Adsorption Of Human Serum Proteins Research Articles

Understanding the Influence of Serum Proteins Adsorption on the Mechano‐Bactericidal Efficacy and Immunomodulation of Nanostructured Titanium

AbstractNanostructured surfaces are effective at physically killing bacterial cells, highlighting their prospective application as biomaterials. The benefits of application of mechano‐bactericidal nanostructures as an alternative to chemical functionalisation are well documented, however, the effects of protein adsorption are not well understood. In this work, theoretical and experimental analyses are conducted by studying the adsorption of human serum proteins (HSP) to nanosheet titanium (Ti) and its subsequent effect on the mechano‐bactericidal efficacy toward Staphylococcus aureus and Pseudomonas aeruginosa cells. The nanosheet pattern exhibits enhanced antibiofouling behaviour mantaining high bactericidal efficiency toward both Gram‐negative and Gram‐positive cells in the presence of adsorbed HSP. To ascertain the immunomodulatory response, S. aureus cells are introduced to protein‐conditioned Ti nanosheet surfaces prior to introducing RAW 264.7 macrophages. On the pre‐infected nanostructured surfaces, macrophages exhibit wound healing behaviour with superior activation of M2‐like macrophage polarization and secretion of anti‐inflammatory cytokines. By contrast, macrophages attached to infected smooth surfaces activated the M1‐like polarized phenotype via the high expression of pro‐inflammatory cytokines, indicating persistent inflammation. The outcomes of this work demonstrate the suitability of Ti nanosheets as a potential biomaterial surface whereby the mechano‐bactericidal activity is not compromised by HSP adsorption and, furthermore, positively influenced an anti‐inflammatory immune response.

Bioactive zinc-doped sol-gel coating modulates protein adsorption patterns and in vitro cell responses

Zinc is an essential element with an important role in stimulating the osteogenesis and mineralization and suppressing osteoclast differentiation. In this study, new bioactive ZnCl2-doped sol-gel materials were designed to be applied as coatings onto titanium. The biomaterials were physicochemically characterized and the cellular responses evaluated in vitro using MC3T3-E1 osteoblasts and RAW264.7 macrophages. The effect of Zn on the adsorption of human serum proteins onto the material surface was evaluated through nLC-MS/MS. The incorporation of Zn did not affect the crosslinking of the sol-gel network. A controlled Zn2+ release was obtained, reaching values below 10 ppm after 21 days. The materials were no cytotoxic and lead to increased gene expression of ALP, TGF-β, and RUNX2 in the osteoblasts. In macrophages, an increase of IL-1β, TGF-β, and IL-4 gene expression was accompanied by a reduced TNF-α liberation. Proteomic results showed changes in the adsorption patterns of proteins associated with immunological, coagulative, and regenerative functions, in a Zn dose-dependent manner. The variations in protein adsorption might lead to the downregulation of the NF-κB pathway, thus explain the observed biological effects of Zn incorporation into biomaterials. Overall, these coatings demonstrated their potential to promote bone tissue regeneration.

Influence of buffer solutions in the adsorption of human serum proteins onto layered double hydroxide

The adsorption of human immunoglobulin G (IgG) and human serum albumin (HSA) on a non-calcined Mg-Al layered double hydroxide (3:1 Mg-Al LDH) was studied in batch and fixed bed experiments, focusing on the effect of buffer solution and pH over sorbent uptake. Mg-Al LDH was synthesized and characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherms at −196°C, X-ray photoelectron spectroscopy (XPS), Zero point charge (pHzpc), particle size distribution and Fourier transform infra-red (FTIR). Batch adsorption experiments were performed in order to investigate the effects of pH on IgG and HSA adsorption with different buffers: sodium acetate (ACETATE), sodium phosphate (PHOSPHATE), 3-(N-morpholino) propanesulfonic acid (MOPS), 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES) and trizma-hydrochloric acid (TRIS-HCl). Maximum adsorption capacities estimated by the Langmuir model were 239mgg−1 for IgG and 105mgg−1 for HSA in TRIS-HCl buffer. On the other hand, the highest selectivity for IgG adsorption over HSA was obtained with buffer PHOSPHATE (pH 6.5). The maximum IgG and HSA adsorption uptake in this case were 165 and 36mgg−1, respectively. Fixed bed experiments were carried out with both proteins using PHOSPHATE buffer (pH 6.5), which confirmed that IgG was more selectively adsorbed than HSA on Mg-Al LDH and both could be fully recovered by elution with sodium chloride (NaCl).

Human Serum Protein Adsorption onto Synthesis Nano-Hydroxyapatite

Adsorption of human serum proteins (Albumin and total protein) onto high purity synthesis nano-hydroxyapatite (HA), Ca₁₀(PO₄)₆(OH)₂, has been studied in a wide temperature range by UV-visible spectrophotometer. Adsorption isotherm is basically important to describe how solutes interact with adsorbent, and is critical in optimizing the use of adsorbent. In the present study, the experimental results were fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) models to obtain the characteristic parameters of each model and square of the correlation coefficients (R²). According to the results, the DR isotherm model had the best agreement with the experimental data. The effect of temperature on adsorption of human serum proteins (HSP) onto the synthesized nano-HA was studied. The experimental results indicated that temperature increase generally causes an increase in the adsorption of HSP onto the nano-HA. This is basically due to the effect of temperature on the HSP activity and its diffusion rate on HA surfaces.

Adsorption of human serum proteins onto TREN-agarose: Purification of human IgG by negative chromatography

Tris(2-aminoethyl)amine (TREN) – a chelating agent used in IMAC – immobilized onto agarose gel was evaluated for the purification of IgG from human serum by negative chromatography. A one-step purification process allowed the recovery of 73.3% of the loaded IgG in the nonretained fractions with purity of 90–95% (based on total protein concentration and nephelometric analysis of albumin, transferrin, and immunoglobulins A, G, and M). The binding capacity was relatively high (66.63 mg of human serum protein/mL). These results suggest that this negative chromatography is a potential technique for purification of IgG from human serum.

Adsorption of Human Serum Proteins on Carbonaceous Materials

In this paper, the adsorption of human serum albumin (HSA), human serum fibrinogen (HFG) and human serum immune globulin (IG) on surfaces of diamond like carbon film (DLC), diamond film (DF) and graphite has been studied. The adsorption isotherms of single component protein solution and the competitive adsorption of binary system have been investigated by radioisotope 125 I labeling method. Results showed that (1) the adsorptive amounts of HSA on DLC is more than that of HFG, but the adsorptive amounts of HFG on DF and graphite are apparently more than those HSA; (2) the relative competitive adsorption ability of three proteins on DF and graphite surfaces is HFG > IG > HSA, but that on DLC is HFG ≈ HAS > IG, comparison with HSA, there is no apparent competitive adsorption superiority on DLC for HFG. These results indicated that there is no apparent distinction for the adsorption of three human serum proteins on DLC, but the adsorption of HFG on DF and graphite takes precedence in varying degrees. It probably makes rational explanation for the result of blood-compatibility tests in vitro that DLC is good, but DF and graphite are worse.

Two-step elution of human serum proteins from different glass-modified bioactive surfaces: a comparative proteomic analysis of adsorption patterns.

Plasma protein adsorption patterns on surfaces may give vital information to evaluate biocompatibility of biomaterials designed for direct blood-contacting applications or tissue integration. Adsorption of human serum proteins on four different types of biomaterials (glass, aminosilanized glass, hyaluronan and sulfated hyaluronan) was analyzed by two-dimensional electrophoresis. Desorption of proteins from the surfaces was first classically achieved by sodium dodecyl sulfate (SDS) elution. We introduced a second elution step (by use of isoelectric focusing (IEF) sample buffer consisting of urea, 3-[(3-cholamidopropyl)dimethylammonio]-1-propansulfonate, and dithioerythritol) which allows more stringent elution conditions and is a tool to evaluate the protein adsorption strength to biomaterials. Moreover, the two-step elution may discriminate between irreversible and reversible adsorption of plasma proteins for biomaterials, thus helping to elucidate the structure of protein multilayers which form a complex system at the surfaces. The IEF sample buffer proved not to alter the biomaterial structure and integrity. Hydrophobic bonds resulted to be the main strength driving protein adsorption onto our biomaterials. Apolipoproteins were the most important proteins interacting with the surfaces suggesting that high-density lipoprotein (HDL) particles could play a role in biocompatibility due to their beneficial effects on endothelial cells.

Cyanocarbons as ligands for electron donor acceptor chromatography of human serum proteins

The adsorption of human serum proteins to mono-, di- and tri-cyanocarbon ligands was studied in the presence of the water-structuring salt Na 2SO 4. All of the ligands adsorbed proteins to varying degrees when coupled to agarose via a divinylsulfone-derived spacer arm (DVS), whereas an insignificant or very low protein adsorption capacity occurred when the ligands were coupled through the bisoxirane-derived spacer arm. Studies of the DVS-coupled cyanocarbons showed that adsorption capacity increases with the number of cyano substituents carried by the ligand. The selectivity toward human serum proteins appeared to be similar to that of other electron acceptor ligands, but different from that of hydrophobic ligands. Tricyanoaminopropene-DVS-agarose was found to be the most potent protein adsorbent.

Thiophilic adsorption - a new method for protein fractionation

Divinylsulphone-activated agarose to which mercaptoethanol is coupled showed very selective group adsorption of human serum proteins, in particular the immunoglobulins. The adsorption increases markedly in the presence of high concentrations of neutral water-structure forming salts and is distinct from adsorptions based on hydrophobic interaction. A characteristic feature of this new type of adsorbent is the structure of the groups attached to the polymer, XXX, i.e., R-S-CH 2-CH 2-SO 2-CH 2-CH 2-O-XXX, where R is a small aliphatic residue. Our results indicate that the thioether sulphur and the adjacent sulphone group act cooperatively and are apparently necessary to maintain the distinct behaviour of such absorbents. Divinylsulfone Immunoglobulin Affinity chromatography Hydrophobic interaction (salting-out) Serum fractionation