Jiangsu Key Laboratory of Green Synthesis for Functional Materials, School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China.
Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China.
Anal Chem. 2021 Sep 28;93(38):12848-12853. doi: 10.1021/acs.analchem.1c02709. Epub 2021 Sep 14.
Quantum dot (QD)-based digital immunoassays play an important role in ultrasensitive biomarker detection. However, the requirement of an objective with a high numerical aperture (NA) limits the application of this immunoassay. Here, high-quality imaging of massive single-QDs was achieved by the combination of an air objective (20×/0.4 NA) and liquid-immersed microspheres (150 μm, = 2.2). The signal-to-noise ratio was comparable to that of a 100×/1.4 NA oil objective. Digital analysis of prostate-specific antigen (PSA) was performed within the dynamic range of 0-50 ng/mL and a limit of detection of 0.17 ng/mL. The measured serum data from the PSA were close to the values provided by a hospital. Using a low-magnification and low-NA objective may reduce the barrier of microscopy miniaturization and is beneficial to popularize biomolecular digital analysis.
基于量子点（QD）的数字免疫分析在超灵敏生物标志物检测中发挥着重要作用。然而，高数值孔径（NA）物镜的要求限制了这种免疫分析的应用。在这里，通过组合空气物镜（20×/0.4 NA）和液浸微球（150 μm， = 2.2）实现了大量单个量子点的高质量成像。信噪比可与 100×/1.4 NA 油镜相媲美。在 0-50ng/mL 的动态范围内和检测限为 0.17ng/mL 的情况下进行了前列腺特异性抗原（PSA）的数字分析。从血清中测量的 PSA 数据与医院提供的值接近。使用低倍率和低 NA 物镜可以降低显微镜小型化的障碍，有利于推广生物分子数字分析。
