Microscopic Raman Spectroscopy Analysis for Human Blood in Capillary
ZHANG Ming1，2, PENG Wen3, LAI Zhen-quan1, WANG Hong-peng2, YUAN Ru-jun2, HE Qiang2, WAN Xiong2*
1. Department of Physics, Nanchang University, Nanchang 330031, China
2. Shanghai Institute of Technical Physics, Chinese Academy of Sciences，Shanghai 200083, China
3. Shanghai Affiliated Hospital of China Metallurgical Corporation，Shanghai 200941, China
Abstract：The blood contains a variety of biological information such as hormones, enzymes, antibodies and so on. The detection and identification of numerous biological information in the blood can be used to determine and trace the origin of the blood species. Therefore, the development of blood analysis is of great significance to the fields such as criminal cases detection, species identification, disease prevention and so on. At present, the traditional blood detection methods are mostly microscopic observations, immunoassays and DNA/gene detection methods. These techniques can cause irreversible damage to blood samples and have problems such as long analysis cycle, complicated structure apparatus and high test prices. With the rise of laser technology, as a non-linear scattering spectroscopy, Raman spectroscopy is used in blood detection techniques. In blood detection techniques, Raman spectroscopy is usually combined with confocal microscopy to collect blood samples that have been coated on glass slides or in transparent containers because of its advantages like being fast, nondestructive, ect. However, complex optical systems and expensive experimental setups limit the widespread use of this technology. To provide a simple and easy-to-use method for detecting blood Raman, the Raman signal of human whole blood was collected and analyzed by a capillary-based Raman spectroscopy. Blood samples were sampled by siphon effect of the capillary. Compared with the loading of the carrier, the blood sample had the advantages of simulating human blood vessels, maintaining blood activity, reducing the degradation effect of oxygen on blood components and reducing the laser burns on blood samples. In order to avoid the fluorescence interference in the region of strong fluorescence of visible light, a 360 nm ultraviolet laser was used as an excitation light source to prevent the interference of the visible fluorescence signal. The integration time was set to 800 ms, which effectively avoided the burns on the blood sample caused by the laser irradiation for a long time which would affect the stability and authenticity of the experimental data. The average number was 2 times, aiming at avoiding the impact of inaccurate data caused by a single measurement. Spectral scanning range was 500~1 800 cm-1. The results showed that this range can better avoid the interference of the stronger fluorescence region of the visible light portion. The spectral signal at this time was processed by filtered denoising and baseline correction. Firstly, a 5-order discrete wavelet transform filter was used to decompose the signal at the first layer. The high-frequency noise signal was filtered out, and the low-frequency effective signal was retained to remove the spurious signal, and the effective signal of the spectrum was extracted. Secondly, baseline correction for the use of fourth-order polynomial fitting base and subtraction, aiming at achieving human whole blood capillary Raman peak signal extraction. Finally, the spectra obtained by inspecting the SDBS database and human blood samples were measured by reishaw confocal Raman spectroscopy to verify that some of the measured signals were Raman signals of several amino acid components in the human body. Experimental studies have found that the capillary-based Raman experimental system is more stable and repeatable than the conventional Raman probe system, and can effectively extract Raman spectrum signals in human whole blood, and its high Accuracy of confocal Raman microscopy system is cheaper, simpler and easier to be popularized, but the signal SNR and the peak intensity of the effective signal remain to be further improved. It is a possible solution to detecting human blood Raman signal.
张 铭，彭 文，赖珍荃，王泓鹏，袁汝俊，何 强，万 雄. 人全血的毛细管显微拉曼光谱分析[J]. 光谱学与光谱分析, 2019, 39(03): 797-801.
ZHANG Ming, PENG Wen, LAI Zhen-quan, WANG Hong-peng, YUAN Ru-jun, HE Qiang, WAN Xiong. Microscopic Raman Spectroscopy Analysis for Human Blood in Capillary. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(03): 797-801.
