Adsorption Of Human Serum Albumin Research Articles

Ionic strength effect in HSA adsorption on mica determined by streaming potential measurements

Adsorption and desorption of human serum albumin (HSA) from aqueous solutions on mica were studied using AFM and in situ streaming potential measurements. A quantitative interpretation of these experiments was achieved in terms of the theoretical model postulating a 3D adsorption of HSA molecules as discrete particles. These measurements, performed for various ionic strength, allowed one to determine the coverage of HSA as a function of the zeta potential of mica. This allowed one to determine the amount of irreversibly bound HSA as a function of the ionic strength. It was found that the coverage of irreversibly adsorbed HSA increased from 0.52mgm−2 for I=1.3×10−3M to 1.6mgm−2 for I=0.15M (pH=3.5). The significant role of ionic strength was attributed to the lateral electrostatic repulsion among adsorbed HSA molecules, positively charged at this pH value. This was quantitatively interpreted in terms of the effective hard particle concept previously used for colloid particles. The experimental results confirmed that monolayers of irreversibly bound HSA of a well-controlled coverage can be produced by adjusting the ionic strength of the suspension.

IgG purification by negative chromatography in amine-based ligands: A comparison of l-lysine and poly-l-lysine

Agarose gels with immobilized amine-based ligands l-lysine (Lys) and poly-l-lysine (PLL) exhibited the ability to adsorb human serum proteins and to separate immunoglobulin G (IgG) in nonretained chromatographic fractions (negative chromatography). The effect of the buffer system and pH on IgG purification on Lys-agarose and PLL-agarose showed that PLL was the most selective ligand. PLL-agarose was able to purify IgG from human serum solution diluted in Bis–Tris buffer at pH 6.0 with 79% yield and 88.7% purity (based on total protein concentration and nephelometric analysis of albumin, transferrin, and immunoglobulins A, G, and M). Human serum albumin (HSA) and IgG adsorption data showed that the first followed the Langmuir model whereas the second followed the Langmuir–Freundlich model, due to the presence of a positive cooperativity effect (n=1.60), with the maximum adsorption capacities of 76.4mgmL−1 for HSA and 23.6mgmL−1 for IgG. The ΔGmax values obtained by non-linear regression of HSA and IgG adsorption data of Temkin model were similar (−7.0kcalmol−1), indicating that the process is spontaneous in nature. The joint analysis of these data shows that PLL-agarose can be considered an alternative adsorbent for the isolation of IgG from human serum with the potential to be integrated to a purification process on a large scale.

Investigation of protein adsorption performance of Ni2+‐attached diatomite particles embedded in composite monolithic cryogels

As a low-cost natural adsorbent, diatomite (DA) (2 μm) has several advantages including high surface area, chemical reactivity, hydrophilicity and lack of toxicity. In this study, the protein adsorption performance of supermacroporous composite cryogels embedded with Ni(2+)-attached DA particles (Ni(2+)-ADAPs) was investigated. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic composite cryogel column embedded with Ni(2+)-ADAPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N'-methylene-bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for affinity purification of human serum albumin (HSA) both from aqueous solutions and human serum. The chemical composition and surface area of DA was determined by XRF and BET method, respectively. The characterization of composite cryogel was investigated by SEM. The effect of pH, and embedded Ni(2+)-ADAPs amount, initial HSA concentration, temperature and flow rate on adsorption were studied. The maximum amount of HSA adsorption from aqueous solution at pH 8.0 phosphate buffer was very high (485.15 mg/g DA). It was observed that HSA could be repeatedly adsorbed and desorbed to the embedded Ni(2+)-ADAPs in poly(2-hydroxyethyl methacrylate) composite cryogel without significant loss of adsorption capacity. The efficiency of albumin adsorption from human serum before and after albumin adsorption was also investigated with SDS-PAGE analyses.

MAGNETIC DYE-AFFINITY BEADS FOR HUMAN SERUM ALBUMIN PURIFICATION

Cibacron Blue F3GA was covalently attached onto magnetic poly(vinyl alcohol) (mPVAL) beads (100–150 μm in diameter) for human serum albumin (HSA) adsorption from human plasma. Despite low nonspecific adsorption of HSA on mPVAL beads, Cibacron Blue F3GA attachment significantly increased the HSA adsorption. The maximum HSA adsorption was observed at pH 5.0. Higher HSA adsorption was observed from human plasma. Desorption of HSA from mPVAL beads was achieved by medium containing 1.0 M KSCN at pH 8.0. To test the efficiency of albumin adsorption from human serum, before and after albumin adsorption was demonstrated with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analyses. HSA molecules could be reversibly adsorbed and desorbed 10 times with the magnetic beads without noticeable loss in their HSA adsorption capacity.

Deposition of silicon doped and pure hydrogenated amorphous carbon coatings on quartz crystal microbalance sensors for protein adsorption studies

In this study hydrogenated amorphous carbon films (a-C:H) and silicon doped hydrogenated amorphous carbon films (a-C:H:Si) with different hydrogen and silicon contents were deposited onto sensors of a quartz crystal microbalance with dissipation detection (QCM-D). The resulting films were investigated with regard to their structural and elemental compositions using Raman spectroscopy, elastic recoil detection analysis and Rutherford backscattering spectroscopy. Furthermore the surface free energy (SFE) of the films was determined using contact angle measurements. The polar part of SFE of the a-C:H:Si films was found to be adjustable by the silicon content in these films and increased by increasing amounts of silicon. Carbon films with a broad range of chemical composition showed similar structure and properties when deposited on QCM-D sensors as compared with the deposition on silicon wafers. Subsequently, the amorphous carbon coated QCM-D sensors were used to study the adsorption of human serum albumin. These QCM-D results were related to the surface properties of the films.

Adsorption and photocatalytic degradation of human serum albumin on TiO 2 and Ag–TiO 2 films

Titanium dioxide is a useful material in the biomedical field as it has excellent biocompatibility based on its non-toxicity and non-inflammatory properties. Furthermore, TiO 2 can be excited by UV light to create charge carriers giving rise to photocatalytic redox reactions at the surface and photo-induced super-hydrophilicity. These properties might be exploited for surface decontamination of medical devices and implants. With this in mind, titanium dioxide TiO 2 films were prepared on stainless steel substrates using magnetron sputtering. Silver loaded (Ag–TiO 2) films were prepared by the photocatalytic reduction of Ag + from solution. The adsorption of human serum albumin (HSA) was studied. Surface analysis methods used included X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and atomic force microscopy (AFM). The TiO 2 films were predominantly anatase crystal phase and the photoreduced Ag was present at greater than 90% of the silver content as Ag 0 on the surface. Ag loading of the TiO 2 markedly enhanced the Raman signal (ca. 15-fold), but caused significant changes to the spectrum indicating non-specific binding of protein side chain residues to the Ag. The amide I and III modes remained well-resolved and were used to estimate the conformational change induced by the Ag. Raman analysis showed an increase in the intensity of the band at ∼1665 cm −1 assigned to the disordered conformation, suggesting that the adsorption to the Ag sites induces conformational changes in the protein. UVB irradiation of the protein contaminated surfaces caused further changes in the protein conformation, consistent with denaturation and enhanced binding and oxidation, thought to be induced through a photocatalytic mechanism.

Interaction of curcumin nanoformulations with human plasma proteins and erythrocytes

BackgroundRecent studies report curcumin nanoformulation(s) based on polylactic-co-glycolic acid (PLGA), β-cyclodextrin, cellulose, nanogel, and dendrimers to have anticancer potential. However, no comparative data are currently available for the interaction of curcumin nanoformulations with blood proteins and erythrocytes. The objective of this study was to examine the interaction of curcumin nanoformulations with cancer cells, serum proteins, and human red blood cells, and to assess their potential application for in vivo preclinical and clinical studies.MethodsThe cellular uptake of curcumin nanoformulations was assessed by measuring curcumin levels in cancer cells using ultraviolet-visible spectrophotometry. Protein interaction studies were conducted using particle size analysis, zeta potential, and Western blot techniques. Curcumin nanoformulations were incubated with human red blood cells to evaluate their acute toxicity and hemocompatibility.ResultsCellular uptake of curcumin nanoformulations by cancer cells demonstrated preferential uptake versus free curcumin. Particle sizes and zeta potentials of curucumin nanoformulations were varied after human serum albumin adsorption. A remarkable capacity of the dendrimer curcumin nanoformulation to bind to plasma protein was observed, while the other formulations showed minimal binding capacity. Dendrimer curcumin nanoformulations also showed higher toxicity to red blood cells compared with the other curcumin nanoformulations.ConclusionPLGA and nanogel curcumin nanoformulations appear to be very compatible with erythrocytes and have low serum protein binding characteristics, which suggests that they may be suitable for application in the treatment of malignancy. These findings advance our understanding of the characteristics of curcumin nanoformulations, a necessary component in harnessing and implementing improved in vivo effects of curcumin.

Fibronectin Conformation Switch Induced by Coadsorption with Human Serum Albumin

The dynamic adsorption of human serum albumin (HSA) and plasma fibronectin (Fn) onto hydrophobic poly(hydroxymethylsiloxane) (PHMS) and the structures of adsorbed protein layers from single and binary protein solutions were studied. Spectroscopic ellipsometry (SE) and quartz crystal microbalance with dissipation monitoring (QCM-D) together with atomic force microscopy (AFM) were used to measure the effective mass, thickness, viscoelastic properties, and morphology of the adsorbed protein films. Adsorbed HSA formed a rigid, tightly bound monolayer of deformed protein, and Fn adsorption yielded a thick, very viscoelastic layer that was firmly bound to the substrate. The mixed protein layers obtained from the coadsorption of binary equimolecular HSA-Fn solutions were found to be almost exclusively dominated by Fn molecules. Further sequential adsorption experiments showed little evidence of HSA adsorbed onto the predeposited Fn layer (denoted as Fn ≫ HSA), and Fn was not adsorbed onto predeposited HSA (HSA ≫ Fn). The conformational arrangement of the adsorbed Fn was analyzed in terms of the relative availability of two Fn domains. In particular, (4)F(1)·(5)F(1) binding domains in the Hep I fragment, close to the amino terminal of Fn, were targeted using a polyclonal antifibronectin antibody (anti-Fn), and the RGD sequence in the 10th segment, in the central region of the molecule, was tested by cell culture experiments. The results suggested that coadsorption with HSA induced the Fn switch from an open conformation, with the amino terminal subunit oriented toward the solution, to a close conformation, with the Fn central region oriented toward the solution.

A novel adsorbent for protein chromatography: Supermacroporous monolithic cryogel embedded with Cu2+-attached sporopollenin particles

The aim of this study is to prepare supermacroporous cryogels embedded with Cu2+-attached sporopollenin particles (Cu2+-ASP) having large surface area for high protein adsorption capacity. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic cryogel column embedded with Cu2+-ASP was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N′-methylene-bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for affinity purification of human serum albumin (HSA). Firstly, Cu2+ ions were attached to sporopollenin particles (SP), then the supermacroporous PHEMA cryogel with embedded Cu2+-ASP was produced by free radical polymerization using N,N,N′,N′-tetramethylene diamine (TEMED) and ammonium persulfate (APS) as initiator/activator pair in an ice bath. Embedded particles (10mg) in PHEMA-based cryogel column were used in the adsorption/desorption of HSA from aqueous solutions. Optimum conditions of adsorption experiments were performed at pH 8.0 phosphate buffer, with flow rate of 0.5mL/min, and at 5°C. The maximum amount of HSA adsorption from aqueous solution was very high (677.4mg/g SP) with initial concentration 6mg/mL. It was observed that HSA could be repeatedly adsorbed and desorbed to the embedded Cu2+-ASP in PHEMA cryogel without significant loss of adsorption capacity.

Adsorption of PEO–PPO–PEO triblock copolymers on a gold surface

Water-soluble triblock copolymers of Poly(ethylene oxide) and Poly(propylene oxide) (PEO n –PPO m –PEO n ) are nonionic amphiphilic macromolecules, commercially available under the names of Pluronics and Poloxamers. Recently interest has been focused on studying their roles in reducing nonspecific protein adsorption and cell adhesion on biomaterial/biosensor surfaces. Although the ability of the adsorbed PEO–PPO–PEO triblock copolymer to reduce protein adsorption has been observed frequently, its detailed mechanism of functioning is yet to be clarified. In order to delineate this detailed mechanism, one first needs to know the adsorption behavior of Pluronics on various substrates. Although gold is a commonly used substrate for the probes of various biosensors, there is no direct data reporting the adsorption behavior of Pluronics on it. In this study, we use surface plasma resonance (SPR) technique and Ellipsometry to detect the adsorption isotherms of various Pluronics on a gold surface. The adsorption isotherm of Pluronics of P103, P104 and F108 all exhibit two plateaus that corresponding to the desorption of the EO and the micellization in bulk solution. At bulk concentration of 1 × 10 −2 mg/ml, the total adsorbed amount of the copolymer increases with the increase of the molar mass of the polymer and with the decrease of the EO/PO ratio that suggests the strong influence of the hydrophobic PPO on the adsorbed amount of the polymer. At the CMC, the plateau value of adsorbed amount of Pluronics on Au is independent of molar mass and EO/PO ratio of copolymer. Protein adsorption on gold surfaces modified with various Pluronics shows good correlation between the amounts of protein adsorbed and the value of the reduced surface coverage, σ* of the Pluronic adlayer. In general, by increasing σ*, the nonspecific adsorption of human serum albumin can be reduced.

Inhibition of protein adsorption and cell adhesion on PNIPAAm-grafted polyurethane surface: Effect of graft molecular weight

In this work, the effect of molecular weight (MW) of surface grafted poly(N-isopropylacrylamide) (PNIPAAm) on protein adsorption and cell adhesion was investigated systematically. PNIPAAm-grafted polyurethane (PU) surfaces of varying graft MW were prepared via conventional radical polymerization. The MW was controlled by adjusting the monomer concentration. Fibrinogen (Fg) and human serum albumin (HSA) were selected as model proteins and their adsorption from phosphate-buffered saline (PBS, pH 7.4) and blood plasma at 37°C was measured using a radiolabeling method and immunoblot analysis respectively. It was found that in both media, as the MW increased, the adsorption of these two proteins decreased gradually reaching a plateau value at MW above 7.9×10(4). Compared to the unmodified PU, the surface grafted with PNIPAAm of MW 14.6×10(4) reduced the adsorption of Fg and HSA in PBS by 91% and 86%, respectively. Moreover, the surfaces with higher MW PNIPAAm showed minimal adhesion of L929 cells presumably due to the absence of cell-adhesive proteins on the surfaces.

Thermally-modulated on/off-adsorption materials for pharmaceutical protein purification

For the development of temperature-responsive adsorption materials for pharmaceutical protein purification, poly( N-isopropylacrylamide-co- N,N-dimethylaminopropylacrylamide-co- N-tert-butylacrylamide) (P(IPAAm- co-DMAPAAm- co-tBAAm) brush grafted silica beads were prepared through a surface-initiated atom transfer radical polymerization (ATRP). The prepared silica beads as a chromatographic stationary phase were evaluated by observing their thermo-responsive elution profiles of plasma proteins including human serum albumin (HSA) and γ-globulin. Chromatograms of two proteins indicated that negatively-charged HSA was adsorbed on the cationic copolymer brush modified silica beads at higher temperatures with low concentration of phosphate buffer (PB) (pH 7.0) as a mobile phase. The HSA adsorption was attributed to (1) an enhanced electrostatic interaction with the cationic copolymer brush at low concentration of PB and (2) an increased hydrophobic interaction from the dehydrated copolymer at high temperature. Step-temperature gradient enabled HSA and γ-globulin to be separated by the modulation of HSA adsorption/desorption onto the copolymer brush grafted silica beads. These results suggested that the prepared copolymer brush grafted silica beads adsorbed negatively-charged proteins both through electrostatic and hydrophobic interactions by the modulation of column temperature and gave attractive adsorption materials for protein purification process.

An X-ray Spectromicroscopy Study of Protein Adsorption to Polystyrene−Poly(ethylene oxide) Blends

Synchrotron-based X-ray photoemission electron microscopy (X-PEEM) and atomic force microscopy (AFM) were used to characterize the composition and surface morphology of thin films of a polystyrene-poly(ethylene oxide) blend (PS-PEO), spun cast from dichloromethane at various mass ratios and polymer concentrations. X-PEEM reveals incomplete segregation with ∼30% of PS in the PEO region and vice versa. Protein (human serum albumin) adsorption studies show that this partial phase separation leads to greater protein repellency in the PS region, whereas more protein is detected in the PEO region compared to control samples.

Effect of immobilization of polysaccharides on the biocompatibility of poly(butyleneadipate‐co‐terephthalate) films

AbstractAiming to improve the hydrophilicity, antibacterial activity, cytocompatibility, and hemocompatibility of poly(butyleneadipate‐co‐terephthalate) (PBAT) films, PBAT films were treated with ozone, grafted with chitosan (CS), and followed by covalent immobilization of either heparin (HEP) or hyaluronic acid (HA). The surface graft density of modified PBAT films was detected by X‐ray photoelectron spectroscopy (XPS) and dyeing. The surface roughness of PBAT films was measured using an atomic force microscope (AFM). After immobilizing CS, PBAT films acquired antibacterial activity against Staphylococcus aureus and Escherichia coli. The adsorption of human serum albumin (HSA) and human plasma fibrinogen (HPF) on PBAT–CS–HEP and PBAT–CS–HA films was lower compared to that of native PBAT. Moreover, HEP immobilization could effectively reduce platelet adhesion and prolong the blood coagulation time, thereby improving the blood compatibility of PBAT. In addition, the growth of L929 fibroblasts was improved for HEP or HA immobilized PBAT, suggesting this surface modification was non‐cytotoxic. Furthermore, PBAT–CS–HEP and PBAT–CS–HA exhibited higher cell proliferation than native PBAT. Copyright © 2009 John Wiley & Sons, Ltd.

Swelling and biocompatibility of sodium alginate/poly(γ‐glutamic acid) hydrogels

AbstractSodium alginate (Alg) hydrogel films were crosslinked with either calcium poly(γ‐glutamate) (Ca‐PGA) or CaCl2. The hydrophilicity of the resulting hydrogel films was evaluated through swelling tests, water retention capacity tests, and water vapor permeation tests. The swelling ratio, water retention capacity, and the water vapor transmission rate (WVTR) of Alg/Ca‐PGA were higher than those of Ca‐Alg. The swelling ratio of Alg/Ca‐PGA was 651 and 190% at pH 7.4 and pH 1.2, respectively. The tensile strength of Alg/Ca‐PGA hydrogel was lower than that of Ca‐Alg. The results of hemocompatibility test showed that Alg/Ca‐PGA caused shorter activated partial thromboplastin time (APTT) than Ca‐Alg. Both Ca‐Alg and Alg/Ca‐PGA exhibited almost no adsorption of human serum albumin (HSA), whereas the adsorption of human plasma fibrinogen (HPF) of Ca‐Alg was 10 times of that of Alg/Ca‐PGA. In addition, Alg/Ca‐PGA exhibited platelet adhesion higher than Ca‐Alg. Furthermore, both Alg/Ca‐PGA and Ca‐Alg exhibited no cytotoxicity. Copyright © 2009 John Wiley & Sons, Ltd.

Bacterial cellulose nanofibers for albumin depletion from human serum

Cibacron Blue F3GA (CB) was covalently attached onto the bacterial cellulose (BC) nanofibers for human serum albumin (HSA) depletion from human serum. The BC nanofibers were produced by Acetobacter xylinum in the Hestrin–Schramm medium in a static condition for 14 days. The CB content of the BC nanofibers was 178 μmol/g. The specific surface area of the BC nanofibers was determined to be 914 m 2/g. HSA adsorption experiments were performed by stirred-batch adsorption. The non-specific adsorption of HSA on the BC nanofibers was very low (1.4 mg/g polymer). CB attachment onto the BC nanofibers significantly increased the HSA adsorption (1800 mg/g). The maximum HSA adsorption was observed at pH 5.0. The HSA adsorption capacity decreased drastically with an increase of the aqueous phase concentration of sodium chloride. The elution studies were performed by adding 1 M NaCl to the HSA solutions in which adsorption equilibria had been reached. The elution results demonstrated that the binding of HSA to the adsorbent was reversible. The depletion efficiencies for HSA were above 96.5% for all studied concentrations. Proteins in the serum and eluted portion were analyzed by SDS-PAGE for testing the efficiency of HSA depletion from human serum. Eluted proteins include mainly HSA.

Characterization of Biomaterials by Soft X-Ray Spectromicroscopy.

Synchrotron-based soft X-ray spectromicroscopy techniques are emerging as useful tools to characterize potentially biocompatible materials and to probe protein interactions with model biomaterial surfaces. Simultaneous quantitative chemical analysis of the near surface region of the candidate biomaterial, and adsorbed proteins, peptides or other biological species can be obtained at high spatial resolution via scanning transmission X-ray microscopy (STXM) and X-ray photoemission electron microscopy (X-PEEM). Both techniques use near-edge X-ray absorption fine structure (NEXAFS) spectral contrast for chemical identification and quantitation. The capabilities of STXM and X-PEEM for the analysis of biomaterials are reviewed and illustrated by three recent studies: (1) characterization of hydrophobic surfaces, including adsorption of fibrinogen (Fg) or human serum albumin (HSA) to hydrophobic polymeric thin films, (2) studies of HSA adsorption to biodegradable or potentially biocompatible polymers, and (3) studies of biomaterials under fully hydrated conditions. Other recent applications of STXM and X-PEEM to biomaterials are also reviewed.

Complex pH‐ and temperature‐sensitive swelling behavior of mixed polymer brushes

AbstractThe ability of a mixed polymer brush consisting of poly(N‐isopropyl acrylamide) (PNIPAAM) and poly(acrylic acid) (PAA) to modify physicochemical interfacial properties is presented. The answer of the binary brush toward changes of environmental conditions like temperature, salt concentration, and pH value was investigated by in situ spectroscopic VIS‐ellipsometry as well as AFM and contact angle mesurements in the dry state and compared with the behavior of the corresponding homopolymer brushes. A coupled swelling of PNIPAAm and PAA could be found, leading to a complex pH‐, salt‐, and temperature‐sensitive swelling behavior of these mixed brushes, also depending on the composition of the brush. The complex interaction of the two polymers resulted in new properties of the mixed system. Although the temperature sensitivity of the mixed system was decreased compared with that of the corresponding PNIPAAM brushes, the sensitivity toward pH and salt concentration was amplified compared with that of pure PAA brushes. Additionally it is shown that in spite of the decreased temperature sensitivity of the mixed brush, a temperature‐dependent adsorption of human serum albumin was observed whereas an increased adsorption affinity was found that is not predictable from the adsorption affinity of the corresponding homopolymer brushes. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1606–1615, 2010

Evaluation of protein adsorption on hydrogenated amorphous carbon films by surface plasmon resonance phenomenon

To develop an anti-thrombogenic coating, hydrogenated amorphous carbon ( a-C:H) and related films were studied in terms of their protein adsorption during the initial process in thrombogenesis by surface plasmon resonance (SPR) phenomenon using a multilayer device consisting of an a-C:H layer on Au. Two a-C:H films with different hydrogen contents, a nitrogenated a-C:H ( a-C:N:H) and a fluorinated amorphous carbon ( a-C:F) film were prepared on the Au layer in the multilayer device. Human serum albumin (HSA) in a phosphor buffer (PB) was used as a protein. Na 2HPO 4·12H 2O, NaH 2PO 4·2H 2O and deionized water were mixed to coordinate PB. From the attenuation of reflected light, the SPR angle was determined to the angle at minimum reflection intensity. The observed behavior of the SPR angle indicated that HSA was adsorbed on all films. The SPR angle was analyzed to estimate the multilayer index of the HSA-adsorbed layer on each film. The HSA adsorption ability of both a-C:H and a-C:N:H films was similar, and the absorption ability of the a-C:F film was lower than that of the other films. Hence, the surface polarization dominates the adsorption ability of HSA on a-C:H films and related film.

An X‐ray Spectromicroscopy Study of Albumin Adsorption to Crosslinked Polyethylene Oxide Films

AbstractSynchrotron‐based X‐ray photoemission electron microscopy (X‐PEEM) is used to characterize the near surface composition of polyethylene oxide (PEO) combined with 1.5, 5, and 10 wt.‐% pentaerythritol triacrylate (PETA) crosslinker. It is found that as the concentration of PETA increases, it becomes the dominant component in the top 10 nm of the film surface. The same surfaces are also exposed to human serum albumin (HSA) and the distributions of the protein relative to PEO and PETA measured with X‐PEEM. A positive correlation is found between levels of PETA and HSA at the surface. Above PETA concentrations of 5 wt.‐%, HSA adsorption is significant, which suggests high levels of PETA (often used to immobilize PEO by crosslinking) can significantly reduce the non‐fouling properties of PEO.