Microfluidic devices for real-time observation of yeasts using laminar flows

Abstract

Real time monitoring of microbial cultivation has received attention to achieve rapid and quantitative image analysis technique. Polydimethylsiloxane (PDMS) microfluidic devices are widely used for optical microscope observation. However, it is difficult to use the devices continuously because the yeasts adsorbed on PDMS walls. To overcome this problem, the PDMS microfluidic devices consisted of a single microchannel with three branch channels as inlets and outlets was fabricated to flow the yeasts in the center of the single channel without adsorption of the yeast on PDMS walls. In this study, we investigated the relationship between the flow rate and the recovery rate of the flow from the outlet. Ultrapure water was used for the sheath flow and culture medium containing the yeasts was used for the sample flow. The yeasts adsorption was inhibited when the flow rate of the sheath flow was three times higher than that of the 0.25 mL/min central sample flow. The yeasts recovery rate of the sample flow was 73 wt%. These results suggest that the yeasts were circulated to observe their morphologies in real-time monitoring.