title: Ship-in-a-bottle femtosecond laser integration of optofluidic microlens arrays with center-pass units enabling coupling-free parallel cell counting with a 100% success rate.
abstract: Optimal design and fabrication of novel devices for high-performance optofluidic applications is a key issue for the development of advanced lab-on-a-chip systems. Parallel cell counting with a high success rate and simple mode of operation is a challenging goal. Current cell-counting methods, using optical waveguides or flow cytometry, typically require a precise coupling of the probe light and involve complex operations. In the present paper, a novel multifunctional cell counting microdevice is designed. It uses a center-pass optofluidic microlens array (MLA) consisting of seven microlenses and an M-shaped confining wall with 9 μm-diameter apertures. The device can be fabricated in a three-dimensional microchannel by ship-in-a-bottle femtosecond laser integration based on two-photon polymerization with optimized experimental parameters. Each microlens produces approximately the same intensity at the focal positions (within ±5%) under white-light illumination, while the confining wall restricts 6∼8 μm-width cells to passing through the edges of two adjacent microlenses because the aperture opens toward their centers. The device demonstrates coupling-free parallel cell counting with a 100% success rate by monitoring the optical intensity variations at each spot. As a result, this method features both easy operation and high performance. Furthermore, the confining wall can filter deformed cells having 15 μm width.
authors.affiliation: Laser Technology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. ksugioka@riken.jp.
authors.forename: Dong
authors.initials: D
authors.lastname: Wu
authors.forename: Li-Gang
authors.initials: LG
authors.lastname: Niu
authors.forename: Si-Zhu
authors.initials: SZ
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Katsumi
authors.initials: K
authors.lastname: Midorikawa
authors.forename: Koji
authors.initials: K
authors.lastname: Sugioka
mesh_terms: D002452:Cell Count / Q000295:instrumentation*; D004867:Equipment Design; D005898:Glass; D007834:Lasers; D007909:Lenses; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D018511:Systems Integration