Lu Tianyi, Liu Miaoran, Xiao Yifei, Xu Yimeng, Wang Yu, Dai Ziyi, Qian Kai
State Key Lab of Environmental Adaptability for Industrial Products, Guangzhou 510275, China.
School of Integrated Circuits, Shandong University, Jinan 250100, China.
ACS Omega. 2025 Feb 7;10(6):6038-6046. doi: 10.1021/acsomega.4c10019. eCollection 2025 Feb 18.
Concentration and uniform deposition of particles during droplet evaporation remain significant challenges in analytical systems. This natural and appropriate design of the processing steps can effectively bridge the gap between the low-concentration test substance and the accuracy of the test tool and therefore has attracted widespread academic and industrial attention. However, conventional static evaporation faces two major challenges: limited concentration efficiency and nonuniform particle deposition due to the coffee-ring effect. Here, we introduce a "dynamic enrichment" method based on a magnetically actuated droplet manipulation platform, which fundamentally alters the traditional static concentration process. This approach enables both superior enrichment and uniform particle distribution on superhydrophobic surfaces through controlled droplet movement. We systematically investigated the enrichment behavior using model particles of varying densities and sizes under different experimental conditions, including droplet volume and initial concentration. The method demonstrates consistent performance across these diverse particle properties, achieving a higher concentration efficiency and more uniform deposition compared to static enrichment. Through characterization and mechanistic statements, we show that this platform could potentially serve as a foundation for developing sensitive analytical techniques, particularly considering that the working range of particle properties aligns well with those of common biological and chemical analytes.
在分析系统中，液滴蒸发过程中颗粒的浓缩和均匀沉积仍然是重大挑战。处理步骤的这种自然且恰当的设计能够有效弥合低浓度测试物质与测试工具准确性之间的差距，因此受到了学术界和工业界的广泛关注。然而，传统的静态蒸发面临两大挑战：浓缩效率有限以及由于咖啡环效应导致颗粒沉积不均匀。在此，我们基于磁驱动液滴操控平台引入一种“动态富集”方法，该方法从根本上改变了传统的静态浓缩过程。这种方法通过控制液滴运动，能够在超疏水表面实现卓越的富集效果以及颗粒的均匀分布。我们在不同实验条件下，包括液滴体积和初始浓度，使用不同密度和尺寸的模型颗粒系统地研究了富集行为。该方法在这些不同的颗粒特性方面表现出一致的性能，与静态富集相比，实现了更高的浓缩效率和更均匀的沉积。通过表征和机理阐述，我们表明该平台有可能为开发灵敏的分析技术奠定基础，特别是考虑到颗粒特性的工作范围与常见生物和化学分析物的范围非常契合。
