Surface Microfabrication of Conventional Glass Using Femtosecond Laser for Microfluidic Applications
Takuma Niioka and Yasutaka Hanada†
3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
Recently, a lot of attention has been paid to a single-cell analysis using microfluidic chips, since each cell is known to have several different characteristics. The microfluidic chip manipulates cells and performs high-speed and high-resolution analysis. In the meanwhile, femtosecond (fs) laser has become a versatile tool for the fabrication of microfluidic chips because the laser can modify internal volume solely at the focal area, resulting in three-dimensional (3D) microfabrication of glass materials. However, little research on surface microfabrication of materials using an fs laser has been conducted. Therefore, in this study, we demonstrate the surface microfabrication of a conventional glass slide using fs laser direct-writing for microfluidic applications. The fs laser modification, with successive wet etching using a diluted hydrofluoric (HF) acid solution, followed by annealing, results in rapid prototyping of microfluidics on a conventional glass slide for fluorescent microscopic cell analysis. Fundamental characteristics of the laser-irradiated regions in each experimental procedure were investigated. In addition, we developed a novel technique combining the fs laser direct-writing and the HF etching for high-speed and high-resolution microfabrication of the glass. After establishing the fs laser surface microfabrication technique, a 3D microfluidic chip was made by bonding the fabricated glass microfluidic chip with a polydimethylsiloxane (PDMS) polymer substrate for clear fluorescent microscopic observation in the microfluidics.
-  S. S. Saliterman, “Fundamentals of BioMEMS and Medical Microdevices,” Wiley-Interscience: Washington, 2005.
-  M. J. Jebrail, M. S. Bartsch, and K. D. Patel, “Digital Microfluidics: A Versatile Tool For Applications in Chemistry, Biology and Medicine,” Lab Chip, Vol.12, pp. 2452-2463, 2012.
-  A. M. Streets and Y. Huang, “Chip in a lab: Microfluidics for next generation life science research,” Biomicrofluidics, Vol.7, pp. 011302-1-011302-23, 2013.
-  E. K. Sackmann, A. L. Fulton, and D. J. Beebe, “The present and future role of microfluidics in biomedical research,” Nature, Vol.507, pp. 181-189, 2014.
-  M. Yang, C. W. Li, and J. Yang, “Cell Docking and On-Chip Monitoring of Cellular Reactions with a Controlled Concentration Gradient on a Microfluidic Device,” Anal. Chem., Vol.74, pp. 3991-4001, 2002.
-  H. Liua and Y. Ito, “Cell attachment and detachment on micropattern-immobilized poly(N-isopropylacrylamide) with gelatin,” Lab Chip, Vol.2, pp. 175-178, 2002.
-  J. E. Ali, P. K. Sorger, and K. F. Jensen, “Cells on chips,” Nature, Vol.442, No.27, pp. 403-411, 2006.
-  Y. C. Toh, C. Zhang, J. Zhang, Y. M. Khong, S. Chang, V. D. Samper, D. V. Noort, D. W. Hutmacher, and H. Yu, “A novel 3D mammalian cell perfusion-culture system in microfluidic channels,” Lab Chip, Vol.7, pp. 302-309, 2007.
-  D. H. Kim, C. H. Seo, K. Han, K. W. Kwon, A. Levchenko, and K. Y. Suh, “Guided Cell Migration on Microtextured Substrates with Variable Local Density and Anisotropy,” Adv. Funct. Mater., Vol.19, pp. 1579-1586, 2009.
-  K. M. Davis, K. Miura, N. Sugimoto, and K. Hirao, “Writing waveguides in glass with a femtosecond laser,” Opt. Lett., Vol.21, pp. 1729-1731, 1996.
-  E. N. Glezer, M. Milosavljevic, L. Huang, R. J. Finlay, T. H. Her, J. P. Callan, and E. Mazur, “Three-dimensional optical storage inside transparent materials,” Opt. Lett., Vol.21, pp. 2023-2025, 1996.
-  Y. Hanada, K. Sugioka, H. Kawano, I. S. Ishikawa, A. Miyawaki, and K. Midorikawa, “Nano-aquarium for dynamic observation of living cells fabricated by femtosecond laser direct writing of photostructurable glass,” Biomed. Microdevices, Vol.10, No.3, pp. 403-410, 2008.
-  K. Sugioka, Y. Hanada, and K. Midorikawa, “Three-dimensional femtosecond laser micromachining of photosensitive glass for biomicrochips,” Laser Photonics Rev., Vol.4, No.3, pp. 386-400, 2010.
-  Y. Hanada, K. Sugioka, I. S. Ishikawa, H. Kawano, A. Miyawaki, and K. Midorikawa, “3D microfluidic chips with integrated functional microelements fabricated bya femtosecond laser for studying the gliding mechanism of cyanobacteria,” Lab Chip, Vol.11, pp. 2109-2115, 2011.
-  Y. Hanada, T. Ogawa, K. Koike, and K. Sugioka, “Making the invisible visible: a microfluidic chip using a low refractive index polymer,” Lab Chip, Vol.16, pp. 2481-2486, 2016.
-  D. Choudhury, W. T. Ramsay, R. Kiss, N. A. Willoughby, L. Paterson, and A. K. Kar, “A 3D mammalian cell separator biochip,” Lab Chip, Vol.12, pp. 948-953, 2012.
-  A. Schaap, Y. Bellouard, and T. Rohrlack, “Optofluidic lab-on-a-chip for rapid algae population screening,” Biomed. Opt. Express, Vol.2, pp. 658-664, 2011.
-  T. Arai, “Tchnical Review of Laser Materials Processing in Japan,” Int. J. of Automation Technol., Vol.10, No.6, pp. 854-862, 2016.
-  D. Homoelle, S. Wielandy, A. L. Gaeta, N. F. Borrelli, and C. Smith, “Infrared photosensitivity in silica glasses exposed to femtosecond laser pulses,” Opt. Lett., Vol.24, No.18, pp. 1311-1313, 1999.
-  A. Zoubir, M. Richardson, L. Canioni, A. Brocas, and L. Sarger, “Optical properties of infrared femtosecond laser-modified fused silica and application to waveguide fabrication,” J. Opt. Soc. Am. B, Vol.22, No.10, pp. 2138-2143, 2005.