Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745, Jena, Germany.
Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07745, Jena, Germany.
Anal Bioanal Chem. 2018 Jan;410(3):999-1006. doi: 10.1007/s00216-017-0609-y. Epub 2017 Sep 13.
A new approach is presented for cell lysate identification which uses SERS-active silver nanoparticles and a droplet-based microfluidic chip. Eighty-nanoliter droplets are generated by injecting silver nanoparticles, KCl as aggregation agent, and cell lysate containing cell constituents, such as nucleic acids, carbohydrates, metabolites, and proteins into a continuous flow of mineral oil. This platform enables accurate mixing of small volumes inside the meandering channels of the quartz chip and allows acquisition of thousands of SERS spectra with 785 nm excitation at an integration time of 1 s. Preparation of three batches of three leukemia cell lines demonstrated the experimental reproducibility. The main advantage of a high number of reproducible spectra is to apply statistics for large sample populations with robust classification results. A support vector machine with leave-one-batch-out cross-validation classified SERS spectra with sensitivities, specificities, and accuracies better than 99% to differentiate Jurkat, THP-1, and MONO-MAC-6 leukemia cell lysates. This approach is compared with previous published reports about Raman spectroscopy for leukemia detection, and an outlook is given for transfer to single cells. A quartz chip was designed for SERS at 785 nm excitation. Principal component analysis of SERS spectra clearly separates cell lysates using variations in band intensity ratios.
提出了一种新的细胞裂解物鉴定方法,该方法使用 SERS 活性银纳米粒子和基于液滴的微流控芯片。通过将银纳米粒子、作为聚集剂的 KCl 以及含有细胞成分(如核酸、碳水化合物、代谢物和蛋白质)的细胞裂解物注入连续流动的矿物油中,生成 80 纳升的液滴。该平台能够在石英芯片蜿蜒通道内准确混合小体积,并允许以 785nm 激发获取数千个具有 1s 积分时间的 SERS 光谱。对三批三种白血病细胞系的制备证明了实验的可重复性。大量可重复光谱的主要优势在于可以对大量样本进行统计学分析,并得到稳健的分类结果。支持向量机采用留一法交叉验证,对 Jurkat、THP-1 和 MONO-MAC-6 白血病细胞裂解物的 SERS 光谱进行分类,其灵敏度、特异性和准确性均优于 99%。该方法与先前关于拉曼光谱用于白血病检测的已发表报告进行了比较,并对转移到单细胞进行了展望。设计了一种用于 785nm 激发 SERS 的石英芯片。SERS 光谱的主成分分析通过带强度比的变化清楚地区分细胞裂解物。