reached larger masses of adsorbed protein (up to 0.4 ± 0.06 µg·cm-2 BSA, 0.42 ± 0.09 µg·cm-2 IgG, 0.72 ± 0.04 µg·cm-2 FN). A higher content of styrene as the more hydrophobic polymer component enhanced protein binding, which suggests a contribution of hydrophobic interactions despite the particles exhibiting strongly negatively charged surfaces with zeta potentials of -44 to -52 mV. The quantities of adsorbed proteins were estimated to correspond to a confluent surface coverage. Overall, this study illustrated how protein binding can be controlled by systematically varying the nanoparticle bulk composition and may serve as a basis for establishing interfaces with a targeted level of protein retention and/or presentation.

Stereoselective Voltammetric Biosensor for Myo-Inositol and D-Chiro-Inositol Recognition.

This paper describes the development of a simple voltammetric biosensor for the stereoselective discrimination of myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) by means of bovine serum albumin (BSA) adsorption onto a multi-walled carbon nanotube (MWCNT) graphite screen-printed electrode (MWCNT-GSPE), previously functionalized by the electropolymerization of methylene blue (MB). After a morphological characterization, the enantioselective biosensor platform was electrochemically characterized after each modification step by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The results show that the binding affinity between myo-Ins and BSA was higher than that between D-chiro-Ins and BSA, confirming the different interactions exhibited by the novel BSA/MB/MWCNT/GSPE platform towards the two diastereoisomers. The biosensor showed a linear response towards both stereoisomers in the range of 2-100 μM, with LODs of 0.5 and 1 μM for myo-Ins and D-chiro-Ins, respectively. Moreover, a stereoselectivity coefficient α of 1.6 was found, with association constants of 0.90 and 0.79, for the two stereoisomers, respectively. Lastly, the proposed biosensor allowed for the determination of the stereoisomeric composition of myo-/D-chiro-Ins mixtures in commercial pharmaceutical preparations, and thus, it is expected to be successfully applied in the chiral analysis of pharmaceuticals and illicit drugs of forensic interest.

Synthesizing a multifunctional polymer to construct the catalytically NO-generating coating for improving corrosion resistance and biocompatibility of the magnesium alloy stent materials

Owing to its excellent mechanical properties and biodegradability, magnesium-based alloys have become the research focus of biodegradable cardiovascular materials. However, the in vivo rapid degradation and poor surface endothelial regeneration and repair ability still restrict their clinical applications in the field of vascular stent materials. Nitric oxide (NO), as an endogenous gas signaling molecule, has multiple effects such as anticoagulation, promoting endothelialization, and anti-restenosis, showing a great potential for improving the performances of the cardiovascular materials and devices. In the present study, based on six-arm polyethylene glycol (PEG), a novel anticoagulant polymer (PEG-Hep-SeCA) with the catalytic release of NO was synthesized by successively introducing heparin and selenocystamine, followed by the immobilization of the as-synthesized polymer on the Zn2+-loaded polydopamine coating modified magnesium alloy surface to enhance the anti-corrosion and biocompatibility. The results demonstrated that the PEG-Hep-SeCA polymer coating was uniform and dense, which could not only obviously enhance the anticorrosion and the hydrophilicity of the magnesium alloy, but also selectively promote the bovine serum albumin (BSA) adsorption, thereby significantly improving the endothelial cells (ECs) growth and hemocompatibility. Additionally, the as-prepared polymer coating could effectively catalyze the release of NO from endogenous NO donors, which can further ameliorate the hemocompatibility and ECs growth, as well as enhance the expression of vascular endothelial cell growth factor (VEGF) and NO of the ECs. Therefore, this study opens a new way to construct the multifunctional coating with the ability of catalytic releasing NO on the surfaces of the magnesium-based alloys to simultaneously reduce the corrosion speed, improve the hemocompatibility, and accelerate the reendothelialization.

Utilization of an aqueous two-phase emulsification to prepare bimodal porous cellulose monolith for efficient adsorption of bovine serum albumin

Cellulose monolith has garnered significant interest in the field of biochromatography, which lies in its interconnected porous structure, large surface area and biocompatibility. In this context, we propose a novel approach for preparing cellulose monoliths using an aqueous two-phase system devoid of any organic solvents and surfactants. In this strategy, emulsifying cellulose solution into PEG 20,000 solution gives bicontinuous aqueous phases and further porous cellulose monolith after regeneration of dissolved cellulose. And the macroporous channels are derived from the removal of the PEG 20,000 aqueous phase while the micropores are from the phase separation of the cellulose phase. Physical characterizations reveal the obtained cellulose monolith exhibits exceptional column permeability of 1.36 × 10−11 m2 and a substantial surface area of 39.34 m2/g. Furthermore, cellulose monolith is functionalized with diethyl ethylamine hydrochloride (DEAE-HCl) to evaluate its potential as an anion adsorbent. Experimental results reveal that the DEAE-modified cellulose monolith possesses of adsorptive capacity of 316.58 mg/g of bovine serum albumin, along with fast adsorption kinetic. This study introduces an innovative strategy for fabricating porous cellulose monoliths tailored for biochromatography applications.

Antifouling Surfaces Based on Polyzwitterion Loop Brushes.

Antifouling surfaces have attracted increasing interest in recent years due to their potential application in various fields. In this work, we report a loop polyzwitterionic coating that exhibits excellent resistance to protein adsorption. Triblock and diblock copolymers of 2-[(2-hydroxyethyl)disulfanyl]ethyl methacrylate) (HSEMA) and 2-(dimethylamino)ethyl methacrylate) (DMAEMA) were synthesized by atom-transferred radical polymerization, followed by betainization of the DMAEMA block with 1,3-propane sultone and reduction of the disulfide bond in HSEMA to yield a triblock copolymer comprising a zwitterionic poly(sulfobetaine methacrylate) (PSBMA) midblock and poly(2-sulfanylethyl methacrylate) (PSEMA) terminal blocks as well as its diblock analogue that was of the same composition as the former and half the chain length. Both copolymers adsorbed to the gold substrate via the thiol groups in the terminal PSEMA block(s), creating loop and linear PSBMA brush coatings of comparable thickness, as revealed by X-ray photoelectron spectroscopy and ellipsometry. Adsorption of bovine serum albumin and fibrinogen as model proteins from solution to these surfaces was investigated by a quartz crystal microbalance with dissipation and confocal laser scanning microscopy (CLSM), and platelet and bacterial adhesions were assessed by scanning electron microscopy and CLSM. The results demonstrate that both linear and loop polyzwitterion brushes are excellent in resisting the adsorption of the foulants, and the loop brushes are superior to the linear analogues.

Synthesis of a porous hollow magnetic molecularly imprinted microsphere by O/W/O composite emulsion polymerization for specifically recognizing bovine serum albumin

Molecular imprinting technology is highly successful for low-molecular-weight molecules, but is still confronted with many challenges for proteins. This study introduces a strategy to synthesize hollow magnetic molecularly imprinted microspheres (HMMIMs) under Fe3O4 magnetic nanoparticles matrix, by oil-in-water-in-oil composite emulsion polymerization with alkylphenol ethoxylates and Span-80 as emulsifiers. The synthesis conditions after optimization were 1.0 mmol thermo-sensitive functional monomer N-isopropylacrylamide, 1.0 mmol cross-linker N, N-methylene bisacrylamide, 2.0 wt% vinyl-modified silk fibroin, and 50 mg Fe3O4@COOH nanoparticles. The morphology structure and the forming process of the acquired HMMIMs were well characterized by POM, SEM, TEM and FT-IR. The HMMIMs were synthesized successfully with a porous structure and large specific surface area. The particle size of the obtained HMMIMs was at 10–20 µm. The obtained microspheres were superparamagnetic and thermo-responsive. The HMMIM adsorption capacity at 25 °C toward bovine serum albumin (BSA) was 89.9 mg/g and the BSA separation factor in BSA/BHb mixtures was 2.12. A good separation efficacy toward BSA was also observed in bovine whole blood. The prepared HMMIM possessed heterogeneous active sites, the BSA adsorption process on HMMIM was chemisorption controlled.

Investigation of differences in the protein transport capability of homochiral nanochannels

Chiral recognition plays a crucial role in the normal functioning of biological systems. The recognition of proteins in chiral environments underpins many fundamental life processes. Taking advantage of the distinct interactions between different proteins and chiral environments, this study presents the design of homochiral metal–organic framework (MOF)/nanochannels based membrane separator, enabling highly selective and high-throughput protein separation. The chiral separation membrane was fabricated by employing TiO2 nanochannel membrane (TM) as the supporting membrane and Ti ion source. Using terephthalic acid (BDC) and d/l-phenylalanine (DP/LP) as ligands, a layered TiMOF (MIL-125(Ti) used in this study) incorporating chiral selector molecules (named as DP/M and LP/M) were synthesized in situ within the TiO2 nanochannels. The bovine serum albumin (BSA) adsorption capacity of DP/M decorated TM was demonstrated to be 2.8 times higher than that of LP/M decorated TM, and was found to be related to the content of the chiral selector DP in the separation membrane. Furthermore, different recognition abilities by the chiral channels were observed for proteins with different isoelectric points. Based on a comprehensive exploration of the variations in the interaction forces between protein and chiral selector molecules, a nanoscale chromatography column-like separation model was proposed. The chiral separation membranes designed in this study provide a new platform for understanding the interactions between chiral compounds and proteins, and open up new avenues for fabricating chiral bio-interface materials, elucidating the role of chiral recognition in biological systems, and developing novel biomaterials and devices.