The Study and Application of Wavelength Modulation SPR Analyzer
|Keywords||SPR analysis Au/Ag alloy nanocomposites immunoassay|
With the first SPR biosensor was developed in1983，the application of SPR sensortechnology research includes almost all areas of modern biology. Whether it is in the lifesciences field, in the field of environmental and food safety, all have achieved rapiddevelopment. Currently, the SPR sensing technology is the most widely used to analyze theinteraction between biological molecules to get the reaction kinetics, combined with the sitesand the concentration of reactants information to other parties such as: immune regulation,gene regulation, antibody qualitative, information transduction. There have also been a lot ofvaluable information.At present, the application of SPR equipments are basical type of angle modulation. Themeasuring angle scopes are always limited and of the instrument itself is also more expensive.In the paper, the research prototype of wavelength detection SPR analyzer was developedsuccessfully and the specific structure of the various components of the instrument wasdescribed in detail. Meanwhile, the gold and silver alloy nanoparticles were prepared, whichwere used to the SPR sensor. The stability, reproducibility and sensitivity of the sensorperformance were improved obviously.SPR analyzer was composited from the light source, optical system, the sensing element, theflow cell, the spectrophotometric detection system and data processing systems. The incidentangle was fixed, wavelength was variable and using CCD as the detector. The method issimple, fast and the installation cost is moderate. With the wavelength modulation SPRanalyzer, multi-wavelength detection is easy to achieve at the same time and the detection wavelength range is unrestricted, so that not only the quality scope of the sensor surface to bedetected is unlimited, but also the change scope of refractive index is unlimited. Theinstrument is small, and the wavelength range is very wide that can be used for quantitativeanalysis, the interaction study between the molecules or molecules with the organization (eg,cells), and the interaction of biomolecules and biological molecules with drug molecules. TheSPR detector that matched with the analyzer-miniature fiber optic spectrometers wasdesigned and assemblied with optical fiber input metering, holographic diffraction gratingfixed, linear CCD photoelectric sensor detection. The SPR instrument can be applied as adetection unit and other spectral analysis field.A novel method for detecting Human IgG is reported, which based on Au/Ag alloynanocomposites for amplifying surface plasmon resonance response. Au/Ag alloynanocomposites were characterized in detail by transmission electron microscopy (TEM),UV-vis absorption spectroscopy and X-ray photoelectron spectroscopy (XPS). Covalentimmobilization of about24nm diameter of Au/Ag alloy nanocomposites on the Au filmresults in a large shift in resonance wavelength, which is due to the increase of the thicknessof the sensing membrane, high dielectric constant of Au/Ag nanoparticles, andelectromagnetic coupling between Au film and Au/Ag alloy nanocomposites. Based on Au/Agalloy nanocomposites, the SPR biosensor exhibits a satisfactory response for human IgG inthe concentration range of0.15-20.00μg mL-1. While the biosensor based on Au nanoparticlesfor human IgG, a response for human IgG in the concentration range of0.60-20.00μgmL-1.Therefore, Au/Ag alloy nanoparticles through chemical connections in the gold film caneffectively improve the sensitivity of SPR biosensor.