基于单颗粒LSPR成像技术的呼出气中醛类物质检测研究

The development of high efficient, noninvasive and sensitive lung cancer biomarker detection method is the key to early diagnosis of lung cancer and to improving the patients’ survival rate. Prior studies have demonstrated that exhaled aldehydes are strongly correlated with the occurrence and development of lung cancer, which can be considered as an important biomarker for lung cancer screening. However, due to complex composition of exhaled breath and extremely low content of aldehydes, conventional aldehydes detection methods are difficult to be used directly for the detection of exhaled aldehydes. With respect to the above, it is of great significance to develop a new high-performance detection method of exhaled aldehydes with ultra-low concentration for the screening and early diagnosis of lung cancer. Single-particle imaging technique is particularly suitable for the analysis of low-concentration samples as it adopts a single nanoparticle as a measurement unit, accompanied by advantages of high spectral resolution, high signal-to-noise ratio and low detection limit. The aim of this project is to establish a detection platform for exhaled aldehydes by using gold particles modified with specific recognition groups of aldehydes as probes, and single-particle spectral imaging technology as an approach to correlate single-particle LSPR spectral changes with the concentration of aldehydes. Based on the platform provided in this project, it is expected to compare the difference of total exhaled aldehyde content in healthy individuals and lung cancer patients. On the other hand, multiple linear regression model is designed to be used to analyze the content of various aldehydes in the above two samples, so as to lay a foundation for further research on the correlation between exhaled aldehydes and lung cancer.

发展高效、无创、灵敏的肺癌标志物检测方法，是实现肺癌早期诊断，提高患者生存率的关键。研究发现，呼出气中醛类物质与肺癌的发生发展、密切相关，可作为判别肺癌的重要标志物。然而，呼出气组成复杂，醛类物质含量极低，致使常规的醛类检测方法难直接用于呼出气中醛类物质的检测。因此，发展一种呼出气中超低浓度醛类物质高效检测的新方法，对肺癌筛查和早期诊断具有重要意义。单颗粒成像技术以单个纳米粒子为测量单元，光谱分辨率高、信噪比高、检测限低，尤为适合低浓度样品的分析。本项目拟以修饰了醛类物质特异性识别基团的金颗粒为探针，以单颗粒光谱成像技术为手段，将单颗粒LSPR光谱变化与醛类物质浓度相关联，建立一个呼出气中醛类物质的检测平台。基于此平台，一方面，比较健康人和肺癌患者呼出气中总醛含量差别；另一方面，利用多元线性回归模型，分析两类样本中各种醛类分子的分量，以期为呼出气中醛类物质与肺癌相关性的深入研究打下基础。

呼出气中的醛类物质可作为判别肺癌的重要标志物。但是，呼出气组成复杂，醛类物质含量极低。因此，发展一种呼出气中超低浓度醛类物质的高效检测方法，对肺癌筛查和早期诊断具有重要意义。本项目研究过程中，基于表面增强拉曼散射(SERS)技术，开发了一种环境友好的醛类物质检测平台（10 min内完成检测，且检测限均在ng/mL水平）。研究内容主要有：1. 基于对银纳米三角的后合成修饰，构建了一类高性能SERS基底（AgTNPs@Fe），既提高了基底的SERS活性，也具备在一定的抗卤素离子干扰能力。通过基底与酸性衍生化结合的方法，研究其在呼出气冷凝液及血清中醛类物质检测中的应用（一种呼出气冷凝液及血清中甲醛的检测方法，发明专利，申请号：202110504019.X，2021.05.10）。2. 以DNA为探针，开展了As在金纳米粒子(AuNPs)上的吸附研究。在高浓度盐环境下，DNA的存在，会阻止AuNPs发生聚集；但当有As存在时，As会阻止DNA在AuNPs上的吸附，从而导致AuNPs的聚集。根据这一原理，通过拉曼、比色、等热滴定等系列实验，最终证实了是As和AuNPs的相互作用，干扰了DNA在AuNPs上的吸附从而导致了在高盐环境下AuNPs的聚集。并且，通过对文献中已报道的As的适配体和随机DNA序列的进一步研究，验证了DNA和As之间的作用远小于.As和AuNPs之间的作用（Langmuir, 2019,35, 7307-7311；Anal.Chem, 2019, 91, 10887-10893）。3. 基于表面增强拉曼散射（SERS）光谱技术的环境中挥发性污染物现场快捷检测系统研究。提供了一种微型化便携式吹扫捕集装置，构建了可用于现场实时检测的便携式检测系统，用于挥发性样品的前处理富集，具有样品用量少、耗时短等特点；搭载了微型化拉曼光学检测模块，使用人机直接交互的模式实现挥发性有害物质的现场实时定量检测。以土壤中苯硫酚为检测模型，以金纳米颗粒(AuNPs)为增强基底，利用此系统对土壤中的苯硫酚进行了定性和定量分析，检出限为0.104μg/g，RSD在4.2%~6.2%之间，整体实验结果重现性良好。