Glass microprism matrix for fluorescence excitation in lab-on-a-chip platforms

Abstract

In this paper, an integrated microprism matrix for light coupling and optical sensing systems is presented. The matrix was fabricated by use of controlled negative pressure glass thermal reflow process by the use of monocrystalline mold. The single glass microprism had height of 250 µm or 350 µm with base width respectively 350 µm or 500 µm. The matrix was formed by 10 × 10 microprisms with distance between the microprisms from 150 µm to 400 µm. It corresponded to total area of the matrixes from 28 mm2 to 74 mm2. The controlled coupling of the beam into a substrate was obtained through determination of optimal geometric dimensions of microprisms and configuration of a measurement setup. Optimal position of the fluorescence induction light source in relation to the matrixes (0.5 cm to 4.5 cm distance, 30° angle of incidence) and microfluidic channel (4 mm) were determined. The fluorimetric tests (with excitation by 470 nm laser diode in all the experiments) carried out using fluorescein solution, microbeads and porcine oocyte indicated the possibility of using a microprism matrix for fluorimetric image-based 500 nm long-pass detection in lab-on-a-chip platforms.

Transillumination lab-on-a-chip cytometer with silicon/glass membrane for image-based porcine oocyte deformation characterisation

“…Next, vacuum (∼10 −3 mbar) anodic bonding of a 0.5 mm thick borosilicate glass substrate (Borofloat 3.3, Schott, Germany; 450 • C, 2 kV) and a previously micromachined silicon substrate was carried out. In the next step, glass reflow (800 • C, 1 h) was carried out according to a previous procedure optimised by us for the fabrication of glass microlenses or prisms [21,22]. Next, the redundant glass layer was removed (mechanically polished) from the top side of the thick membrane.…”