Preparation And Application Of Biochip Carriers Based On Nano-membranes

Based on microelectronics, biology, physics, chemistry and computer sciences, biochip (or biologic microarray), which developed with Human Genome Project (HGP) and as first used in 1990s, marked a new era of micro-analysis technology.The first step of biochip manufacture is to prepare the carrier material. In this process, the glass slide need to be modified so that different probes can be immobilized on the slide surface with fastness, specificness and stability. Chemical modification on the glass slide surface is a key step in biochip fabrication, theoretical and applied research on the modification methods will therefore have great significance for the development of microarray technology.The study of biochip carrier based on nano-membranes has put forward under this background. The glass slides with flat and clean surface are used in these experiments. The surface modification includes nano-membrane assembling and then function-loading on the glass slides. By optimizing experimental conditions, new methods for preparation of biological chip carriers based on different nano-membranes have been established with the advantage of higher chemical stability and superior immobilizing efficency, and could find practical applications in the areas of life science reseach and related industries.1. Cleaned glass slides were dipped into the colloidal TiO2 solution prepared by sol-gel method. After coated with TiO2 nano-membrane, dried at room temperature and calcined at high temperature, the slides were silanized by treating with 3-aminopropyl trimethoxysilane reagent, thus the aminating biochip carriers were prepared and characterized by fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM) and fluorescence microscope. The results showed that"linkers"with amino groups can be immobilized uniformly on the modified surface. To test the immobilizing efficency, fluorescein isothiocyanate (FITC) was use as a simulating probe, the experimental results showed that the fluorescence intensity of the samples was superior to those slides treated only with silanization.2. Colloidal nano-SiO2 was prepared by the sol-gel method and coated on the surface of cleaned glass slides by a dip-coating technique to form SiO2 nano- membrane. After calcined at high temperature, the slides were silanized by treating with 3-aminopropyl trimethoxysilane in ethanol solution, and the biolochip carriers with amino groups were formed. The sample slides were characterized by FTIR, SEM and atomic force microscopy(AFM). The probe immobilization efficiency of these carriers were tested with FITC and bovine serum albumin (BSA). The results showed that the performance of improved carriers was superior to those carriers treated only with silanization. The influential factors on the performance of biochip carriers based on nano-SiO2 film, including component ratio of the reagents, acidity of hydrolysis and polycondensation, temperture of the reaction system were studied in detail.3. The slides coated with nanostructure SiO2 thin film were silanized byγ-mercaptopropyl trimethoxysilane and then dipped into the colloidal gold prepared by Frens method, thus the biochip carriers based on nano-gold film prepared. The immobilization efficiency of protein probes on these carriers was 11.3 times higher than those treated only with silanization. The influential factors on the performance of nano-gold film including dosage of reagents, reaction time and the stirring rate were studied, and the optimum conditions for preparation of nano-gold-film carriers were established.4. Colloidal TiO2 was prepared by the sol-gel method. Nano-TiO2 and poly(sodium 4-styrenesulfonate) salt (PSS) complex thin films were fabricated on clean slides by the electrostatic self-assembly (ESA) method. The slides with ESA films were then silanized by treating with 3-aminopropyl trimethoxysilane reagent. The results showed that these carriers had high efficiency of immobilizing FITC, and the fluorescence intensity, density and evenness were superior to those slides treated only with silanization. Effective connection in upper/lower layers between TiO2 films at acid conditions (pH=1) and PPS films provides the carrier high performaces in the scratch-resistance and cohesion tests. Silanization on the ESA film in 10% APS solution for 30 minutes makes the sample carriers better at the immoblization of probe.