Detection And Enrichment Of S-layer Protein Of Lactobacillus Acidophilus Based On Porous Materials

Lactobacillus is an important probiotic in the human gut, which has a certain inhibitory effect on the pathogens and can regulate the immune function of the body. Surface layer protein(SLP) is a kind of protein on the surface of cell membrane or cell wall, which is an important adhesion factor for lactic acid bacteria colonization on the intestinal tract to play a probiotic role. At present, the detection method of S-layer protein is costly and complicated,and the traditional method of protein purification is cumbersome. Therefore, rapid and effective detection and enrichment of S-layer protein has important research significance. In this paper, we based on two kinds of porous materials to build S-layer protein rapid detection and enrichment of optical sensors, including photonic crystal molecular imprinting materials and porous silicon material. The main research contents and results are as follows:First, the S-layer protein was purified by chromatography to be used for the construction and response of subsequent sensing materials. The anti-S-layer protein monoclonal antibody was prepared by immunization method to construct the porous silicon bio-optical sensor. The result of purification of S-layer protein was good, and the titer of the S-layer protein monoclonal antibody was ? 128K.The monodisperse SiO2 particles were prepared by Stober method. The colloidal crystals were prepared by Vertical subsidence self - assembly. The photonic crystals were combined with molecular imprints to construct the anti-opal hydrogel response material. The material had a three-dimensional ordered macroporous structure with spectroscopic self-expression and fast response speed, the rapid detection of S-layer protein can be achieved.The imprinting holes of S-layer protein were prepared on the surface of hydrogel by surface blotting, the shape of protein was complementary to the imprinting holes, and it had high selectivity and high sensitivity to S-layer protein. It had good linearity for the response of different concentrations of S-layer protein, and could achieve the linearity of S-layer protein content in crude protein detection, response time within 3 minutes. In addition, the material had a certain enrichment effect on the S-layer protein in the crude protein of Lactobacillus acidophilus surface protein, therefor it was expected to realize the purification of S-layer protein.The sensor of on-line detection of S-layer protein was prepared by the combination of porous silicon with antigen-antibody reaction. Monolayer silicon was prepared by anodic oxidation of monocrystalline silicon and its surface was modified with titanium dioxide to increase its stability.' The obtained porous silicon had good reflection interference performance. The on-line real-time monitoring of the sample was achieved by combining the porous silicon with the microfluidic technique, which had a high selectivity and sensitivity to the S-layer protein and showed good linearity in response to different concentrations of S-layer protein. It could be achieved on the unknown concentration of S-layer protein content determination, the response time was about 5 minutes.