By: Koji Sugioka, Yasutaka Hanada, Katsumi Midorikawa, Ikuko Shihira Ishikawa, Hiroyuki Kawano, Atsushi Miyawaki
RIKEN – Advanced Science Institute, Brain Science Institute
It is becoming increasingly important to observe and analyze the dynamics and functions of microorganisms both for fundamental investigations (such as elucidating the functions of biological cells) and for applications to biomicro systems and medicine. We used femtosecond (fs) laser 3D micromachining to fabricate microfluidic chips (which we term nanoaquariums) for observing microorganisms. Nanoaquariums enable us to drastically reduce the observation time relative to that for the conventional observation method using Petri dishes. Furthermore, they can be used to perform highly functional analysis, which biologists have long desired to realize. We have developed a technique for fabricating nanoaquariums that involves directly forming 3D hollow microstructures with smooth internal surfaces in photostructurable glass by fs laser direct writing followed by annealing and wet etching in dilute hydrofluoric acid (see Fig. 1). This technique permits rapid prototyping of 3D microfluidic systems with different structures, which is greatly desired by biologists for observing different microorganisms. Furthermore, functional microelements such as micromechanical elements and micro optical elements can be easily integrated into the microfluidic structure, permitting more functional observation and analysis to be performed.