BSA和FN在纳米化钛表面的蛋白吸附及释放行为

通过阳极氧化技术, 在钛表面制备一层管径为100nm左右的氧化钛纳米管. 选取小牛血清白蛋白(BSA)和纤维连接蛋白(FN)两种蛋白质进行蛋白吸附实验, 并在仿生条件下进行蛋白质的体外释放. 对吸附了蛋白的纳米管试样表面进行红外和荧光定性分析, 同时采用考马斯亮蓝法对纳米管表面的蛋白吸附进行定量检测, 实验发现纳米管试样更有利于蛋白质的吸附, 且FN在试样表面吸附时的吸附率大于BSA. 氧化钛纳米管的蛋白释放分为突释和缓释两个阶段, 其释放机制符合Fickian扩散.     

两性离子聚合物表面改性的聚偏氟乙烯抗污染膜的制备及性能

提高聚偏氟乙烯(PVDF)抗污染性能是改善PVDF应用效果的重要途径。文中通过自由基聚合的方法将抗污染材料——两性离子类化合物磺酸甜菜碱(DMAPS)接枝到碱处理过的PVDF膜表面。研究了接枝DMAPS后,PVDF膜表面的结构与性能变化,并初步探讨了改性后的PVDF膜对牛血清蛋白的吸附性能。结果表明,在PVDF膜表面接枝DMAPS后,膜表面孔洞减小,亲水性提高。虽然改性后的PVDF膜通量有所下降,但通过牛血清蛋白(BSA)的振荡吸附实验发现,两性离子改性膜表现出良好的抗蛋白质吸附性能。与PVDF原膜相比,改性膜在BSA溶液中通量下降率小,用水清洗后膜通量恢复率高。     

两性离子聚合物功能化改性PVDF膜及其性能研究

通过活性自由基聚合用羧酸甜菜碱丙烯酸甲酯(CBMA)和苯乙烯(St)制备了一种含有两性离子的聚合物P(St_x-co-CBMA_y),并将其作为添加剂,采用非溶液致相分离(NIPS)法制备了改性聚偏氟乙烯(PVDF)膜,并对膜性能进行测试研究.通过ATR-FTIR及XPS分析可知,改性膜表面出现两性离子聚合物的富集.两性离子的加入对膜的微观结构有明显影响,改性膜的孔隙率及膜厚明显增加.两性离子聚合物的加入改变了膜表面电荷分布,膜的等电点升高,对膜的抗污染性能具有一定的影响.改性膜在静态吸附条件下(pH=5.3)对1.0 g/L牛血清蛋白(BSA)和溶菌酶(LYZ)的吸附量明显降低,具有优异的抗污染性能.用改性膜对BSA和海藻酸钠(SA)进行动态过滤,结果表明,改性膜M-P1对BSA及SA的污染大部分为可逆污染,膜具有较高的通量恢复率.     

利用胶原-肝素自组装多层膜改善纯钛表面血液相容性的研究

为了改善钛表面的血液相容?用层层自组装技术将抗凝药物肝素和细胞外基质成分之一的胶原层层交替吸附到钛表面,形成多层薄膜,使具有良好的抗凝血功能.钛通过氢氧化钠处理表面带负电,在聚赖氨酸溶液中会吸附一层带正电的聚赖氨酸,然后将其交替浸泡于带负电的肝素和带正电的胶原中形成自组装薄膜.通过傅立叶红外漫反射(FTIR)检测材料表面基团的变化,通过测水接触角的方法跟踪组装过程,通过扫描电子显微镜(SEM)观察材料表面形貌的变化.血小板黏附实验显示钛改性后表面血小板黏附量明显减少,且反映血小板激活程度的P-selectin的表达量结果也显示,钛改性后表面血小板激活程度显著降低,活化部分凝血活酶时间(APTT)和外源性凝血系统的凝血酶原时间(PT)的实验显示钛改性后表面凝血时间延长,血液相容性得到改善.研究说明这种方法对于心血管材料钛的改性有重要价值.     

甲氧基聚氧化乙烯丙基三甲氧基硅烷改性硅片表面的蛋白质吸附行为

以甲氧基聚氧化乙烯丙基三甲氧基硅烷对硅片表面进行改性,使其表面具有良好的亲水性能.用考马斯亮蓝法考察了硅片在不同浸泡时间和不同蛋白质初始溶液浓度下,牛血清白蛋白(BSA)在硅片表面的吸附行为.研究发现,蛋白质吸附是一个动态过程,符合Langmuir理论吸附模型,浸泡120min后,吸附和解吸附达到动态平衡.当蛋白质初始...     

携载蛋白质的氧化钛纳米管表面成骨细胞行为

通过阳极氧化技术,在光滑钛表面制备一层管径约100nm的纳米管,并选用小牛血清白蛋白（BSA）和纤维连接蛋白（FN）以及两种蛋白的混合溶液（BF）进行蛋白吸附试验。将吸附蛋白后的试样进行细胞培养,所用细胞为MC-3T3E1成骨细胞株,结果表明,较光滑钛吸附蛋白前后的纳米管试样显示出更好的成骨活性,同时,吸附单组分纤维连接蛋白的纳米管试样能更好地促进成骨细胞的黏附和生长,具有更高的生物活性。     

聚丙烯微孔膜的表面改性和抗污染性

用化学方法在聚丙烯微孔膜表面上接枝丙烯酰胺。利用红外光谱,X射线光电子能谱,扫描电镜,原子力显微镜观察了膜表面形态和微观结构的变化,同时考察了膜的接触角和吸水能力,对BSA蛋白质的吸附量及水通量和抗污染能力。结果表明,随着接枝率的提高,接触角从95°减小到38°,吸水率也提高到163.9%。改性后,PP膜对BSA的吸附减少,膜的水通量减小,但同时膜的污染率下降,当接枝率为11.5%时,膜的污染率为0.274,比接枝前下降了55%。改性后PP微孔膜的亲水性和抗污染能力得到较大提高。     

Ti合金表面沉积羟基磷灰石-牛血清蛋白生物活性涂层

通过仿生生长方法,将预处理后的钛片浸入到添加有牛血清蛋白的模拟体液中,使钙磷盐和牛血清蛋白(BSA)共沉积到钛合金的表面,制备生物活性涂层.利用SEM、XRD、红外光谱等对涂层进行了表征,结果表明:BSA通过化学作用和钙磷盐共沉积到基体的表面,并且BSA具有细化涂层晶粒的作用.     

基于自组装法聚合吡咯的制备及对蛋白质的吸附

制备了一种新型应用于生物芯片的导电聚合物敏感膜,研究了蛋白质在导电聚合物敏感膜表面上的吸附机理。首先合成巯基修饰的吡咯单体,然后通过自组装在金膜表面制备N-巯基吡咯自组装膜,并通过化学法制备聚合吡咯膜,详细考察了牛血清白蛋白(BSA)在敏感膜上的吸附行为。用傅立叶红外光谱(FT-IR)和X射线光电子能谱(XPS)考察了自组装膜及聚合吡咯膜的化学结构。用表面等离子谐振仪考察了BSA在自组装膜和聚合吡咯膜上的吸附行为,以及聚合时间、缓冲液pH值对BSA吸附的影响。     

超细氧化铝粉体的表面改性研究

利用两种硅烷偶联剂、三种钛酸酯偶联剂对Al2O3粉体颗粒表面有机改性,比较了不同偶联剂对颗粒表面的改性效果,结果表明硅烷偶联剂未能对粉体表面进行有效的有机改性.红外光谱分析证实了偶联剂NTC401在Al2O3粉体表面进行了化学吸附,而偶联剂JSC和CT136在Al2O3粉体表面主要发生物理吸附.电镜照片说明,经NTC401改性的Al2O3粉体粒子之间的团聚得到了有效改善,而经JSC和CT136改性的Al2O3粉体粒子之间的团聚未得到改善.机理分析认为中心钛原子六配位的结构能够有效阻止颗粒团聚.     

Study on protein conformation and adsorption behaviors in nanodiamond particle-protein complexes

In the present research, the conformation of bovine serum albumin (BSA) in the nanodiamond particle (ND)-BSA complex was studied by Fourier transform infrared spectroscopy, fluorescence spectroscopy, UV-vis spectroscopy, and circular dichroism spectroscopy. The spectroscopic study revealed that most BSA structural features could be preserved in the complex though the BSA underwent conformational changes in the complex due to ND-BSA interaction. In addition, BSA adsorption isotherms and zeta-potential measurements were employed to investigate the pH dependence of the ND-BSA interaction. The changes in surface charge of the ND-BSA complex with pH variations indicated that the binding of BSA to ND might lead to not only the adsorption of BSA onto the ND surface but also the partial breakup of ND aggregates into relatively small ND-BSA aggregates because of the strong binding force between ND and BSA. The results show that ND is an excellent platform for protein immobilization with high affinity and holds great potential to be used for biosensor applications.     

Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by ¹³C and ²⁹Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.     

In situ comparative studies of self-assembly adsorption of bovine serum albumin on nano films by atomic force microscopy

The self-assembly adsorption of function protein on crystal surfaces, as a common phenomenon, broadly takes place in many applications of biosensors, biocapsules and bioMEMS/bioNEMS. To systematically investigate the different adsorption characteristic of the same function protein on two different crystal surfaces under the identical environment, a hybrid surface composing silica and discontinuous Gold Nano Film (GNF) was fabricated by Physical Vapor Deposition (PVD) and ultrasonic cleaning method, where the dynamic process of the self-assembly adsorption of Bovine Serum Albumin (BSA) was in situ observed by Atomic Force Microscope (AFM). The variations on the junction area of the two different surfaces were studied in the aqueous solution before and after injecting BSA with 0.05 mg/ml concentration. It was found that silica, compared with same hydrophilic GNF, took on a fairly weak adsorption force. The results indicated that the adsorption strength of BSA on the hydrophilic crystal surface was determined not only by hydrophilic property, but also other interaction forces, like Van der Waals and so on. Moreover, observed under the contact mode of AFM, BSA adsorbed on GNF had great tendency to forming a ridge-like topography. These results may be helpful in the application of immunosensors and other areas.     

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-3Cu alloy were studied in a phosphate-buffered saline solution containing 0,1,3,and 6 g L-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 cor-rosion 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 (Q～s) 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 TiO2 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-3Cu alloy.     

The interaction of the polyphenylacetylene surface with biological environments studied by XPS, RAIRS and biological tests

A π-conjugated polymer, polyphenylacetylene or PPA, has been tested for its possible applications as biosensor or biomaterial. Protein adsorption was investigated by incubating PPA films in solutions of bovine serum albumin (BSA) dissolved in phosphate buffer (PBS) having increasing protein concentration. Investigations on the PPA films were carried out by means of two surface analysis techniques, X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy (RAIRS). Desorption of BSA from the PPA surface was also investigated. Finally, the cytototoxicity of the PPA surface was checked by measuring viability and proliferation of lymphoma macrophages and SAOS osteoblasts grown in the presence of the polymer.     

Probing Albumin Adsorption onto Calcium Phosphates by XPS and ToF-SIMS

In this study the binding and assembly of bovine serum albumin (BSA) onto three different calcium phosphate phases (hydroxyapatite, dibasic calcium phosphate dihydrate, and β-tricalcium phosphate) was investigated using a combination of X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). XPS was used to record adsorption isotherms and to quantify the amount of BSA adsorbed onto the different CaP surfaces. On all three surfaces a monolayer of adsorbed BSA was formed. ToF-SIMS was then used to investigate how the structure of BSA changes upon surface binding. ToF-SIMS data from BSA films on the three CaP surfaces showed intensity differences of secondary ions originating from both hydrophobic and hydrophilic amino acids. For a more quantitative examination of structural changes, we developed a ratio comparing the sum of intensities of secondary ions from hydrophobic and hydrophilic residues. A small, but statistically significant, increase in the value of this ratio (7%) was observed between a BSA film on hydroxyapatite versus dibasic calcium phosphate dihydrate. From this ratio we can make some initial hypotheses about what specific changes in BSA structure relate to these differences observed in the ToF-SIMS data.     

Protein adsorption on citrate modified magnetic nanoparticles

Magnetic iron oxide nanoparticles were prepared by chemical co-precipitation method and then modified with sodium citrate. These iron oxide nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffractometer (XRD), and vibrating sample magnetometer (VSM). BSA was adsorbed on these citrate modified nanoparticles using two types of buffers (acetate buffer, pH 4.0, 4.7 and phosphate buffer, pH 7.4). The results showed that the maximum adsorption of BSA was 83 mg/g at its isoelectric point (pH 4.7). Fourier-transform infrared spectroscopy (FTIR) was used to confirm the attachment of citrate groups and BSA on the prepared magnetic nanoparticles. BSA was desorbed from nanoparticles under alkaline conditions, which was confirmed by SDS-PAGE electrophoresis, UV-vis and fluorescence spectra. The desorbed BSA showed small changes in its structure. The adsorption results indicated that BSA adsorption on citrate modified iron oxide nanoparticles occurred mainly by electrostatic mechanism.     

Nanogel surface coatings for improved single-molecule imaging substrates

Surfaces that resist protein adsorption are important for many bioanalytical applications. Bovine serum albumin (BSA) coatings and multi-arm poly(ethylene glycol) (PEG) coatings display low levels of non-specific protein adsorption and have enabled highly quantitative single-molecule (SM) protein studies. Recently, a method was developed for coating a glass with PEG–BSA nanogels, a promising hybrid of these two low-background coatings. We characterized the nanogel coating to determine its suitability for SM protein experiments. SM adsorption counting revealed that nanogel-coated surfaces exhibit lower protein adsorption than covalently coupled BSA surfaces and monolayers of multi-arm PEG, so this surface displays one of the lowest degrees of protein adsorption yet observed. Additionally, the nanogel coating was resistant to DNA adsorption, underscoring the utility of the coating across a variety of SM experiments. The nanogel coating was found to be compatible with surfactants, whereas the BSA coating was not. Finally, applying the coating to a real-world study, we found that single ligand molecules could be tethered to this surface and detected with high sensitivity and specificity by a digital immunoassay. These results suggest that PEG–BSA nanogel coatings will be highly useful for the SM analysis of proteins.     

Determination of adsorbed protein concentration in aluminum hydroxide suspensions by near-infrared transmittance spectroscopy

Analysis of aluminum hydroxide based vaccines is difficult after antigen adsorption. Adsorbed protein is often assessed by measuring residual unadsorbed protein for quality control. A new method for the direct determination of adsorbed protein concentration in suspension using near-infrared (NIR) transmittance spectroscopy is proposed here. A simple adsorption system using albumin from bovine serum (BSA) and aluminum hydroxide as a model system is employed. The results show that the NIR absorbance at 700-1300 nm is correlated to the adsorbed BSA concentration, measured by the ultraviolet (UV) method, using the partial least square regression (PLSR) method to construct a calibration model. The linear concentration range of adsorbed BSA is from 0 to 1.75 mg/mL by using 10 mm path length cuvettes. The influence of the sedimentation in suspension, different buffers, and different aluminum hydroxide batches was investigated in this study. It shows that the batch variation is the main influence factor of this method, while the buffer variation has no influence. However, the pretreatment of spectral data by subtracting spectra of BSA blank control (aluminum hydroxide without BSA) can significantly reduce the batch influence, and the NIR predicted results show good agreement with the reference values. The NIR method might be the only direct method for the determination of adsorbed protein concentration in suspension so far. It is a nondestructive method, and it has great advantage for use in vaccine production as a method for quality control and quality assurance.