Cu~(2+)、Zn~(2+)和Pb~(2+)对绿原酸与牛血清白蛋白结合作用的影响

以杜仲绿原酸(CA)为原料,在模拟人体生理条件下,采用荧光光谱和紫外吸收光谱等方法,考察Cu2+、Zn2+和Pb2+对CA与牛血清白蛋白(BSA)相互作用产生的影响。结果表明,金属离子的存在不会改变CA对BSA的猝灭类型,但对其猝灭速率常数(kq)、结合常数(K)以及结合位点(n)会有不同程度的影响;CA与BSA之间的反应属于自发型,主要以范德华力和氢键为主,Zn2+和Pb2+的存在不会改变其作用力类型,Cu2+则会使作用力变为以静电吸引力为主;Zn2+和Pb2+会将供体与受体之间的结合距离分别减小1.975%和14.07%,Cu2+的干扰使CA与BSA之间的结合距离增大11.58%;同步荧光光谱显示CA与BSA中的酪氨酸残基和色氨酸残基都有相互作用,三维荧光测定结果进一步表明猝灭剂对BSA构象及微环境会引起变化。     

Graphene oxide-based SPR biosensor chip for immunoassay applications

This work develops a highly sensitive immunoassay sensor for use in graphene oxide sheet (GOS)-based surface plasmon resonance (SPR) chips. This sensing film, which is formed by chemically modifying a GOS surface, has covalent bonds that strongly interact with the bovine serum albumin (BSA), explaining why it has a higher sensitivity. This GOS film-based SPR chip has a BSA concentration detection limit that is 100 times higher than that of the conventional Au-film-based sensor. The affinity constants (K_A) on the GOS film-based SPR chip and the conventional SPR chip for 100 μg/ml BSA are 80.82 × 10⁶ M^-1 and 15.67 × 10⁶ M^-1, respectively. Therefore, the affinity constant of the GOS film-based SPR chip is 5.2 times higher than that of the conventional chip. With respect to the protein-protein interaction, the SPR sensor capability to detect angle changes at a low concentration anti-BSA of 75.75 nM on the GOS film-based SPR chip and the conventional SPR chip is 36.1867 and 26.1759 mdeg, respectively. At a high concentration, anti-BSA of 378.78 nM on the GOS film-based SPR chip and the conventional SPR chip reveals two times increases in the SPR angle shift. Above results demonstrate that the GOS film is promising for highly sensitive clinical diagnostic applications.     

青海西宁汉、藏族代谢综合征高血清尿酸水平影响因素分析

目的：探讨青海西宁地区汉、藏族代谢综合征（MS）患者高血清尿酸（SUA）水平的影响因素。方法将335例 MS 患者根据 SUA 水平与种族不同分为4组：汉族 MS 伴正常 SUA 组（A 组）98例、汉族 MS 伴高 SUA 组（B 组）111例、藏族 MS 伴正常 SUA 组（C 组）64例及藏族 MS 伴高 SUA 组（D 组）62例。收集患者的一般资料,包括：年龄、身高、体质量及体质量指数（BMI）;并采集静脉血行相关生化指标检测,包括空腹血糖（FBG）、总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）、载脂蛋白 AI（apo AI）、载脂蛋白 B（apo B）、尿酸（UA）、超敏 C 反应蛋白（hs-CRP）及白细胞介素-6（IL-6）。结果B 组的年龄、BMI、FBG、TC、TG、LDL-C、apo AI、apo B、hs-CRP 及 IL-6均较 A 组显著增加（P ＜0．05）,D 组的年龄、BMI、FBG、TC、TG、LDL-C、apo AI、apo B、hs-CRP 及 IL-6均较 C 组显著增加（P ＜0．05）;B 组与 D 组的 BMI、FBG、TC、TG、LDL-C、apo B、hs-CRP 及 IL-6相比差异均有统计学意义（P ＜0．05）。Logistic 回归分析结果显示,汉族 MS 患者高 SUA 的影响因素有：BMI、FBG、TC、TG、LDL-C、apoB、hs-CRP 及 IL-6,藏族 MS 患者高 SUA 的影响因素有：年龄、BMI、FBG、TC、TG、LDL-C、apoB、hs-CRP 及 IL-6。结论青海西宁地区汉、藏族 MS 患者高 SUA 水平与 BMI、FBG、TC、hs-CRP 及 IL-6相关;藏族人群在 MS 的预防过程中应该更注重 SUA 水平的控制。     

荧光光谱法研究头孢孟多脂与牛血清白蛋白的相互作用

模拟生理条件下,用荧光光谱法和紫外-可见吸收光谱法研究头孢孟多酯和牛血清白蛋白(BSA)结合反应的特征。研究表明:头孢孟多酯与BSA形成复合物,从而猝灭BSA的内源性荧光,该过程为静态猝灭过程。根据SternVolmer方程得出不同温度下结合位点数n和结合常数Ka;结合位点位于BSA的亚结构IIA中。通过计算相应的热力学参数,确定头孢孟多酯与BSA之间的作用力主要为静电作用力。利用同步荧光光谱探讨了头孢孟多酯与BSA作用前后白蛋白的构型变化。Hill系数nH1,表明头孢孟多酯有弱的负协同作用。此研究不仅对于揭示体内药物动力学问题和指导临床合理用药具有一定意义,而且对药物分子设计及新药开发等也具有重要指导意义。     

Kitchen Chemistry 101: Multigram Production of High Quality Biographene in a Blender with Edible Proteins

A high yielding aqueous phase exfoliation of graphite to high quality graphene using edible proteins and kitchen chemistry is reported here. Bovine serum albumin (BSA), β‐lactoglobulin, ovalbumin, lysozyme, and hemoglobin are used to exfoliate graphite and the exfoliation efficiency depended on the sign and magnitude of the protein charge. BSA showed maximum exfoliation rate, facilitated graphite exfoliation in water, at room temperature, by turbulence/shear force generated in a kitchen blender at exfoliation efficiencies exceeding 4 mg mL^?1 h^?1. Raman spectroscopy and transmission electron microscopy indicated 3–5 layer, defect‐free graphene of 0.5 μm size. Graphene dispersions loaded on a cellulose paper (650 μg cm^?2) showed the film conductivity of 32 000 S m^?1, which is much higher than graphene/polymer composites. Our method yielded ≈7 mg mL^?1, BSA‐coated graphene with controllable surface charge, which is stable under wide ranges of pH (3.0–11) and temperature (5.0–50 °C), and in fetal bovine serum, for more than two months.These findings may lead to the large scale production of graphene for biological applications.     

Prediction of calcium concentration in human blood serum using an artificial neural network

A predictive method, based on artificial neural network (ANN) has been developed to study absorbance and pH effects on the equilibrium of blood serum. This strategy has been used to analyze serum samples and to predict the calcium concentration in blood serum. A dedicated data acquisition system is designed and fabricated using a LPC2106 microcontroller with light emitting diode (LED) as source and photodiode as sensor to measure absorbance and to calculate the calcium concentration. A multilayer neural network with back propagation (BP) training algorithm is used to simulate different concentration of calcium (Ca²⁺) as a function of absorbance and pH, to correlate and predict calcium concentration. The computed calcium concentration by neural network is quite satisfactory with correlations R² = 0.998 and 0.995, standard errors of 0.0127 and 0.0122 in validation and testing stages respectively. Statistical analysis are carried out to check the accuracy and precision of the proposed ANN model and validation of results produce a relative error of about 3%. These results suggest that ANN can be efficiently applied and is in good agreement with values obtained with the current clinical spectrophotometric methods. Hence, ANN can be used as a complementary tool for studying metal ion complexion, with special attention to the blood serum analysis.     

Determination of trace bismuth in human serum by cloud point extraction coupled flow injection inductively coupled plasma optical emission spectrometry

A cloud point extraction method for the preconcentration of ultra-trace bismuth in human serum prior to its determination by inductively coupled plasma optical emission spectrometry had been developed in this paper. The cloud point extraction method was based on the complex of Bi(III) with 8-hydroxyquinoline and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time were investigated in detail. An enrichment factor of 81 was obtained for the preconcentration of Bi(III) with 25 mL solution. Under the optimal conditions, the detection limit of Bi(III) is 0.12 μg L⁻¹. The relative standard deviation (n = 7) of determination was 2.3%, values of recovery of bismuth were from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination trace bismuth in human serum.     

TiO2纳米管表面蛋白质-羟基磷灰石复合涂层及其结合强度

采用阳极氧化法在钛表面制备不同管径的TiO2纳米管,450℃热处理后经牛血清白蛋白(BSA)与钙磷的共沉积得到载有BSA的羟基磷灰石(HA)涂层.经检测发现,170nm管径的TiO2表面比100和50nm管径的表面具备更好的矿化能力,HA的形成能力随管径的增大而提高.大管径表面得到的涂层结合强度高于小管径的,可达16.95MPa.经过真空预矿化的试样,涂层结合强度明显高于未经过预矿化的试样,且HA涂层生长速率加快.BSA与磷酸钙在真空预矿化后共沉积到氧化钛纳米管表面,短时期内形成BSA-HA涂层,是在钛基生物材料表面制备生物活性涂层的有效方法.     

肝硬化的血清荧光光谱诊断研究

本文采用 4 76 .5nm的氩离子激发光激发肝硬化患者及健康人血清样品的自体荧光 ,分析了 4 90 - 6 0 0nm范围内的荧光光谱 ,发现二者光谱的带宽和相对强度比I4 90 /I6 0 0存在明显差异 ,同时使用这两个参量对样品进行分析时 ,与病理结果相比较得到了 76 .5 %的总符合率 ,该结果对肝硬化的光谱诊断有一定的参考价值