SciCombinator

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Concept: Serum albumin

164

In this work, we focused on the label-free detection of simple protein binding using near-infrared light-responsive plasmonic nanoshell arrays with a controlled interparticle distance. The nanoshell arrays were fabricated by a combination of colloidal self-assembly and subsequent isotropic helium plasma etching under atmospheric pressure. The diameter, interparticle distance, and shape of nanoshells can be tuned with nanometric accuracy by changing the experimental conditions. The Au, Ag, and Cu nanoshell arrays, having a 240-nm diameter (inner, 200-nm polystyrene (PS) core; outer, 20-nm metal shell) and an 80-nm gap distance, exhibited a well-defined localized surface plasmon resonance (LSPR) peak at the near-infrared region. PS@Au nanoshell arrays showed a 55-nm red shift of the maximum LSPR wavelength of 885 nm after being exposed to a solution of bovine serum albumin (BSA) proteins for 18 h. On the other hand, in the case of Cu nanoshell arrays before/after incubation to the BSA solution, we found a 30-nm peak shifting. We could evaluate the difference in LSPR sensing performance by changing the metal materials.

Concepts: Nanoparticle, Serum albumin, Surface plasmon resonance, Plasmon, Extraordinary optical transmission, Surface plasmon, Plasma oscillation, Waves in plasmas

31

The response of living systems to nanoparticles is thought to depend on the protein corona, which forms shortly after exposure to physiological fluids and which is linked to a wide array of pathophysiologies. A mechanistic understanding of the dynamic interaction between proteins and nanoparticles and thus the biological fate of nanoparticles and associated proteins is, however, often missing mainly due to the inadequacies in current ensemble experimental approaches. Through the application of a variety of single molecule and single particle spectroscopic techniques in combination with ensemble level characterization tools, we have been able to identify different interaction pathways between gold nanorods and bovine serum albumin depending on the protein concentration. Overall, we found that local changes in protein concentration influence everything from cancer cell uptake to nanoparticle stability and even protein secondary structure. We envision that our findings and methods will lead to strategies to control the associated pathophysiology of nanoparticle exposure in vivo.

Concepts: Protein, Amino acid, Secondary structure, Tertiary structure, Serum albumin

28

Zinc oxide nanoparticles (ZnO NPs) are widely used in medical, industrial and household application owing to excellent antimicrobial property. The biocompatibility of nanoparticles is important for specific biomedical applications. The aim of this study was to stabilize and biofunctionalize ZnO NPs using bovine serum albumin (BSA). Here we have investigated the adsorption behavior of BSA onto ZnO NPs in aqueous solutions. Influence of pH on the adsorption of BSA onto ZnO NPs was also investigated. The study suggests that the electrostatic force of attraction favors the adsorption of BSA onto ZnO NPs. The adsorption data fitted well by Freundlich isotherm compared to Langmuir isotherm. The kinetics of adsorption fitted best to pseudo-second-order.

Concepts: Ultraviolet, Adsorption, Zinc, Serum albumin, Titanium dioxide, Bovine serum albumin, Zinc oxide, Freundlich equation

28

Methoxy poly (ethylene glycol) grafted carboxymethyl chitosan (mPEG-g-CMC) and alginate were chosen as the constituents of hydrogel beads for the construction of an interpenetrating polymeric network matrix. A contrast study between the mPEG-g-CMC hydrogel and mPEG physically mixed with CMC hydrogel was carried out. Bovine serum albumin (BSA) as a model for a protein drug was encapsulated in the hydrogel network, and the drug release properties were studied. The hydrogels prepared by these two methods maintained good pH sensitivity; the loading capacity of the mPEG-g-CMC/alginate hydrogel was enhanced in comparison with that of the hydrogel prepared by physically mixing mPEG. The burst release of the protein was slightly decreased at pH 1.2, while the release at pH 7.4 was improved, suggesting that the mPEG-g-CMC/alginate pH-sensitive hydrogel will be promising for site-specific protein drug delivery in the intestine.

Concepts: Blood, Polymer, Serum albumin, Polysaccharide, Bovine serum albumin, Ethylene glycol, Diol, Polyester

28

Gemini surfactant displayed distinct advantages over monomeric surfactant in the liquid-liquid reverse micellar extraction process. First, less amount of gemini surfactant than monomeric surfactant was needed for transferring almost complete bovine serum albumin (BSA) into organic phase from aqueous phase. Second, the loading capacity of gemini surfactant reverse micelle phase was much higher than that of the corresponding monomeric surfactant reverse micelle. Third, efficient backward extraction (75-92%) of BSA could be effected in a wide pH range from 4 to 9 with gemini surfactant reverse micelle while a pH of ca. 4.3 is prerequisite to the recovery of BSA from monomeric surfactant reverse micelle. So far, the reports about the effect of surfactant structure on protein extraction have been limited. This study indicates the important role of the spacer of gemini surfactant in protein extraction process and may provide more knowledge on how to optimise surfactant structure.

Concepts: Blood, Effect, Serum albumin, PH, Surfactant, Micelle, Bovine serum albumin, Liquid-liquid extraction

28

We report the synthesis and characterization of two nontoxic, thermogelling drug delivery systems which are liquid at room temperatures but become a gel at physiological temperature (37°C) potentially leading to release of a drug molecule. We selected temperature as the stimulus for drug release as it is physiologically invariant. A free radical polymerization of N-isopropylacrylamide (NIPAM) and N-vinylpyrrolidone (VP) was carried out under nitrogen atmosphere in double-distilled water at two different temperatures (30°C and 70°C), and the copolymers obtained were characterized by various analytical techniques. The molar ratios of the two monomers were altered with increasing NIPAM content and their cloud point temperature or least critical solution temperature (LCST) was determined. The copolymer at 9:1 ratio of NIPAM to VP resulted in the formation of nanoparticle-based gel (NG1) at 30°C; however, at 70°C, a microgel (MG1) was formed. The LCST of the nanogel and microgel was 33.5-34°C and 36.5-37°C, respectively. Thus, both the copolymers are water soluble at room temperature, but distinct phases appear at physiological temperatures. We hypothesized that these copolymers on entrapment with a drug could be used for topical application to the skin or eye for controlled drug delivery applications. Toxicological studies revealed that the copolymers are nontoxic in HeLa cells. Finally, our experiments show that a model drug [bovine serum albumin (BSA)] is released at 37°C with zero-order kinetics and confirmed using multiple well-known mathematical models. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.

Concepts: Polymer, Polymer chemistry, Temperature, Solubility, Radical, Serum albumin, Polymerization, Radical polymerization

28

To assess changes in serum albumin concentration (ALB), colloid osmotic pressure (COP), and Doppler blood pressure (DBP) following transfusion of 5% lyophilized canine-specific albumin (CSA) in hypoalbuminemic dogs following surgical source control for septic peritonitis.

Concepts: Blood, Serum albumin, Blood transfusion

28

We design well-defined metal-semiconductor nanostructures using thiol-functionalized CdTe quantum dots (QDs)/quantum rods (QRs) with bovine serum albumin (BSA) protein-conjugated Au nanoparticles (NPs)/nanorods (NRs) in aqueous solution. The main focus of this article is to address the impacts of size and shape on the photophysical properties, including radiative and nonradiative decay processes and energy transfers, of Au-CdTe hybrid nanostructures. The red shifting of the plasmonic band and the strong photoluminescence (PL) quenching reveal a strong interaction between plasmons and excitons in these Au-CdTe hybrid nanostructures. The PL quenching of CdTe QDs varies from 40 to 86 % by changing the size and shape of the Au NPs. The radiative as well as the nonradiative decay rates of the CdTe QDs/QRs are found to be affected in the presence of both Au NPs and NRs. A significant change in the nonradiative decay rate from 4.72×10(6) to 3.92×10(10) s(-1) is obtained for Au NR-conjugated CdTe QDs. It is seen that the sizes and shapes of the Au NPs have a pronounced effect on the distance-dependent energy transfer. Such metal-semiconductor hybrid nanostructures should have great potentials for nonlinear optical properties, photovoltaic devices, and chemical sensors.

Concepts: Optics, Proton, Chemistry, Radioactive decay, Serum albumin, Solar cell, Surface plasmon resonance, Bovine serum albumin

28

Azo dyes are generally resistant to biodegradation due to their complex structures. Acid orange II is one of the most widely used dyes in the textile industry. The influence of bovine serum albumin (BSA) in different concentrations, pH, and time of contact on Orange II was investigated using kinetics and adsorption-isotherm experiments. The results showed that the maximum colour removed from dye/albumin was 99.50% and that a stable dye-protein complex had been formed at pH 3.5 and in a proportion of 1:3 (v/v), respectively. The synthetic effluent did not show toxicity to the microcrustacean Artemia salina, and showed a CL(50) equal to 97 µg/mL to azo dye orange II. Additionally, the methodology was effective in removing the maximum of orange II using BSA by adsorption at pH 3.5 which mainly attracted ions to the azo dye during the adsorption process. This suggests that this form of treatment is economical and easy to use which potentially could lead to bovine serum albumin being used as a sorbent for azo dyes.

Concepts: Serum albumin, Dye, Bovine serum albumin, Azo compound, Pigments, Azo dyes

28

Protein adsorption is one of the key parameters influencing the biocompatibility of medical device materials. This study investigates serum protein adsorption and bacterial attachment on polymer coatings deposited using an atmospheric pressure plasma jet system. The adsorption of bovine serum albumin and bovine fibrinogen (Fg) onto siloxane and fluorinated siloxane elastomeric coatings that exhibit water contact angles (θ) ranging from superhydrophilic (θ < 5°) to superhydrophobic (θ > 150°) were investigated. Protein interactions were evaluated in situ under dynamic flow conditions by spectroscopic ellipsometry. Superhydrophilic coatings showed lower levels of protein adsorption when compared with hydrophobic siloxane coatings, where preferential adsorption was shown to occur. Reduced levels of protein adsorption were also observed on fluorinated siloxane copolymer coatings exhibiting hydrophobic wetting behaviour. The lower levels of protein adsorption observed on these surfaces indicated that the presence of fluorocarbon groups have the effect of reducing surface affinity for protein attachment. Analysis of superhydrophobic siloxane and fluorosiloxane surfaces showed minimal indication of protein adsorption. This was confirmed by bacterial attachment studies using a Staphylococcus aureus strain known to bind specifically to Fg, which showed almost no attachment to the superhydrophobic coating after protein adsorption experiments. These results showed the superhydrophobic surfaces to exhibit antimicrobial properties and significantly reduce protein adsorption.

Concepts: Photosynthesis, Staphylococcus aureus, Staphylococcus, Polymer, Serum albumin, Bovine serum albumin, Contact angle, Fluorocarbon