Preparation Of Mono Layer Polystyrene Microspheres Array SERS Substrate And Its Used For Protein Detection

The surface enhanced Raman scattering(SERS) technology has been applied in various fields of scientific research since it was firstly found in 1974. With its advantages of high sensitivity, in situ, label-free testing, rich amount of information and abundant fingerprint region of the spectrum, SERS has attracted great attention in many fields, such as biological, physical fields. Meanwhile, SERS substrate is the key to the application of SERS technology in various fields. The design of new controllable, high sensitivity, good uniformity SERS substrates and their application in various fields become the power of the development of the SERS technology. Hence, in this paper, we prepared mono layer polystyrene microspheres array SERS substrate and used them for protein detection. The mainly work of thesis is as follows:1. Firstly, mono layer polystyrene microspheres(PS) particles film was prepared, then the DC sputtering method was used to sput silver and obtained surface roughness controllable nano-silver film. Sputtering ion current, shielding gas pressure and sputtering time were optimized in preparation. The benzenethiol molecule chosen as a probe of the properties of the substrates was characterized. The results showed that the mono layer polystyrene microspheres array SERS substrate was successfully prepared, and the substrate has a high sensitivity(R6G, 10-11 mol/L) with excellent signal reproducibility and homogeneity.2. The surface nano structure of the substrate was characterized by SEM, and the mechanism of its enhancement was speculated and the enhancement effect was judged by the enhancement factor. The prepared SERS substrate was applied in the lable-free detection of porcine reproductive and respiratory syndrome virus(PRRSV) and surface proteins of PRRSV monoclonal antibodies. The results showed that the enhanced factor of substrate could reach 1.7×106 and the detection method can successfully distinguished PRRS virus from the surface proteins with certain signal reproducibility.3. To overcome the shortcomings of the traditional biosensor, we designed an enzyme-like activity biosensor based on SERS technology. The above-mentioned substrate was used in the sensor. Human immunoglobulin(HIg G) was chosen as a model testing in construction of the new sensor. The results showed that HIg G has a good linear relationship from 0.001 ng/m L to 200 ng/m L, and the method behaved good specificity with a detection limit of 0.001 ng/m L. The results suggested that the proposed method behaved potential application in biological analysis, biosensing and other fields.