3D microfluidic chips with integrated functional microelements fabricated by a femtosecond laser for studying the gliding mechanism of cyanobacteria

Abstract

Phormidium, a genus of filamentous cyanobacteria, forms endosymbiotic associations with seedling roots that accelerate the growth of the vegetable seedlings. Understanding the gliding mechanism of Phormidium will facilitate improved formation of this association and increased vegetable production. To observe the gliding movements, we fabricated various microfluidic chips termed nanoaquariums using a femtosecond (fs) laser. Direct fs laser writing, followed by annealing and successive wet etching in dilute hydrofluoric acid solution, can easily produce three-dimensional (3D) microfluidics with different structures embedded in a photostructurable glass. Using the fs laser, optical waveguides and filters were integrated with the microfluidic structures in the microchips, allowing the gliding mechanism to be more easily clarified. Using this apparatus, we found that CO(2) secreted from the seedling root attracts Phormidium in the presence of light, and determined the light intensity and specific wavelength necessary for gliding.

Ultrafast lasers—reliable tools for advanced materials processing

“…106 This approach has also enabled the fabrication of ca 40 mm long nanofluidic channels with widths of ca 40 nm, 37,107 as shown in Figure 6. The unique ability of direct femtosecond laser writing to simultaneously alter the chemical and optical properties of bulk glass materials provides new avenues to fabricate a variety of integrated microfluidic and optofluidic microsystems/devices such as microfluidic lasers, 108 nanoaquariums to observe and determine the functions of living organisms, 109,110 optofluidic sensors with various functions including liquid concentration analysis, 111,112 single-cell detection and manipulation systems [113][114][115] and devices for the rapid screening of algae populations. 116 The latest progress is aimed at realizing an optofluidic sensor by coating the inner wall of a microfluidic channel with a polymer, as illustrated in Figure 11a.…”

In-channel integration of designable microoptical devices using flat scaffold-supported femtosecond-laser microfabrication for coupling-free optofluidic cell counting

“…6,15,35 Here, a system based on a new concept is presented by utilizing glass optofluidic chips integrated with polymer microlenses, as illustrated in Fig. S8b).…”

Femtosecond Laser 3D Fabrication in Porous Glass for Micro- and Nanofluidic Applications

“…The same technique has been extended to fabricate free-space optics such as micromirrors and micro-optical lenses in glass materials [12][13][14]. By virtue of its unique ability to build different types of functional components into a monolithic glass substrate, femtosecond laser direct writing offers a flexible approach to fabricate a wide variety of integrated microsystems and devices such as microfluidic lasers [15], optofluidic sensors [16][17][18][19][20][21], micro-electrodes [22][23][24][25][26] and micro-mechanics [27,28].…”