p H敏感高分子因其独特的 p H敏感性质而在药物的控制释放 [1,2 ] 、分子分离 [3 ] 以及生物传感器 [4 ]等方面得到应用 .应用于免疫分析时 ,要求 p H敏感高分子在溶液 p H 7.4左右波动时做出响应 ,过多偏离生理 p H会对免疫反应生成的抗原 -抗体复合物造成不同程度的破坏 .目前 ,p H敏感高分子并未在免疫分析中广泛应用 ,这主要是由于高分子的相转变 p H大多在 4或 1 0左右[5,6] .我们 [7] 曾合成了3 7℃下相转变 p H在 5 .6左右的 p H敏感高分子 ,并将其作为免疫反应载体 ,建立了乙肝表面抗原的分析系统 ,虽然其相转变 p H比以往的高… 相似文献
Three immobilization modes of antigen to the polymers in the pH‐sensitive phase separation immunoassay were investigated and compared. The results showed that the immobilization mode in the presence of N‐ethyl‐N′‐(3‐dimethylaminopropyl)carbodiimide hydrochloride (EDCI) rendered the most desirable results. The immobilization efficiencies and immunological reaction activities of immobilized antigen of this mode were improved over the other two modes. The novel immobilization mode by EDCI was used in the pH‐sensitive phase separation immunoassay for rabbit IgG (Ag). In the competitive immunoassay, immobilized Ag and the standard Ag (or sample) competed for binding to a horseradish peroxidase labeled antibody at 37°C in a homogeneous format. After changing the pH to separate the polymer‐immune complex, the complex precipitate was re‐dissolved and determined by coupling with the color reaction of hydrogen peroxide and o‐phenylenediamine. The linear range of this determination was between 100–1400 ng/mL. Compared to the traditional enzyme‐linked immunosorbent assays (ELISA) using the same reactants, the proposed method was quiet fast (the time decreased from 100?120 to 30 min) and showed similar sensitivity, i.e., 6.0 ng/mL. 相似文献
A series of novel pH‐ and temperature‐responsive diblock copolymers composed of poly(N‐isopropylacrylamide) (PNIPAM) and poly[(L ‐glutamic acid)‐co‐(γ‐benzyl L ‐glutamate)] [P(GA‐co‐BLG)] were prepared. The influence of hydrophobic benzyl groups on the phase transition of the copolymers was studied for the first time. With increasing BLG content in P(GA‐co‐BLG) block, the thermal phase transition of the diblock copolymer became sharper at a designated pH and the critical curve of phase diagram of the diblock copolymer shifted to a higher pH region. Notably, when the BLG content in P(GA‐co‐BLG) block was more than 30 mol.‐%, the diblock copolymer responded sharply to a narrow pH change in the region of pH 7.4–5.5.
Abstract A novel, selective, and sensitive magnetic-mimetic enzyme fluorescence immunoassay method for antigen detection has been developed by taking advantage of a magnetic separation process and the amplification feature of the hemin label. This method is based on a twice amplified fluorescence signal. The signal is first amplified due to the ultrasmall size and the high surface-to-volume ratio of the silica-coated magnetite nanoparticles, which enable the nanoparticles to carry much more antibodies. Second, the mimetic enzyme (hemin) as a labeling reagent catalyzes the reaction of p-hydroxyphenyl acetic acid and H2O2 can further amplify the fluorescence signal. This protocol was also evaluated for a sandwich-type immunoassay of human IgG, and the calibration graph for human IgG was linear over the range of 0–100 ng mL?1 with a detection limit of 9.8 ng mL?1. This method can easily separate magnetic nanoparticles from the solution, which simplified the process and played a promising role for various applications in immunoassay. 相似文献
A pH sensitive near-infrared (NIR) fluorescent probe, IR-DO3A, was synthesized. It was based on combination of tricarbocyanine that had typical NIR absorption and fluorescent emission spectrum, and DO3A (1,4,7,10-tetra azacyclododecane -1,4,7-triyl)triacetic acid) that had three side chain of carboxylic acids. Phenyl sulfonamide that was used to maintain the density of electronic cloud of tricarbocyanine backbone and improve the solubility of the whole molecule was selected to connect tricarbocyanine and DO3A by several substitution reactions under some certain conditions. The final product, IR-DO3A was confirmed by NMR and MS spectrums, and had a better solubility in polar solvent than tricarbocyanine. The optical properties of IR-DO3A in two mixture solvents were studied. It had maximum Uv-vis absorption at 750nm and 805nm, fluorescent emission at 808nm, all these wavelengths were in NIR range and there was a 58nm Stokes-Shift. Also its optical properties at different pH in water were studied and it was sensitive in pH 6~9, which related with the protonation and deprotonation processes of IR-DO3A at different pH. These pH sensitive and NIR-fluorescent properties may result in an application for revealing the pH changes of physiological diseases. 相似文献
