Single-Microparticle Based Analyses under Solution Flow Conditions

显微光谱学和微电化学系统与流体歧管相结合，被开发用于操纵和分析单个微粒，如聚合物珠、油滴、活细胞等。通过使用设置在显微镜载物台上的流动池，将含有微粒的水溶液引入池中。对于聚合物珠通过激光捕获固定单个颗粒，对于油滴通过微毛细管的顶端固定单个颗粒，或者对于活细胞通过粘附固定在壁上，其它未固定的颗粒通过足够量的水流完全泵出到细胞中。这些程序可以在细胞中只保留单个粒子。此外，通过使用适当的流体歧管，可以将任意试剂引入到池中，使得可以通过显微光谱和/或微电化学方法监测颗粒的化学/物理响应的时间分布，而不受其他颗粒的干扰。在溶液流动条件下研究了三种不同的化学/生化过程：1）激光捕获-吸收显微光谱法研究单个离子交换树脂珠的离子交换动力学; 2）显微注射-显微光谱法研究单个油滴的液/液萃取动力学; 3）单个活细胞（酿酒酵母）的染料染色动力学根据溶液流速和颗粒直径讨论了离子交换、萃取或染色速率和效率。

Microspectroscopy and microelectrochemical systems combined with a fluid manifold were developed to manipulate : and analyze single microparticles such as polymer beads, oil droplets, living cells, and so forth. By using a flow cell set on a microscope stage, an aqueous solution containing microparticles is introduced to the cell. With a single particle being fixed by laser-trapping for polymer beads, on the top end of a microcapillary for oil-droplets, or on the wall by adhesion for living-cells, other non-fixed particles are pumped out completely by flow of sufficient amount of water to the cell. These procedures can hold exclusively the single particle in the cell. By using an appropriate fluid manifold, furthermore, an arbitrary reagent can be introduced to the cell, so that a temporal profile of chemical/physical responses of the particle would be monitored by microspectroscopic and/or microelectrochemical method(s) without interference by other particles. Three different chemical/biochemical processes were studied under solution-flow conditions :1) Ion-exchange dynamics of a single ion-exchange-resin bead by laser trapping-absorption microspectroscopy.2) Liquid/liquid extraction dynamics of a single oil-droplet by microinjection - microspectroscopy.3) Dye-staining dynamics of a single living-cell (Saccharomyces cerevisiae)The ion-exchange, the extraction, or the staining rate and efficiency were discussed in terms of the solution flow rate and the particle diameter.