Microfluidics in silicon/polymer technology as a cost-efficient alternative to silicon/glass

Abstract

We investigate TMMF photopolymer as a cost-efficient alternative to glass for the leak-tight sealing of high-density silicon microchannels. TMMF enables low temperature sealing and access to structures underneath via lamination and standard UV-lithography instead of costly glass machining and anodic bonding. TMMF is highly transparent and has a low autofluorescence for wavelengths larger than 400 nm. As the photopolymer is too thin for implementing bulky world-to-chip interfaces, we propose adhesive bonding of cyclic olefin copolymer (COC) modules. All materials were tested according ISO 10993-5 and showed no cytotoxic effects on the proliferation of L929 cells. To quantify the cost efficiency of the proposed techniques, we used an established silicon/Pyrex nanoliter dispenser as a reference and replaced structured Pyrex wafers by TMMF laminates and COC modules. Thus, consumable costs, manpower and machine time related to sealing of the microchannels and implementing the world-to-chip interface could be significantly reduced. Leak tightness was proved by applying a pressure of 0.2 MPa for 5 h without delamination or crosstalk between neighboring microchannels located only 100 μm apart. In contrast to anodic bonding, the proposed techniques are tolerant to surface inhomogeneities. They enable manufacturing of silicon/polymer microfluidics at lower costs and without compromising the performance compared to corresponding silicon/glass devices.

Lab-on-a-chip devices: How to close and plug the lab?

“…As a notable example for rapid prototyping using DFRs, Zhao et al introduced a process, ''do it yourself 3D microfluidic chips'', which is based on multilayer lamination of DFRs and patterning them by direct projection lithography using a commercially available digital projector [127]. More recently, different types of DFRs were used by several research groups for various biosensing applications [128][129][130]. Companies, such as DuPont (USA) [131], Engineered Materials Systems (USA) [132], Elga Europe (Italy) [133], Tokyo Ohka Kogyo Co. (Japan) [134], DJ DevCorp (USA) [135], are producing DFRs having thicknesses ranging from 5 lm to 1000 lm and in the form of sheets or rolls (up to 100 m long).…”

Applications of Microfluidics in Stem Cell Biology

“…Prepare the substrate. Silicon with different types of doping is most commonly used substrate [15,16]. But other types of substrate can also easily be made on silicon wafers, like silicon dioxide, silicon nitride, depending on the applications.…”

Micro-ultrasonic welding using thermoplastic-elastomeric composite film

“…Becker and Locascio (2002) reviewed other materials including polymethyl methacrylate (PMMA) and polydimethylsiloxane (PDMS) which are commonly preferred in industries as cheaper alternatives to glass. Kalkandjiev et al (2011) highlighted the low fabrication cost and the ease to mass produce as the major reasons of using PDMS and PMMA, and Luo et al (2010) demonstrated that the PMMA also have the potential to create complex, stable geometries using simple fabrication methods (without fabricating energy directors), while being able to accommodate errors in terms of reversible change upon softening and melting.…”