Prototyping of microfluidic systems using a commercial thermoplastic elastomer

Abstract

This article describes the fabrication of microfluidic networks (lFNs) from a commercially available (styrene)-(ethylene/butylene)-(styrene) (SEBS) block copolymer (BCP). The unique combination of hard and elastomeric properties provided by this material promotes high-throughput replication of fluidic structures using thermoforming technologies, while retaining the advantage of quick and easy assembly via conformal contact, as commonly achieved for devices fabricated from poly(dimethylsiloxane (PDMS). We employ Versaflex CL30, which is optically transparent, available at low cost (e.g., $2.50/Lbs), and likely to be compatible with a broad range of biological species. We demonstrate excellent fidelity in replication of fluidic structures using hot embossing lithography in conjunction with a photolithographically prepared Si/SU-8 master mold. Moreover, we introduce rapid prototyping of high-quality structures using an approach that we call soft thermoplastic lithography (STPL). Thanks to the rheological characteristics of the SEBS copolymer, STPL enables thermoforming on a heated master at temperatures around 170°C. Using this approach, replication can be completed within a very short period of time (e.g., less than 3 min) without the need of resorting to pressure-or vacuum-assisted instrumentation. Serving as a proof-of-concept, we devise a lFN that is suitable for the formation of miniaturized arrays comprising fluorescently labeled oligonucleotides and proteins on hard plastic substrates. Resultant spots are characterized by high fluorescent contrast, excellent edge definition, and uniform distribution of probes within the modified areas.

Assessment of multidrug resistance on cell coculture patterns using scanning electrochemical microscopy

“…We use an open through-hole membrane fabricated from an elastomeric blockcopolymer (e.g., Versaflex CL30, GLS Corp.) (37) (see SI Text for details) in combination with oxygen plasma treatment to achieve live cell patterns on an insulating plastic substrate (e.g., Zeonor 1060R, Zeon Chemicals). Versaflex CL30 is a meltprocessable styrenic ethylene/butylene block-copolymer (38,39) which has recently been shown to promote the fabrication of thin-film membranes with small-scale openings in a single step using hot embossing lithography (HEL) (37). In principle, open through-hole membranes can be produced from other elastomers such as poly(dimethylsiloxane) (PDMS), which to this end constitutes the prime material for soft microfabrication and patterning (35,36).…”

Rapid isothermal substrate microfabrication of a biocompatible thermoplastic elastomer for cellular contact guidance

“…SEBS co-polymers also have great transparency, more than 85% transmission throughout the entire 400-800 nm visible spectrum. This transparency can be explained by the fact that styrene domains, varying between 10 and 25 nm, are too small to scatter light [34]. These properties are important for cell evaluation during the culture period and also allow direct staining of cells and tissues while on the SEBS samples.…”

3D thermoplastic elastomer microfluidic devices for biological probe immobilization

“…We have recently identified commercially available thermoplastic 45 elastomers (TPE) that can adapt to other surfaces through conformal contact in a similar way than PDMS, while providing the appealing ability to be processed using conventional thermoforming methods such as hot embossing lithography (HEL) or injection molding. 29,53,55,56 In this 50 paper, we extend this work by demonstrating the rapid and reliable patterning of open through-holes and channels in thin TPE membranes using a method based on HEL. We then discuss the design of a TPE-based 3D microfluidic patterning device that permits the immobilization of up to 96 different 55 biological probes in a 10 × 10 array format of 50 × 50 m 2 spots.…”

“…Finally, if required, 25 permanent bonding of two TPE membranes can be achieved conveniently by exposing them to elevated temperature after alignment. 53 For PDMS, O 2 plasma treatment needs to be performed immediately before aligning the membranes and pressing them together. 36,54 30 …”