Reduced graphene oxide-grafted bovine serum albumin/bredigite nanocomposites with high mechanical properties and excellent osteogenic bioactivity for bone tissue engineering

The optimization of the scaffolds to provide a suitable matrix and accelerate the regeneration process is vital for bone tissue engineering.However,poor mechanical and biological characteristics remain the primary challenges that must be addressed.For example,although bredigite(Br)has shown great potential for application in bone tissue engineering,it easily fails in replacement.In the present work,these challenges are addressed by reinforcing the Br matrix with nanosheets of graphene oxide(rGO)that have been reduced by bovine serum albumin(BSA)in order to enhance the mechanical properties and biological behavior.The reduction of graphene oxide by BSA improves the water stability of the nanosheets and provides an electrostatic interaction between theBSA-rGO nanosheets and theBr particles.The high thermal conductivity of theBSA-rGO nanosheets decreases the porosity of the Br by transferring heat to the core of the tablet.Furthermore,the addition of BSA-rGO nanosheets into the Br matrix enhances the adhesion of G-292 cells on the surface of the tablets.These findings suggest that the tablet consisting of BSA-rGO-reinforced Br has encouraging potential for application in bone tissue engineering.

STUDIES ON THE COMPETITION FOR CADMIUM ION BETWEEN CHELATING AGENTS AND BOVINE SERUM ALBUMIN

Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in the presence and absence of chelating agents,can be used as the criterion to evaluate the mobilizing capability of chelating agent.The F values determined experimentally lead to a mobilizing capability order:DTPA>EDTA>EGTA>NTA>TR1EN>PEN>CYS>HIS>SAThe polyaminopolycarboxylate type chelators mobilize cadmium effectively.A linear relationship was found between 1gF and lg k’CdL (conditional stability constant of the cadmium chelate).

Photochemical Reaction of 9,10-Anthraquinone Labeled Bovine Serum Albumin Conjugate

Bovine serum albumin (BSA) was labeled with 9, 10-anthraqinone and the photochemical fluorimetric reactivity of the covalently conjugated 9,10-anthraquinone was remarkably improved.The mechanism for the enhancement in the photochemical reactivity of conjugated 9,10- anthraquinone with BSA was

Ultralow fouling electrochemical detection of uric acid directly in serum based on phase-transited bovine serum albumin and conducting polymer

Electrochemistry with antifouling sensing interfaces that effectively resist the adsorption of nonspecific biomolecules provides a powerful mean for the accurate and sensitive detection of disease biomarkers tive dete in complex biofluids.However.there are few strategies to acquire a stable and solid antifouling coat-ing on any substrate by a simple way.Herein,a simple one-step assembly methød has been adopted to construct phase-transited bovine serum albumin(PTB)antifouling Layers.Prior to construction of the an-tifouling layers.the poly(3,4-ethylenedioxythiophene)(PEDOT)doped with 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(ionic liquid,IL)were firstly electrodeposited on bare electrodes,en-dowing good conductiviry and catalytic capability for the developed sensor.Subsequently.with the assist of tris(2-carboxyethyl)phosphine(TCEP)the disulfide bonds of bovine serum albumin(BSA)were re-Im alb duced to form PTB,which can be coated on the PEDOT-It modified electrode to construct an antifouling electrochemical senor(PTB/PEDOT-ILCCE)for the detection of uric acid(UA)in human serum.The UA sensor demonstrated a good linear range from 1.11 umol/L to 798.9 umol/L with a high sensltivity of0,556 jA umolL^(-1)cm^(-2).The combination of conducting polymers with one-step assembly of PTB offers a universal and rellable method før the modification of various electrodes to determine target molecules in complex human body fluids.

Spectroscopic and dynamic light scattering studies of the interaction between pterodontic acid and bovine serum albumin

Pterodontic acid(PA)has been isolated from Laggera pterodonta,a Chinese herbal medicine,and shown to possess antibacterial activity in vitro.To facilitate its preclinical development,the interaction between PA and bovine serum albumin(BSA)was studied using a fluorescence quenching technique,ultraviolet–visible spectrophotometry and dynamic light scattering(DLS).At temperatures of 297 K and 310 K and an excitation wavelength of 282 nm,the fluorescence intensity of BSA decreased significantly with increasing concentration of PA attributed to the formation of a PA–BSA complex.The apparent binding constant,number of binding sites and corresponding thermodynamic parameters were calculated and the main intermolecular attraction shown to result from hydrogen bonding and van der Waals forces.Synchronous fluorescence spectrometry revealed that the binding site in the complex approached the microenvironment of Trp and three-dimensional fluorescence spectroscopy showed the binding induced conformational changes in BSA.Using DLS,increasing PA concentration was shown to cause a gradual increase in hydrodynamic diameter and significant aggregation of the complex.

Preliminary study of adsorption behavior of bovine serum albumin(BSA) protein and its effect on antibacterial and corrosion property of Ti-3Cu alloy

The adsorption behavior, antibacterial, and corrosion properties of a Ti-3 Cu alloy were studied in a phosphate-buffered saline solution containing 0, 1, 3, and 6 gL^(-1) bovine serum albumin protein at 37℃ and pH = 7.4(±0.2). The protein adsorption behavior was examined via cyclic voltammetry, secondary ions mass spectroscopy(SIMS), and angle-resolved X-ray photoelectron spectroscopy(ARXPS). The corrosion property was analyzed by the open circuit potential(OCP), potentiodynamic polarization(PD),and electrochemical impedance spectroscopy(EIS) examinations. The antibacterial test was conducted according to the GB/T 21510 China Standard. It was observed that the surface charge density(QA DS) was directly proportional to the amount of the adsorbed BSA protein, signifying that the protein adsorption was accompanied by the charge transfer, pointing to chemisorptions phenomena. BSA amino groups and other organic species were observed in the surface analysis examinations. It was shown that the formation of barrier complexes between the TiO_(2) oxide-layer and PBS solution resulted in decreasing the release of Cu-ions, which consequently reduced the antibacterial activity. On the other hand, these barrier complexes improved the corrosion resistance by increasing the charge transfer resistance and double-layer capacitance of the Ti-3 Cu alloy.

Preparation of MnO2-impregnated carbon-coated Fe3O4 nanocomposites and their application for bovine serum albumin adsorption

MnO2-impregnated carbon-coated Fe3 O4(Fe3O4/C/MnO2)nanocomposites with a good core-shell structure were prepared by direct oxidation of carbon-coated Fe3 O4(Fe3O4/C)microspheres with KMnO4 in alkaline solution and applied to adsorb bovine serum albumin(BSA).X-ray diffraction(XRD),transmission electron microscope(TEM),Fourier transform infrared spectrometer(FTIR),vibrating sample magnetometer(VSM)and thermogravimetric analyzer(TGA)tests show that Fe3O4/C microspheres were newly functionalized via the oxidation by KMnO4.Fe3O4/C/MnO2 nanocomposites exhibit a higher adsorption capacity for BSA than Fe3O4/C microspheres and the maximum adsorption of BSA on them occurs at pH 4.7,which is the isoelectric point of BSA.Langmuir isotherm model describes the adsorption of BSA better than Freundlich model and Temkin model,and the kinetics data fit well with the pseudo-second-order model.

Epicatechin attenuates lead(Pb)-induced cognitive impairment in mice:regulation on Nrf2 signaling pathway,and interference on the interaction between Pb with albumin

Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 weeks.Morris water maze test showed that EC could improve memory dysfunction induced by Pb.EC antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in mice.In vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of EC.EC was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.

(E)-2-Benzylidenecycloalkanones XII.*Kinetic Measurement of Bovine and Human Serum Albumine Interaction with Selected Chalcones and Their Cyclic Chalcone Analogues by UV Spectrophotometry

UV-VIS spectroscopic investigations of interaction of bovine and human serum albumin with selected chalcones (1) and their cyclic chalcone analogues: (E)-2-(4’-X-benzylidene-1-tetralones (3), benzosuberones (4) with dimethylamino and methoxy substituents and (E)-2-(2’,4’-dimethox- ybenzylidene)-1-indanone (2) were performed in polar respiration medium. Absorption maxima of the tested compounds were investigated in the presence of bovine and human serum albumin at the 0, 10, 30 and 60 minute timepoints of the interaction. The absorbance of all studied compounds in the presence of proteins decreased after one hour of the reaction. Molecule 4a showed the strongest and fastest kinet initial interaction with both albumins.

Bovine Serum Albumin Detection by Graphene Oxide Coated Long-Period Fiber Grating

A biosensor for bovine serum albumin(BSA)detection by graphene oxide(GO)functionalized micro-taped long-period fiber grating(GMLPG)was demonstrated.The amide bond connected between the GO and BSA enabled the BSA to attach onto the fiber surface,which changed the effective refractive index of the cladding mode and characterized the concentration of the BSA.This real-time monitoring system demonstrated a sensing sensitivity of 1.263 nm/(mg/mL)and a detection limit of 0.043 mg/mL.Moreover,it illustrated superior measurement performance of higher sensitivity in the presence of glucose and urea as the interference,which showed static sensitivities of~1.476 nm/(mg/mL)and 1.504 nm/(mg/mL),respectively.The proposed GMLPG demonstrated a great potential for being employed as a sensor for biomedical and biochemical applications.

Chondroitin sulfate-mediated albumin corona nanoparticles for the treatment of breast cancer

Chondroitin sulfate-mediated albumin corona nanoparticles were readily prepared without any chemical reaction,and their active tumor targeting and therapeutic effects were examined.Negatively charged chondroitin sulfate(CS)and positively charged doxorubicin(DOX)self-assembled into nanoparticles(CS-DOX-NPs)via electrostatic interactions.Bovine serum albumin(BSA)was then adsorbed on the surface of CS-DOX-NPs to form albumin corona nanoparticles(BC-DOX-NPs)protected from endogenous proteins.Due to the dual effect of BSA and CS,BC-DOX-NPs interacted with the gp60,SPARC and CD44 receptors on tumor cells,facilitating their rapid and efficient transcytosis and improving their accumulation and uptake within tumor tissues.The simultaneous presence of BSA and CS also allowed BC-DOX-NPs to target CD44 efficiently,leading to greater cellular uptake and cytotoxicity against 4 T1 cells than CS-DOX-NPs or free DOX.Intravenous injection of BCDOX-NPs into orthotopic 4 T1 tumor-bearing mice led to greater drug accumulation at the tumor site than with CS-DOX-NPs or free DOX,resulting in significant inhibition of tumor growth and lower exposure of major organs to the drug.

Effects of proteins on magnesium degradation-static vs.dynamic conditions

The interaction between organic molecules and biomaterial surfaces determines the fate of biomaterials during their service life,which is also the research hotspots in the field of biomaterials.To understand the mechanism of protein interaction with magnesium(Mg)degradation,alloying elements,immersion time,protein concentration and surface conditions have been previously considered for the effect of proteins on Mg degradation.However,fluid flow,as one of the critical factors,drew little attention in this case.In the present study,the effect of bovine serum albumin(BSA)and fetal bovine serum(FBS)on Mg degradation was compared under static and dynamic conditions.The results revealed that both BSA and FBS slightly decreased the degradation rate of Mg in Hanks’balanced salt solution(HBSS)under static immersion due to the protein adsorption and the formation of a Ca/P-rich top layer on Mg surface,whereas under dynamic flow condition the degradation of Mg was significantly accelerated in the presence of BSA or FBS.The reasons seemed to stem from the weakened protein adsorption on Mg surface in this case and the dynamically enhanced interaction between proteins and ions/products in solutions,which largely weaken the combination of the top Ca/P-rich layer with the inner corrosion product layer.These results highlight the importance of testing conditions for Mg characterization in vitro and the synergistic effect between different parameters on Mg degradation.

Label-free colorimetric estimation of proteins using nanoparticles of silver

Metallic nanoparticles have received considerable attention in bioassays and diagnostics due to their unique surface plasmon resonance(SPR) properties.Gold nanoparticles have been employed for the development of SPR-based colorimetric bioassays.In the present report we have described a sensitive colorimetric approach for estimation of proteins,within a detection limit of 10?80 μg/m L,using unmodified silver nanoparticles.Besides the common advantages of colorimetric assay such as simplicity,high sensitivity,and low cost,our method has a label-free design and provides an important and attractive alternative to classical sensing probes and systems.The present work will contribute to the development of nanotechnology-based diagnostic tools.

3-[2-(5-溴-噻吩基)]-1-苯基-2-丙烯酮与牛血清白蛋白的相互作用

通过苯乙酮和5-溴噻吩-2-甲醛合成了3-[2-(5-溴-噻吩基)]-1-苯基-2-丙烯酮(BTPPO)。使用光谱法和分子对接模拟研究了BTPPO与牛血清白蛋白(BSA,bovine serum albumin)的作用过程。同时,研究了金属离子(Cu^(2+),Co^(2+),Pb^(2+),Ag^(+),Hg^(2+),Cd^(2+))对BTPPO与BSA相互作用的影响。结果表明:BTPPO与BSA的作用主要是静态荧光淬灭过程,两者之间的结合以疏水和静电作用为主,结合常数(K_(a))为10^(4)左右。根据Forster理论,可以计算得BTPPO和BSA的共振能量转移距离小于7 nm。另外,在280 nm和295 nm激发波长下蛋白质的荧光淬灭实验表明:BTPPO与BSA的主要结合位点是BSA的亚结构域ⅡA(siteⅠ)。金属离子(Pb^(2+)除外)的存在可能会影响BTPPO荧光淬灭效果。分子对接模拟结果表明:BTPPO是通过疏水和极性作用嵌入BSA分子的亚结构域ⅡA(siteⅠ)的疏水腔内的。

A stability-indicating high performance liquid chromatography method to determine apocynin in nanoparticles

In this study, we developed and validated a fast, specific, sensitive, precise and stability-indicating high performance liquid chromatography(HPLC) method to determine the drug apocynin in bovine serum albumin(BSA) nanoparticles. Chromatographic analyses were performed on an RP C18 column and using a photodiode array detector at a wavelength of 276 nm. Mobile phase consisted of a mixture of acetonitrile and 1% acetic acid(60:40, v/v), and it was eluted isocratically at a flow rate of 0.8 mL/min. The retention time of apocynin chromatographic peak was 1.65 min. The method was linear, precise, accurate and specific in the range of 5–100 μg/mL. The intra-and inter-day precisions presented relative standard deviation(RSD) values lower than 2%. The method was robust regarding changes in mobile phase proportion, but not for flow rate. Limits of detection and quantitation were 78 ng/mL and 238 ng/mL, respectively. Apocynin was exposed to acid and alkali hydrolysis, oxidation and visible light. The drug suffered mild degradation under acid and oxidation conditions and great degradation under alkali conditions. Light exposure did not degrade the drug. The method was successfully applied to determine the encapsulation efficiency of apocynin in BSA nanoparticles.

Selective separation of protein and saccharides by ionic liquids aqueous two-phase systems

In the present work,it was found that aqueous solution of a hydrophilic ionic liquid (IL),1-butyl-3-methylimidazolium dicyanamide ([C4mim][N(CN)2]),could be separated into an aqueous two-phase system (ATPS) by inorganic salts such as K2HPO4 and K3PO4.The top phase is IL-rich,while the bottom phase is phosphate-rich.It was shown that 82.7%-100% bovine serum albumin (BSA) could be enriched into the top phase and almost quantitative saccharides (arabinose,glucose,sucrose,raffinose or dextran) were preferentially extracted into the bottom phase in a single-step extraction by [C4mim][N(CN)2] + K2HPO4 ATPS.The extraction efficiency of BSA from the aqueous saccharide solutions was influenced by the molecular structure of saccharides.The conductivity,dynamic light scattering (DLS) and transmission electron microscopy (TEM) were combined to investigate the microstructure of the IL-rich top phase and the possible mechanism for the selective separation.It is suggested that the formation of the IL aggregate and the IL aggregate-BSA complex plays a significant role in the separation of BSA from aqueous saccharide solutions.This is the first example for the selective separation by ILs-based ATPSs.It is expected that these findings would have potential applications in bio-analysis,separation,and IL recycle.

In-situ and one-step preparation of protein film in capillary column for open tubular capillary electrochromatography enantioseparation

In this wo rk,the phase-transitioned BSA(PTB)film using the mild and fast fabrication process adhered to the capillary inner wall uniformly,and the fabricated PTB film-coated capillary column was applied to realize open tubular capillary electrochromatography(OT-CEC)enantioseparation.The enantioseparation ability of PTB film-coated capillary was evaluated with eight pairs of chiral analytes including drugs and neurotransmitters,all achieving good resolution and symmetrical peak shape.For three consecutive runs,the relative standard deviations(RSD)of migration time for intra-day,inter-day,and column-tocolumn repeatability were in the range of 0.3%-3.5%,0.2%-4.9%and 2.1%-7.7%,respectively.Moreover,the PTB film-coated capillary column ran continuously over 300 times with high separation efficiency.Therefore,the coating method based on BSA self-assembly supramolecular film can be extended to the preparation of other proteinaceous capillary columns.

BSA-lysozyme coated NaCa_(2)HSi_(3)O_(9)nanorods on titanium for cytocompatibility and antibacterial activity

Extracellular supplement of Ca and Si accelerates osteogenisis and angiogenisis during bone repair.CaSi-based ceramics are biodegradable and can release Ca and Si ions efficiently.However,locally high alkalinity induced by excessively rapid degradation limits their application.In this paper,NaCa_(2)HSi_(3)O_(9)(NCS)nanorods were fabricated on Ti by micro-arc oxidation and hydrothermal treatment;protein layers consisted of different rations of bovine serum albumin(BSA)and lysozyme(LYS)were prepared on NCS nanorods by spinning coating and thermal stabilization.The microstructure,ion releasing and wettability of coatings were observed;osteoblast and endotheliocyte behaviors,as well as bacteria response in vitro,were evaluated.The protein layer did not change microstructure and phase composition of nanorods but acted as a barrier isolating nanorods from contacting medium,and it results in slowing down the degradation of nanorods.The reduced increase of pH value,released Ca and Si ions and incorporation of LYS in BSA protein layer gave NCS nanorods improved MC3 T3-E1 and HUVECs response,compared with Ti.Meanwhile,the protein layers except pure LYS endowed nanorods with a highly antibacterial effect against staphylococcus aureus and escherichia coli simultaneously,indicating the key role of BSA in resisting antibacterial adhesion.NCS nanorods with BSA and LYS composited protein layers should be a potential coating applied on Ti implants for increasing osseointegration.