Adsorption Of Albumin Protein Research Articles

In-vitro Safety Assessment of Ultrasmall Gold Nanoparticles for Preclinical Drug Delivery Applications

Background: The development of safe and biocompatible nanoparticles has always been a major concern in nanomedicine applications. Various studies on the size-dependent toxicity of na-noparticles have been reported but are still controversial. The potential of small-sized nanoparticles can be utilized for imaging and diagnostics. However, insufficient toxicity data on these nanoparti-cles prevents researchers from utilizing their potential in diagnostics. More studies are needed on the toxicity of small-sized nanoparticles to present unanimous report for safe systemic use. The pre-sent study aimed to investigate the toxicity concerns of very small-sized AuNPs (2 ± 0.5 nm, 5 ± 1 nm, and 10 ± 2 nm) and provide a platform for their safe in vivo use. Methods: The cellular interactions of these three small-sized AuNPs with regard to cytotoxicity were investigated on hepatocellular carcinoma (HepG2) and epithelial kidney (HEK-293) cell lines. The cytotoxicity investigation of both cell lines was done through MTT assays, PI & DAPI, and cy-tology. Cellular stress was investigated by Catalase, TBARS, GSH, SOD & ROS parameters. The AuNPs incubated cells were also assessed for immunogenicity by ELISA, protein interaction by BSA, and cellular internalization by TEM (Edax). Results: All three-sized AuNPs were not toxic on cell viability, apoptosis, necrosis, or cytology as-sessment. No oxidative stress was noted in both cell types in the presence of 2 and 5-nm-sized AuNPs, whereas 10 nm-sized AuNPs showed little oxidative stress. AuNPs of size 2 and 5 nm were immunologically inert, but 10 nm-sized AuNPs elicited interleukin (IL-4 and IL-10) and interferon IFN gamma response. AuNPs of sized 2 nm showed 4 times the adsorption of albumin protein as compared to AuNPs of sized 5 nm. The TEM micrographs and peak of gold in the Edax graph con-firmed the presence of AuNPs in cells. Conclusion: Our results are suggestive of utilizing the potential of these three-sized AuNPs safely in preclinical drug delivery applications.

Influence of titanium nanoscale surface roughness on fibrinogen and albumin protein adsorption kinetics and platelet responses.

Biomaterials with nanoscale topography have been increasingly investigated for medical device applications to improve tissue-material interactions. This study assessed the impact of nanoengineered titanium surface domain sizes on early biological responses that can significantly affect tissue interactions. Nanostructured titanium coatings with distinct nanoscale surface roughness were deposited on quartz crystal microbalance with dissipation (QCM-D) sensors by physical vapor deposition. Physico-chemical characterization was conducted to assess nanoscale surface roughness, nano-topographical morphology, wettability, and atomic composition. The results demonstrated increased projected surface area and hydrophilicity with increasing nanoscale surface roughness. The adsorption properties of albumin and fibrinogen, two major plasma proteins that readily encounter implanted surfaces, on the nanostructured surfaces were measured using QCM-D. Significant differences in the amounts and viscoelastic properties of adsorbed proteins were observed, dependent on the surface roughness, protein type, protein concentration, and protein binding affinity. The impact of protein adsorption on subsequent biological responses was also examined using qualitative and quantitative in vitro evaluation of human platelet adhesion, aggregation, and activation. Qualitative platelet morphology assessment indicated increased platelet activation/aggregation on titanium surfaces with increased roughness. These data suggest that nanoscale differences in titanium surface roughness influence biological responses that may affect implant integration.

Response of Osteoblasts on Amine-Based Nanocoatings Correlates with the Amino Group Density.

Increased life expectancy in industrialized countries is causing an increased incidence of osteoporosis and the need for bioactive bone implants. The integration of implants can be improved physically, but mainly by chemical modifications of the material surface. It was recognized that amino-group-containing coatings improved cell attachment and intracellular signaling. The aim of this study was to determine the role of the amino group density in this positive cell behavior by developing controlled amino-rich nanolayers. This work used covalent grafting of polymer-based nanocoatings with different amino group densities. Titanium coated with the positively-charged trimethoxysilylpropyl modified poly(ethyleneimine) (Ti-TMS-PEI), which mostly improved cell area after 30 min, possessed the highest amino group density with an N/C of 32%. Interestingly, changes in adhesion-related genes on Ti-TMS-PEI could be seen after 4 h. The mRNA microarray data showed a premature transition of the MG-63 cells into the beginning differentiation phase after 24 h indicating Ti-TMS-PEI as a supportive factor for osseointegration. This amino-rich nanolayer also induced higher bovine serum albumin protein adsorption and caused the cells to migrate slower on the surface after a more extended period of cell settlement as an indication of a better surface anchorage. In conclusion, the cell spreading on amine-based nanocoatings correlated well with the amino group density (N/C).

PCL/Si-Doped Multi-Phase Calcium Phosphate Scaffolds Derived from Cuttlefish Bone.

Increasing attention is focused on developing biomaterials as temporary scaffolds that provide a specific environment and microstructure for bone tissue regeneration. The aim of the present work was to synthesize silicon-doped biomimetic multi-phase composite scaffolds based on bioactive inorganic phases and biocompatible polymers (poly(ε-caprolactone), PCL) using simple and inexpensive methods. Porous multi-phase composite scaffolds from cuttlefish bone were synthesized using a hydrothermal method and were further impregnated with (3-aminopropyl)triethoxysilane 1–4 times, heat-treated (1000 °C) and coated with PCL. The effect of silicon doping and the PCL coating on the microstructure and mechanical and biological properties of the scaffolds has been investigated. Multi-phase scaffolds based on calcium phosphate (hydroxyapatite, α-tricalcium phosphate, β-tricalcium phosphate) and calcium silicate (wollastonite, larnite, dicalcium silicate) phases were obtained. Elemental mapping revealed homogeneously dispersed silicon throughout the scaffolds, whereas silicon doping increased bovine serum albumin protein adsorption. The highly porous structure of cuttlefish bone was preserved with a composite scaffold porosity of ~78%. A compressive strength of ~1.4 MPa makes the obtained composite scaffolds appropriate for non-load-bearing applications. Cytocompatibility assessment by an MTT assay of human mesenchymal stem cells revealed the non-cytotoxicity of the obtained scaffolds.

Multifarious anti-biofouling bioprosthetic heart valve materials with the formation of interpenetrating polymer network structures

The bioprosthetic heart valve (BHV) has attracted considerable attention in clinical practice. However, complications of the BHV such as thrombosis, calcification, and early deterioration after implantation have limited further applications. In the present study, we provide a strategy to fabricate an anti-biofouling BHV by constructing interpenetrating polymer network structures on both inner and outer valve materials. We systematically investigated the morphologies, wetting properties, elemental compositions, stability of the extracellular matrix, transparency, mechanical properties, and anti-biofouling properties (e.g., anti-cell adhesion, resistance to bovine serum albumin protein adsorption, anticoagulant properties, and anti-calcification properties) of the modified BHV via both in vitro and in vivo experiments. Compared to the BHV without coating treatment, treated with heparin, or treated with a hydrophobic polydimethylsiloxane coating, the BHV treated with a hydrophilic coating containing both polyacrylic acid and polydimethylsiloxane exhibited better multifarious anti-biofouling properties. Our findings provide a method for the preparation of multi-antifouling medical materials with better synergistic hemocompatibility and anti-calcification.

Role of phosphate, calcium species and hydrogen peroxide on albumin protein adsorption on surface oxide of Ti6Al4V alloy

Protein adsorption and its conformational arrangements on the surface of metallic biomaterials directly influence the biocompatibility and the degradation process during the implant lifetime. However, the presence of various species such as phosphates, calcium and hydrogen peroxide (H2O2) in the human body not only control the electrochemical interactions on the biomaterial surface but could also modify the protein adsorption process and its impact on the metal degradation. To this aim bovine serum albumin (BSA) protein adsorption, morphology, surface potential and its impact on the corrosion resistance of a Ti6Al4V alloy was investigated in different solutions, including a sodium chloride (NaCl), a phosphate-buffered saline (PBS) and Hank's physiological solutions. The results indicated that the alloy in PBS solution was more resistant to corrosion than that in Hanks’ or NaCl solutions. Mott–Schottky analysis demonstrated that all solutions containing BSA and H2O2 had the highest donor charge carrier. Scanning electron microscopy (SEM) and surface potential images indicated that by changing the physiological solutions from NaCl to PBS and then to Hanks’, the morphology of adsorbed BSA protein changed from a globular or unfolded shape to a large micronetwork and then to a fine micro-nanonetwork, accompanied by a gradual increase in the surface potential. Moreover, it was figured out that the BSA protein/substrate interface and the top surface of the BSA protein were susceptible to corrosion initiation owing to the different surface potentials and thus are preferable sites for the adsorption of corrosive counterions, e.g., Cl−.

RETRACTED ARTICLE: The structure and biological properties of clustered anatase/rutile nanowire array–modified titanium surface

Understanding of the complicated interactions between biomaterials and cells can accelerate biomedical developments. Recently, many in vitro studies have emphasized the biological features of nanowires (NWs) on the cell’s early response. A type of unique clustered anatase/rutile NWs (ARNWs) was generated using a simple hydrothermal reaction on titanium in the present study. The aim of this study is to determine whether the ARNWs is beneficial for the enhancement of biological capacity. Clustered ARNWs with a diameter of 200 nm were grown on titanium disks via a three-step synthesis process. Three different types of NWs were generated during the production process, displaying different biological characteristics but similar surface topography and wettability. All of the NW surfaces remarkably accelerated the adsorption of albumin protein; however, compared to the ARNWs, a relatively low level of cell attachment and proliferation occurred on the surfaces of sodium titanate NWs (STiNWs) and H2Ti2O5 nanowires (HTiNWs). The data indicated that the surface titanium oxide crystal structure plays an important role in the cell’s early response. To some extent, the generation of anatase and rutile of the ARNWs compensated for the cell-repelling properties. The crystal structure and potential larger loading capacity of the ARNWs face challenges for enhanced cellular adaptation which could improve its clinical potential.

One pot preparation of polysulfone-amino functionalized SiO2 nanoparticle ultrafiltration membranes for water purification

Highly hydrophilic and fouling resistant polysulfone (PSF) membranes were prepared via one pot methodology by simultaneous phase inversion and nanoparticle formation. Membrane morphology, hydrophilicity, and surface charge behavior were thoroughly characterized by scanning electron microscopy, atomic force microscopy, contact angle, and zeta potential measurements. The SiO2-NH2 nanoparticle distribution in membrane matrix was also investigated by energy dispersive X-ray spectroscopy and transmission electron microscopy. The water purification performances, some of the membranes flux, rejection, and flux recovery, were evaluated by ultrafiltration of bovine serum albumin protein, Congo red, and methylene blue dyes under dead end mode. The fouling tendency of the membrane was evaluated by bovine serum albumin protein adsorption and ultrafiltration. The properties of the prepared membranes could be tuned by varying the SiO2-NH2 concentration. The nanocomposite membranes exhibited superior water permeation, rejection, and antifouling performance as compared to neat PSF membranes. Hydrophilicity was increased due to amino functionalized SiO2 particles, leading to up to 7-fold increase in water flux and more than 93% protein rejection efficiency with PSF-APTEOS-20 and -10 membranes, respectively. Overall, this work proves an easy and straightforward method for nanocomposite ultrafiltration membrane preparation with good separation and filtration efficiency.

Synthesis of biofunctional coating for a TiZr alloy: Surface, electrochemical, and biological characterizations

This study formed a biofunctional coating for a Ti15Zr alloy to improve the surface characteristics, the electrochemical behavior, and the biological properties of this implant material. Ti15Zr discs (15 mm in diameter × 1 mm thickness) were obtained in three versions: machined, SLA®-treated (control groups), and modified by plasma electrolytic oxidation (PEO) (experimental group). Surface features such as topography, composition, surface roughness, surface free energy, and hardness were assessed. Electrochemical tests were conducted with body fluid solution (pH 7.4). The albumin protein adsorption was measured by the bicinchoninic acid method, and the adhesion of Streptococcus sanguinis was determined. The surface treatments modified the material’s topography. SLA promoted surface roughness higher than that of the other groups, whereas PEO surfaces presented the highest values of hardness and surface free energy. PEO increased the polarization resistance and the corrosion potential, and decreased capacitance and corrosion current density values. In addition, plasma treatment improved the albumin adsorption without being favorable to biofilm adhesion. PEO appears to be the most promising alternative for Ti15Zr alloys, since it improved surface characteristics and electrochemical behavior, as well as enhancing the adsorption of albumin on the material surface with fewer tendencies to bacterial adhesion.

Novel mussel-inspired Ti-6Al-4V surfaces with biocompatibility, blood ultra-drag reduction and superior durability

In order to develop new Ti-based biomaterials with biocompatibility, blood ultra-drag reduction and superior durability, a novel fabrication combining simple electrochemical and chemical processes was proposed. After being modified by C14H19F13O3Si (FAS), a biocompatible TiO2-SiO2-polydopamine composite surface on Ti-6Al-4V substrate was obtained. The biocompatibility was evaluated using a series of in vitro test, revealing that compared with Ti-6Al-4V alloys, the surfaces exhibited a number of bio-advantages such as anti-platelet aggregation, anti-bovine serum albumin protein adsorption, a lower hemolysis rate (~0.7%) and non-cytotoxicity (the cell viability >88%). The test of human microvascular endothelial cells (HMEC) cultured on the specimens for 48h showed better cell proliferation of the surface. Moreover, we explored the blood dynamic characteristics of titanium alloy substrate biomaterial for the first time, with a focus on the effects of dopamine-reactant concentration on blood flow resistance. The results showed that, compared to titanium alloy material, the TiO2-SiO2 surface modified by 4mg·mL−1 dopamine solution displayed the optimal blood drag reduction characteristics, reaching a 76% drag reduction. After a 2m (800 meshes, 3500Pa) sandpaper abrasion test, the surface still maintained a superior repellency of blood (contact angles>150°, sliding angles<10°). This practical method may expand the applications of biomedical implantation materials.

Reduced Protein Adsorption on Plasma Polymer Films Comprising Hydrophobic/Hydrophilic Vertical Chemical Gradients

The adsorption of albumin protein (bovine serum albumin) from aqueous solution onto different types of cross-linked plasma polymer films is studied with unexpected results. Films are plasma-polymerized from a methylated siloxane precursor with controlled oxygen addition to obtain variable oxygen/carbon ratios, which adjust the hydrophobic–hydrophilic balance. Using the same technique vertical chemical gradients are generated with a hydrophobic surface termination and gradual transition to the hydrophilic plasma polymer over a few nanometers in depth. Remarkably, protein adsorption is significantly reduced on such gradient surfaces, suggesting existence of an energetic contribution from the sub-surface region.

Multivalent grafting of hyperbranched oligo- and polyglycerols shielding rough membranes to mediate hemocompatibility.

Hemocompatible materials are needed for internal and extracorporeal biomedical applications, which should be realizable by reducing protein and thrombocyte adhesion to such materials. Polyethers have been demonstrated to be highly efficient in this respect on smooth surfaces. Here, we investigate the grafting of oligo- and polyglycerols to rough poly(ether imide) membranes as a polymer relevant to biomedical applications and show the reduction of protein and thrombocyte adhesion as well as thrombocyte activation. It could be demonstrated that, by performing surface grafting with oligo- and polyglycerols of relatively high polydispersity (>1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials.

Evaluation of the functionality of biodegradable polymeric platforms for drug delivery systems

We present the development of a drug-loaded triple-layer platform consisting of thin film biodegradable polymers, in a properly designed form for the desired gradual degradation. Poly(dl-lactide-co-glycolide) (PLGA (65:35), PLGA (75:25)) and polycaprolactone (PCL) were grown by spin coating technique, to synthesize the platforms with the order PCL/PLGA (75:25)/PLGA (65:35) that determine their degradation rates. The outer PLGA (65:35) layer was loaded with dipyridamole, an antiplatelet drug. Spectroscopic ellipsometry (SE) in the Vis-far UV range was used to determine the nanostructure, as well as the content of the incorporated drug in the as-grown platforms. In situ and real-time SE measurements were carried out using a liquid cell for the dynamic evaluation of the fibrinogen and albumin protein adsorption processes. Atomic force microscopy studies justified the SE results concerning the nanopores formation in the polymeric platforms, and the dominant adsorption mechanisms of the proteins, which were defined by the drug incorporation in the platforms.

Cryogenically cured hydroxyapatite–gelatin nanobiocomposite for bovine serum albumin protein adsorption and release

This research paper presents the first results on the protein adsorption and release kinetics and in vitro biodegradability of cryogenically cured hydroxyapatite–gelatin based micro/macroporous scaffolds (CHAMPS). While the adsorption and release of bovine serum albumin (BSA) protein exhibits steady state behavior over an incubation period of up to 10 days, Fourier transform infrared (FT-IR) analysis importantly confirms the absence of any change in the secondary structure of BSA proteins due to interaction with the CHAMPS scaffold. The compression properties of the CHAMPS scaffold with interconnected porosity (pore size ∼50–200 μm) is characterized by a non-linear stress–strain response with a strength close to 5 MPa and a maximum strain of up to 24%. The slow but systematic increase in weight loss over a period of 7 days as well as apatite layer formation indicates its good bioactivity. The extensive micro-computed tomography (micro-CT) analysis establishes cancellous bone-like highly interconnected and complex porous architecture of the CHAMPS scaffold. Importantly, the excellent adsorption (up to 50%) and release (up to 60% of adsorbed protein) of BSA has been uniquely attributed to the inherent porous microstructure of the CHAMPS scaffold. Overall, the present study provides an assessment of the interaction of protein with the gelatin–hydroxyapatite macroporous scaffold in vitro, as well as reporting for the first time the efficacy of such scaffolds to release 60% of BSA loaded onto the scaffold in vitro, which is significantly higher than earlier literature reports.

Surface-functionalization of PDMS for potential micro-bioreactor and embryonic stem cell culture applications.

This study presents a novel and inexpensive method to prepare a disposable micro-bioreactor for stem cell expansion. The micro-bioreactor was fabricated in the form of a fixed bed bioreactor with a microchannel reactor bed. The micro-bioreactor was constructed from polydimethylsiloxane (PDMS), and the microchannel was functionalized to enable cell adhesion and resistance to bovine serum albumin protein adsorption. The PDMS reactor bed surface was activated by oxygen plasma, then aminized with trimethoxysilylpropyl(polyethyleneimine), followed by grafting with carboxylmethyl cellulose (CMC) and gelatin in sequence. The functionalized PDMS surface demonstrated improved hydrophilicity and antifouling properties. The grafting of gelatin promoted cell adhesion. The functionalized surface was found to be biocompatible with MDA-MB-231 and Oct4b2 cells and was demonstrated to facilitate cell proliferation. The expanded Oct4b2 cells retained their proliferation potential, undifferentiated phenotype and pluripotency.

Competitive Protein Adsorption of Albumin and Immunoglobulin G from Human Serum onto Polymer Surfaces

Competitive protein adsorption from human serum onto unmodified polyethylene terephthalate (PET) surfaces and plasma-polymerized PET surfaces, using the monomer diethylene glycol vinyl ether (DEGVE), has been investigated using radioactive labeling. Albumin and immunoglobulin G (IgG) labeled with two different iodine isotopes have been added to human serum solutions of different concentrations, and adsorption has been performed using adsorption times from approximately 5 s to 24 h. DEGVE surfaces showed indications of being nonfouling regarding albumin and IgG adsorption during competitive protein adsorption from diluted human serum solutions with relatively low protein concentrations, but the nonfouling character was weakened when less diluted human serum solutions with higher protein concentrations were used. The observed adsorption trend is independent of adsorption time, indicating that the protein concentration has a stronger influence on observed adsorption characteristics of the material than the adsorption time has.

Preparation of albumin–ferrite superparamagnetic nanoparticles using reverse micelles

AbstractBACKGROUND: Micellar systems are widely applied as reactors to encapsulate inorganic nanoparticles in polymeric materials. However, only low inorganic contents and microscale dimensions are often achieved.RESULTS: The adsorption of albumin protein on ferrite nanoparticles permits to increase the stability of inorganic dispersions in water by inhibiting particle flocculation. Subsequent glutaraldehyde addition induces protein crosslinking and ferrite entrapment. Polymer–ferrite composite nanoparticles were obtained in this way. The magnetic albumin nanoparticles (25 nm mean diameter) obtained contain about 40 wt% of ferrite and show superparamagnetic behaviour. The composite powder was successfully functionalized with a model drug and the biological activity was evaluated.CONCLUSION: Using a reverse micelle approach, ferrite–albumin composite nanoparticles with a high inorganic content were obtained. The method permits the formulation of biocompatible magnetic particles of nanoscale dimensions. The exhibited superparamagnetic behaviour permits to hypothesize an application of the powder composite as a carrier in biomedical technologies. Copyright © 2009 Society of Chemical Industry

Human Serum Albumin Adsorption Study on 62-MHz Miniaturized Quartz Gravimetric Sensors

We have designed and fabricated 25-microm-thick quartz resonators operating at a fundamental resonance frequency of approximately 62 MHz. The results show a substantial increase in the mass sensitivity compared to single monolithic commercial resonators operating at lower frequencies in the approximately 5-10-MHz range. The overall performance of the micromachined resonators is demonstrated for the example of human serum albumin protein adsorption from aqueous buffer solutions onto gold electrodes functionalized with self-assembled monolayers. The results show a saturation adsorption frequency change of 6.8 kHz as opposed to 40 Hz for a commercial approximately 5-MHz sensor under identical loading conditions. From the analysis of the adsorption isotherm, the equilibrium adsorption constant of the adsorption of the protein layer was found to be K = 8.03 x 10(6) M(-1), which is in agreement with the values reported in the literature. The high sensitivity of the miniaturized QCM devices can be a significant advantage in both vapor and solution adsorption analyses.

Fluorescence From Metallic Silver and Iron Nanoparticles Prepared by Exploding Wire Technique

The observation of intense visible fluorescence from silver and iron nanoparticles in different solution phases and surface capping is reported here. Metallic silver and iron nanoparticles were obtained by exploding pure silver and iron wires in pure water. Bovine serum albumin protein adsorption on the silver nanoparticles showed an enhanced fluorescence. The presence of poly-vinyl pyrrolidone polymer in the exploding medium resulted in a stabilized growth of iron nanoparticles with enhanced fluorescence intensity. The fluorescence was found to be surface /interface dependant. The fluorescence is attributed to electronic transitions among characteristic interface energy bands. The magnetic nature of iron nanoparticles was confirmed from the hysteresis measurements.

Techniques for patterning and guidance of primary culture neurons on micro-electrode arrays

In this work, two different micro-patterning methods for use in the growth guidance of dissociated primary culture neuron cells are compared: open chemically patterned growth substrates and enclosed micro-fluidic channels. Open, chemically patterned growth substrates are prepared by photolithographically patterning perfluoropolymer barrier structures on glass substrates. Neural pathways are created when poly-l-lysine is selectively adsorbed on the glass to form a cytophilic growth matrix. Adsorption of albumin proteins on the perfluoropolymer regions renders the surface cytophobic. In a second method, a three-dimensional micro-fluidic system, fabricated from PDMS is tested as a way to guide neural growth through total confinement and for cell placement. Both of these methods are tested for alignment and compatibility on a commercially available micro-electrode array (MED64). Biological culture and imaging techniques are considered.