基于纳米多孔硅Bragg反射镜免标记生物传感器的研究

构建一种基于多孔硅Bragg反光镜的免标记的纳米生物传感器,通过在纳米多孔硅上固定的适配子的特异性识别能力,检测溶液中四环素浓度。当适配子结合不同浓度的四环素溶液时,引起多孔硅Bragg反光镜内部有效折射率的变化,反射谱峰位进而发生变化。传感器的有效检测范围为1~200μg/L,检测限为1μg/L。     

多孔硅Bragg反射镜适配子生物传感器检测心肌肌钙蛋白Ⅰ

通过脉冲腐蚀法制备多孔硅Bragg反射镜,将心肌肌钙蛋白Ⅰ(cTnⅠ)适配子共价固定到多孔硅Bragg反射镜的孔洞中,发现适配子能与cTnⅠ分子特异性结合.定量分析不同浓度的cTnⅠ与适配子结合后多孔硅Bragg反射镜的反射谱峰位的红移情况.结果表明:基于多孔硅Bragg反射镜适配子生物传感器的光学检测具有良好的特异性,且具有免标记及检测时间短等优异性能.传感器的线性检测范围0.05～4 nmol/L,最低检测限为0.05 nmol/L.     

适配子纳米生物传感器在青霉素检测中的应用

通过脉冲腐蚀法对硅片进行多孔硅的制备,利用玻片通过对共价法、离子吸附法和APTES修饰的戊二醛交联法3种固定适配子方法的对比,以确定较好的固定青霉素适配子的方法。将适配子固定在多孔硅上后,利用交流阻抗法对加入青霉素前后传感器阻抗值进行测定、对比,构建等效电路并进行阻抗拟合。对多孔硅传感器的Nyqu ist谱图进行分析以确定多孔硅表面成功固定了青霉素适配子,从而证明构建纳米生物传感器成功。传感器的线性检测范围为0.05~0.2 mg/L,检测限为0.05 mg/L。     

多孔硅Bragg反射镜适配子生物传感器检测心肌肌钙蛋白I

通过脉冲腐蚀法制备多孔硅Bragg反射镜,将心肌肌钙蛋白I（cTnI）适配子共价固定到多孔硅Bragg反射镜的孔洞中,发现适配子能与cTnI分子特异性结合。定量分析不同浓度的cTnI与适配子结合后多孔硅Bragg反射镜的反射谱峰位的红移情况。结果表明：基于多孔硅Bragg反射镜适配子生物传感器的光学检测具有良好的特异性,且具有免标记及检测时间短等优异性能。传感器的线性检测范围0．05-4nmol／L,最低检测限为0．05nmol／L。     

纳米多孔硅阻抗生物传感器的研究

构建了1种基于多孔硅材料,无需标记的纳米生物传感器,用于对牛血清白蛋白分子进行检测。通过对多孔硅进行表面处理,形成氧化膜,将抗体固定到多孔硅氧化层表面。在磷酸盐缓冲液中,通过电化学检测系统检测加入抗原后,传感器的阻抗值的变化。磷酸缓冲液（PBS）/抗体-氧化层/硅,构成电解液/绝缘层/半导体（electro-lyte-insulator-semiconductor,EIS）结构。传感器的线性检测范围为0.01～0.27mg/mL,检测限为0.01mg/mL。     

适配子生物传感器对青霉素的快速检测

将玻碳电极进行阳极氧化和氨基化修饰,通过碳二亚胺盐酸盐(EDC)、N-羟基丁二酰亚胺(NHS)活化作用将青霉素适配子结合在电极表面。该适配子电化学生物传感器分子识别能力强、无放射性标记、检测速率快,青霉素类的最佳检测范围是2.81~281 nmol/L,最低检测限为2.81 nmol/L,检测时间为5 m in。     

核酸适配体生物传感器对心肌肌钙蛋白Ⅰ的检测研究

核酸适配体生物传感器是利用固定在电极表面的适配子与被测溶液中心肌肌钙蛋白Ⅰ(cTnⅠ)发生特异性结合,从而达到检测的目的.我们对玻碳电极进行阳极氧化、氨基化修饰,通过碳二亚胺盐酸盐(carbodiimide hydrochloride,EDC)、N-羟基琥珀酰亚胺(N-hydroxysuccinimide,NHS)活化作用将适配子结合在电极表面.cTnⅠ最佳检测范围是0.05~5 nmol/L,最低检测限为0.05 nmol/L,检测时间为5 min.     

核酸适体生物传感器快速检测牛奶中抗生素

为了现场快速检测牛奶溶液中四环素类抗生素的含量,对电极进行阳极氧化、氨基化、活化等一系列处理,将四环素核酸适体作为识别分子,共价固定于玻碳电极表面,构建出新型核酸适体生物传感器。传感器可以特异性结合标本中四环素类抗生素,并产生电化学信号,强度与抗生素浓度相关。其最低检测量是1μg/L,检测时间为5 m in。     

免标记光学纳米生物传感器的研究

利用发光稳定的多孔硅,当蛋白质溶液固定到多孔硅表面时,其发光强度和反射光谱的峰位会随着被测物质量浓度的变化而发生变化的特性。制备免标记光学纳米生物传感器来检测牛血清白蛋白（BSA）,把不同质量浓度的BSA溶液固定到多孔硅上测量反射光谱的峰位和荧光强度的变化。实验结果表明：反射光谱的峰位与牛血清白蛋白的浓度呈线性关系：y=1．4189x＋366．31,R^2=0．9898;荧光强度的降低量与BSA溶液的浓度呈线性关系,检测限为8×10^-9 mol／L。     

分子印迹技术应用于血清中地高辛的快速检测

应用分子印迹的方法制备对地高辛有特异性吸附性能的印迹聚合物颗粒,再将颗粒与琼脂糖混合并固定于玻碳电极上制备成地高辛分子印迹聚合膜传感器,传感器可以特异性地结合模板分子地高辛且其电化学信号与模板浓度相关,再用它来检测血清中地高辛的含量。结果表明:分子印迹传感器具有制作简便、成本低、检测快速、特异性高、稳定性好等优点,检测下限为1.28 nmol/L,检测时间为5 min。     

Electrochemical aptasensor for tetracycline detection

An electrochemical aptasensor was developed for the detection of tetracycline using ssDNA aptamer that selectively binds to tetracycline as recognition element. The aptamer was highly selective for tetracycline which distinguishes minor structural changes on other tetracycline derivatives. The biotinylated ssDNA aptamer was immobilized on a streptavidin-modified screen-printed gold electrode, and the binding of tetracycline to aptamer was analyzed by cyclic voltammetry and square wave voltammetry. Our results showed that the minimum detection limit of this sensor was 10 nM to micromolar range. The aptasensor showed high selectivity for tetracycline over the other structurally related tetracycline derivatives (oxytetracycline and doxycycline) in a mixture. The aptasensor developed in this study can potentially be used for detection of tetracycline in pharmaceutical preparations, contaminated food products, and drinking water.     

Electrochemical detection of thrombin based on aptamer and ferrocenylhexanethiol loaded silica nanocapsules

A sensitive and specific electrochemical assay for detection of thrombin based on aptamer and ferrocenylhexanethiol loaded silica nanocapsules (FcSH/SiNCs) amplification is described. In the protocol, a double aptamer sandwich structure was formed in the presence of thrombin, in which an aptamer-labeled FcSH/SiNCs for electrochemical detection, and a streptavidin-coated magnetic bead immobilized aptamer for rapid and specific separation of target protein. After separated from the sample mixture under a magnetic field, the sandwich complex was treated with NaOH to release the loaded ferrocenylhexanethiol (FcSH) from the silica nanocapsules (SiNCs). Differential pulse voltammetry (DPV) was employed to detect the released FcSH, which was related to the concentration of the thrombin. The method took advantage of sandwich binding of two affinity aptamers for increased specificity, high payload of FcSH in SiNCs for signal amplification, magnetic beads for fast magnetic separation. The peak current of released FcSH had a good linear relationship with the thrombin concentration in the range of 0.1-5 nmol/L, and the detection limit of thrombin in the method was 0.06 nmol/L. The detection was also specific for thrombin without being affected by other proteins, such as immunoglobulin G, bovine serum albumin, lysozyme and human serum albumin. The method has been used to detect thrombin in human serum albumin with minimum background interference.     

A simple and direct electrochemical detection of interferon-gamma using its RNA and DNA aptamers

Tuberculosis is the most frequent cause of infection-related death worldwide. We constructed a simple and direct electrochemical sensor to detect interferon (IFN)-gamma, a selective marker for tuberculosis pleurisy, using its RNA and DNA aptamers. IFN-gamma was detected by its 5'-thiol-modified aptamer probe immobilized on the gold electrode. Interaction between IFN-gamma and the aptamer was recorded using electrochemical impedance spectroscopy and quartz crystal microbalance (QCM) with high sensitivity. The RNA-aptamer-based sensor showed a low detection limit of 100 fM, and the DNA-aptamer-based sensor detected IFN-gamma to 1 pM in sodium phosphate buffer. With QCM analysis, the aptamer immobilized on the electrode and IFN-gamma bound to the aptamer probe was quantified. This QCM result shows that IFN-gamma exists in multimeric forms to interact with the aptamers, and the RNA aptamer prefers the high multimeric state of IFN-gamma. Such a preference may describe the low detection limit of the RNA aptamer shown by impedance analysis. In addition, IFN-gamma was detected to 10 pM by the DNA aptamer in fetal bovine serum, a mimicked biological system, which has similar components to pleural fluid.     

以分子信标为报告分子的凝血酶检测新方法

以分子信标为报告分子,核酸适体为识别分子,发展了一种新的凝血酶检测方法.含有分子信标互补序列的核酸适体探针与凝血酶结合后,分子信标的荧光信号下降,从而得到凝血酶的浓度信息.该方法快速、灵敏,核酸适体探针无需荧光标记、设计简单,检测限达到0.83nmol/L.