牛血清蛋白-Au配合物及其复合物制备及表征

以牛血清蛋白(bovine serum albumin,BSA)、氯金酸(HAuCl4)、NaOH等为原料,采用一锅合成法制备了牛血清蛋白-Au配合物(BSA-Au),观察到了样品的宽带红光荧光发射。通过库仑力作用将BSA-Au与表面带有正电荷的金纳米颗粒进行复合,对纳米复合物的吸收光谱及荧光光谱特性进行了研究。实验结果表明,在本实验条件下,金纳米颗粒虽然增强了复合物样品在可见光区域的光吸收,但对BSA-Au红光发光有猝灭作用。     

牛血清白蛋白单克隆抗体的筛选与双抗体夹心ELISA检测方法的建立

目的筛选高效抗牛血清白蛋白(BSA)单克隆抗体细胞株,并建立BSA抗原检测的双抗体夹心ELISA法。方法分别采用辛酸-硫酸铵法和葡萄球菌A蛋白亲和层析法纯化单抗,并进行抗体类型、腹水效价、特异性和相对亲和力测定;应用纯化的单抗建立BSA双抗体夹心ELISA检测法,并进行初步应用。结果筛选出4株可稳定分泌抗BSA单抗的杂交瘤细胞株,抗体类型为IgG,抗体滴度均可达10-6,特异性良好,相对亲和力较高。建立的双抗体夹心ELISA法线性范围为1.25～20ng/ml,R2>0.98,灵敏度为1.25ng/ml。结论已筛选出高效抗BSA的单抗,并建立了BSA双抗体夹心ELISA检测方法。     

Macromolecularly imprinted calcium phosphate/alginate hybrid polymer microspheres with the surface imprinting of bovine serum albumin in inverse‐phase suspension

Macromolecularly imprinted calcium phosphate/alginate hybrid polymer microspheres surface imprinted with bovine serum albumin were prepared in inverse‐phase suspension by introducing the intermixture solutions of bovine serum albumin (BSA) and CaCl₂ in sodium alginate aqueous solution where (NH₄)₂HPO₄ was added beforehand. Morphology of the imprinted microspheres was observed by optical microscopy. Rebinding dynamic and thermodynamic behaviors of surface molecularly imprinted calcium phosphate/alginate polymer microspheres (CP/A SMIPMs) and embedding molecularly imprinted calcium phosphate/alginate polymer microspheres (CP/A EMIPMs) were evaluated. CP/A SMIPMs exhibited significant improvement in equilibrium rebinding capacity (Q_e) and imprinting efficiency (IE), compared to CP/A EMIPMs. The surface of CP/A SMIPMs was more competent to facilitate the migration and re‐assembling of proteins. Surface specific peak and interior specific peak were proposed to describe the characteristics of surface and interior specific rebinding behaviors in rebinding dynamics. The effects of (NH₄)₂HPO₄ addition were investigated in detail, along with the concentration of sodium alginate and CaCl₂ solutions to the rebinding and imprinting property of imprinted microspheres. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Quantification of the complexation of protein with neutral water borne polymer by fluorescence spectroscopy

The complexation of bovine serum albumin (BSA) with poly(N-isopropylacrylamide) (PNIPAM) in an aqueous system (pH 7) has been investigated by means of fluorescence spectroscopy. Through analyzing the change of fluorescence intensity of protein chromophores caused by complexation, a quantitative mathematical equation has been established and the average number of bound proteins per neutral polymer (n_b) can be calculated accurately without destroying the dynamic equilibrium of aqueous complex system. At the same time, with the help of this equation, the extreme value of n_b can also be calculated when PNIPAM concentration is low enough. Compared with traditional calculation methods, this method has the advantages of rapid detectability, high sensitivity, accuracy and extensive applicability. Thus, it is a better way to study the complexation of protein with polymer.     

血清降钙素原在细菌性脑膜炎中的价值

细菌性脑膜炎（BM）是儿童常见的中枢神经系统（CNS）疾病,对患儿健康具有严重威胁,及时对脑炎类型作出诊断并迅速启动治疗至关重要。目前诊断BM的金标准仍为脑脊液检查,但患儿配合度低,提取脑脊液操作难度和损失较大,且脑脊液培养耗时长、检测阳性率低,所以脑脊液检查对BM早期治疗的指导意义有限,存在延误病情的可能。血清降钙素原(S-PCT)对细菌感染早期预测有较高的敏感度和特异度。大量的证据表明S-PCT是评估已知或疑似CNS感染患者的有用工具,可以帮助诊断BM并评估预后。本文对目前关于S-PCT及其对BM的诊断和评估预后的价值等知识进行简要综述。     

Few layered graphene oxide thin films: A potential matrix for immunosensors

ABSTRACT

We have synthesized highly exfoliated graphene oxide (GO) and used it for the fabrication of electrochemical immunosensor. The thin films of GO were spin coated onto ITO/glass substrate and thereafter Bovine Serum Albumin (BSA) antibodies (Ab) were immobilized using EDC-NHS binding chemistry to design immunobioelectrode. The graphene oxide films were characterized using different spectroscopic techniques viz FT-IR, UV-Vis spectroscopy and HRTEM. The electrochemical activity of designed immunoelectrodes was studied by cyclic voltammetry (CV) that revealed a quasi reversible behaviour of graphene oxide films. The differential pulse voltammetry (DPV) measurements of the fabricated immunoelectrodes showed successful detection of analyte at very low concentration ranges (50 fg/mL–100 ng/mL). The present study entails the potential of GO for the development of various immunosensors for different diseases.     

利用AuNCs@GSH-CAP体系荧光增强检测BSA的研究

蛋白质的研究是当下的热点,目前已经涉及到了生物、医学、食品等各个领域,而纳米技术的发展极大程度上促进了对蛋白质的研究。简便、高灵敏、高选择性的检测方法是实现重大疾病早期诊断和治疗的关键,也是目前市场潜力巨大的方向。但是许多检测方法的荧光探针合成较为复杂以及成本高,且需要使用有毒性的有机试剂。本文中,我们采用氯霉素（CAP）荧光猝灭的金纳米簇（AuNCs@GSH）体系作为探针,通过体系荧光增强效应来检测牛血清白蛋白（BSA）。BSA可以增强AuNCs@GSH-CAP体系荧光强度,在一定浓度范围内体系荧光增强与BSA的浓度呈正相关。该方法具有较好的选择性和抗干扰性,且荧光效果明显,实现了在10~160μmol/L内具有良好的线性关系,其检测限为0.1μmol/L,对于蛋白质的快速检测有良好的发展前景。     

聚合物／盐系统中BSA分配系数的测定和关联

测定了２５℃时牛血清清蛋白在不同分子量的聚乙二醇／无机盐双水相系统中的分配系数。用改进的Ｄｉａｍｏｎｄ－Ｈｓｕ模型关联了ＢＳＡ在上述双水相系统中的分配系数,结果表明,对Ｄｉａｍｏｎｄ－Ｈｓｕ模型的改进是有效的,并联结果与实验值符合良好。     

分子对接技术与光谱法分析薯蓣皂苷和人血清白蛋白的相互作用

研究探讨了薯蓣皂苷（DS）对人血清白蛋白（HSA）的作用机制。运用dock 6.0分子对接法、荧光发射光谱法和紫外分光光度法,对DS同人体HSA之间的关系展开分析。DS与HSA之间有8种结合方式,再结合Grid打分值和Internal energy水平,选择第8种优势构象,Grid分数为-75.9787 kcal/mol,作用力为疏水作用,结合的氨基酸残基主要是色氨酸Trp214。荧光光谱显示DS浓度增大,HSA-DS荧光强度降低且波长蓝移,表示在DS作用下,HSA所含色氨酸（Trp）的荧光强度出现猝灭现象。波长差Δλ=15 nm和Δλ=60 nm条件下测定的同步荧光现象说明两者结合后,HSA所含Trp残基的附近环境随即出现了变化。根据Stern-Volmer方程计算得出双分子碰撞常数Kq均大于2.0×1010 L/mol?s和静态猝灭结合常数Ka均大于5×104 L/mol,证实猝灭机制属于疏水作用影响的静态猝灭,结合位点为1,与分子对接结果一致。紫外吸收图谱显示DS浓度增加,吸光度升高,进一步阐明彼此发生了作用。分子对接及光谱表明两者主要在色氨酸Trp214位置处通过疏水作用结合,HSA构象和微环境产生变化。从研究中获得的数据能够阐明薯蓣皂苷对HSA的作用机制,为进一步理解薯蓣皂苷在人体的贮藏运输过程中对蛋白质功能的影响提供新依据。     

黑米多酚对四氧嘧啶诱导糖尿病小鼠的影响

目的研究黑米多酚对四氧嘧啶诱导的糖尿病模型小鼠的降血糖作用。方法以黑米为原料提取纯化黑米多酚,在应用四氧嘧啶腹腔注射并成功建立高血糖模型小鼠方法的基础上,将模型组50只雄性小鼠按每组10只,随机分为阴性对照组(NM)、阳性对照组(PM)及黑米多酚低、中、高剂量组(B1、B2、B3)。另取10只雄性小鼠作为正常对照组(NC),连续灌喂4周。结果与正常组相比,模型组小鼠饮水、体重、血糖水平均有显著差异(P0.05),且血糖水平达到高血糖标准,说明造模成功;黑米多酚可以缓解四氧嘧啶造模糖尿病小鼠的症状,具体表现为减缓多饮、多尿、体重下降的症状;一定程度上减缓糖尿病小鼠血糖增高的趋势,且高剂量的黑米多酚可以显著降低糖尿病小鼠的血糖(P 0.05),有效刺激小鼠胰岛素的分泌和小鼠肝糖元的产生,对保护糖尿病小鼠的肝脏和肾脏具有一定的作用。结论黑米多酚具有降低四氧嘧啶诱导高血糖模型小鼠血糖的作用,但其机制有待进一步探究。