血液中含有众多生物信息, 如激素、 酶、 抗体等丰富的蛋白质成分。 通过对血液中众多生物信息进行检测鉴定可以起到对该血液种属判定、 溯源的目的。 因此, 血液检测技术的发展在诸如刑事案件侦破、 物种鉴定、 疾症预防等领域具有重要意义。 目前, 传统血液检测手段多为显微观测、 免疫法、 DNA/基因检测法等, 这些技术会对血液样本造成不可逆转的破坏性, 且存在分析周期长、 结构装置复杂、 试验价格昂贵等问题。 随着激光技术的发展, 拉曼光谱技术作为一种非线性散射光谱技术, 在血液检测技术中得到了应用。 在血液检测技术中, 拉曼光谱技术通常与共聚焦显微系统结合, 对涂在载玻片上或盛放在透明容器中的血液样品进行光谱信号采集。 该技术具有快速、 无损等优势, 但复杂的光路系统及昂贵的实验装置限制了该技术的广泛推广。 为提出一种装置简单、 操作简便的血液拉曼检测新技术, 研究采用基于毛细管的显微拉曼技术方案采集并分析人全血的拉曼信号。 血液样品通过毛细管的虹吸效应取样, 与载玻片的涂样方式相比毛细管的方案具有模拟人血管、 维持血液活性、 减小空气对实验过程中血液成分的影响、 降低激光对血液样品的灼伤效果等优势。 为避开可见光部分荧光较强区域的荧光干扰, 研究采用360 nm紫外激光器作为激发光源, 防止可见荧光信号的干扰。 积分时间设为800 ms, 有效避免因激光长时间照射对血液样品的灼伤效果, 影响实验数据的稳定性与真实性, 光谱平均次数为2次, 避免单次测量所带来的数据的不准确性影响。 光谱扫描范围为500～1 800 cm-1, 结果表明此范围内可较好的避开可见光部分荧光较强区域的干扰。 测得的拉曼光谱信号通过滤波去噪及基线校正进行处理。 首先采用5阶离散小波变换滤波, 进行1层信号分解, 滤除高频噪声信号, 保留低频有效信号, 从而去除杂散信号, 对光谱有效信号进行提取。 其次, 采用4阶多项式拟合扣除基底的基线校正, 实现人全血的毛细管显微拉曼光谱峰值信号的提取。 最终, 通过查询SDBS数据库以及人血样本通过reishaw共聚焦显微拉曼光谱仪测量所得光谱图进行验证发现测得信号中部分为人体内数种氨基酸成分的拉曼信号。 实验研究发现, 基于毛细管的显微拉曼实验系统与常规拉曼探头实验系统相比, 拉曼信号更稳定、 重复性高, 可有效提取人全血中的拉曼光谱信号, 而其与高精度的共聚焦显微拉曼系统相比价格便宜、 结构简单、 易于推广等优点, 但信号信噪比、 有效信号的峰值强度上仍有进一步的提升, 是一种测量人全血拉曼信号的可行方案。

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.