Bioanalytical Material And Chip Fabrication Based On Orderly Porous Silicon

Orderly Porous Silicon (PSi) is an attractive inorganic porous material widely applied in biosensors field due to its high surface area, easy preparation, convenient surface chemistry, and optical signal transduction capability. In this paper, two different types of porous silicon was prepared by anodic electrochemical etching of bulk silicon wafer. Different surface modification was studied. Preliminary exploration of porous silicon application in the protein separation material, array, microfluidic technology and label-free cell analysis were studied.(1) It is summarized that the current studies situation and the developing direction of porous silicon. Preparation methods, Surface modification and application in biosensors of four different types of porous silicon were investigated. The development of porous silicon as biosensing material was studied based on different structures, such as Fabry-Perot, Double-layer PSi, Rugate filter and Microcavity. In addition, the importance of label-free cell analysis and the current common label-free optical cell analysis techniques were summarized.(2) Take use of the advantages of orderly porous silicon, such as optical sensing properties and accurately controllable porosity etc. PSi as the separation material can capture and enrichment low molecular weight proteins (LMWPs) from the complex biological samples, while protecting them from degradation by exogenous enzyme and maintaining their activity. Took BSA, HRP,Trypsin, Lysozyme and Insulin as model proteins, we get the linear relationship between molecular weight and cut-off porosity. Porous silicon particles modified with different functional groups were prepared. Its application to capture LMWPs from normal patients and colorectal cancer patients in clinical testing were studied. The results showed that the porous silicon has very good divisional ability and its accuracy is as high as80%.(3) Three kinds of preparation of porous silicon array methods were introduced and the comparation of the advantages and disadvantages was described. The porous silicon array technique expands its application in the fields of gas sensor and biosensor. PSi photonic crystal integrated with microfluidic will expand the application in biosensor, drug screening and cell analysis etc.(4) The microfluidic chips based on functionally modified Porous Silicon photonic crystal (PSiPC) and PDMS were designed to real-time analysis the behavior of cells when sitmulated by drug, such as the change of morphology, attachment and detachment etc. The C6cells were seeded into the PSiPC chip modified with TiO2. Light resonant with the photonic crystal is scattered by the cell layer and detected as an optical peak with a charge-coupled-device (CCD) spectrometer. It was demonstrated that exposure of C6to the toxins Cd2+leaded to morphology changes which caused a measurable decrease in Rugate Filter PSiPC peak intensity and a significant increase in effective optical thickness (EOT,2nL) in Fabry-Perot PSiPC. It was demonstrated the potential of the technique as a complementary tool for cell viability studies. The label-free method based on PSiPC presented here is noninvasive and can be performed in real time, representing a significant advantage compared to other techniques for in vitro monitoring of cell morphology.