Ino Kosuke, Mashiko Miyu, Kanno Yusuke, Tang Yeyi, Masui Shuzo, Nisisako Takasi, Hiramoto Kaoru, Abe Hiroya, Shiku Hitoshi
Graduate School of Engineering, Tohoku University, 6-6-11-604 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan.
Institute of Integrated Research, Institute of Science Tokyo, Yokohama 226-8503, Japan.
Anal Chem. 2024 Dec 3;96(48):18967-18976. doi: 10.1021/acs.analchem.4c03167. Epub 2024 Nov 18.
Spherical biosamples such as immunobeads, cells, and cell aggregates have been widely used in bioapplications. The bioactivity of individual spherical biosamples in highly sensitive assays and individual analyses must be evaluated in a high-throughput manner. Electrochemiluminescence (ECL) imaging was recently proposed for the high-throughput analysis of diffusive molecules from spherical biosamples. ECL imaging involves the placing of spherical biosamples on a flat electrode filled with a solution. The biosamples produce (or consume) biological/chemical molecules such as HO and O, which diffuse to form a concentration gradient at the electrode. The ECL signals from the molecules are then measured to obtain the concentration profile, which allows the flux to be estimated, from which their bioactivities can be successfully calculated. However, no studies on theoretical approaches for spherical biosamples on flat surfaces have been conducted using ECL imaging. Therefore, this paper presents a novel spherical diffusion theory for spherical biosamples on a flat surface, which is based on the common spherical diffusion theory and was designated as the extended spherical diffusion theory. First, the concepts behind this theory are discussed. The theory is then validated by comparison with a simulated analysis. The resulting equation successfully expresses the concentration profile for the entire area. The glucose oxidase activity in the hydrogel beads is subsequently visualized using ECL imaging, and the enzymatic product flux is calculated using the proof-of-concept theory. Finally, a time-dependent simulation is conducted to fill the gap between the theoretical and experimental data. This paper presents novel guidelines for this analysis.
诸如免疫珠、细胞和细胞聚集体等球形生物样本已在生物应用中广泛使用。在高灵敏度检测和个体分析中，必须以高通量方式评估单个球形生物样本的生物活性。最近有人提出用电化学发光（ECL）成像对来自球形生物样本的扩散分子进行高通量分析。ECL成像包括将球形生物样本放置在充满溶液的平面电极上。生物样本产生（或消耗）诸如HO和O等生物/化学分子，这些分子扩散并在电极处形成浓度梯度。然后测量这些分子的ECL信号以获得浓度分布，从而可以估算通量，进而成功计算出它们的生物活性。然而，尚未有关于使用ECL成像对平面上的球形生物样本进行理论方法的研究。因此，本文提出了一种针对平面上球形生物样本的新型球形扩散理论，该理论基于常见的球形扩散理论，被命名为扩展球形扩散理论。首先，讨论了该理论背后的概念。然后通过与模拟分析进行比较来验证该理论。所得方程成功地表达了整个区域的浓度分布。随后使用ECL成像可视化水凝胶珠中的葡萄糖氧化酶活性，并使用概念验证理论计算酶促产物通量。最后，进行了时间相关模拟以填补理论数据与实验数据之间的差距。本文为此分析提出了新的指导原则。
