The Miniaturization And Integration Research Of The Key Technologies Of Cell Processing And Analysis

With the rapid development of space technology, spacebiology is attracting more and more attention. The ability doing an experiment of biological study depends on the development of instruments in space. However, the lack of sample processing and on- line analytical technology in space impedes the in-orbit testing. There are many limiting factors to this dilemma. Firstly, the difficulty of cell processing in space is caused by the complexity of biological sample. Secondly, current technologies in offline mode are lack of automated feature. Major obstacle is that the instruments based on the ground cannot adapt to the space environment. Therefore, it is necessary to develop an in-orbit integrated system with the function of sample processing, analysis and detection.To satisfy the urgent needs described above, this research focused on the key technology of cell processing and testing adapted to the space environment. Considering of the space environment, a cell processing principle prototype and LED induced fluorescence detectors were developed, which were featured miniaturization, low power consumption and automation. The environmental adaptability test will be finished when the engineering prototype was developed. This work will benefit for the in-orbit detection of biological samples in space.The main contents include the following sections:1. For the requirements of the spacebiology research, the experimental design based on microfiltration was built and a cell processing principle prototype was developed which was adapted to the space micro-gravity environment. Cell cleaning, lysis, cell contents release and derivation will be finished in this device. Based the thought of module design, the prototype was characterized by miniaturization, integration and automation. The device provides a more efficient method for cell processing in space.2. A LED-induced fluorescence detector(LED-IFD) was developed based on the orthogonal optical path. The small LED fiber source was developed and used as the exciting light source of fluorescence detector instead of laser. A homemade fiber & capillary self-calibration platform could ensure that exciting light can be coupled precisely into the capillary. Fluorescence was collected by the objective lens and transmitted to the PMT which was able to convert the light into electrical signals. These signals were recorded and processed with a computer using in- house written software. The detection limit for sodium fluorescein was 10-8 mol/L. Compared with traditional laser- induced fluorescence detector, the advantage of this detector was small size, light weight and low power consumption with the benefit from the usage of fiber and LED which achieved the purpose of miniaturization.3. A LED-IFD based on the unbalanced coupling fiber was present in this paper. The unbalanced coupling fiber was used as the light path of exciting light and fluorescence. The exciting light directly excited the fluorescent reagent in the flow path of "V"- type detection cell. This windowless flow cell reduced the loss of exciting light caused by interface reflection and the detection limit obtained from this system for sodium fluorescein was 10-9 mol/L. The device volume was further reduced benefiting from the unbalanced coupling fiber and "V"-type detection cell. The requirement of installation, commissioning, and maintenance was reduced due to the use of standard SMA interface in this device.4. Wavelet transform was applied to the denoising of chromatographic data. The simulated chromatography signal and a real signal respectively were used to optimize the parameter(includ ing threshold functions, threshold estimation methods, wavelets and decomposition levels) with the indexes of peak height, area and SNR. The comparison experiments showed that the optimal wavelet parameter was soft threshold function, Universal threshold, sym2 wavelet and decomposition level 12. Compared with the median filter, the result of wavelet threshold denois ing had higher peak signal to noise ratio. This method was helpful to improve the detection sensitivity of low abundance biological sample in space and significant in extend the detection range.