Hard Top Soft Bottom Microfluidic Devices for Cell Culture and Chemical Analysis

Abstract

We report fabrication and characterization of microfluidic devices made of thermoplastic and elastomeric polymers. These hard-soft hybrid material devices are motivated by the combined need for large scale manufacturability, enhanced barrier properties to gas permeation and evaporation of aqueous solutions compared to poly(dimethyl siloxane) (PDMS) devices, and compatibility with deformation-based actuation. Channel features are created on rigid polymers such as polyethylene terephthalate glycol (PETG), cyclic olefin copolymer (COC), and polystyrene (PS) by hot embossing. These "hard tops" are bonded to elastomeric "soft bottoms" (polyurethane (PU) or PDMS-parylene C-PDMS) to create devices that can be used for microfluidic cell culture where deformation-based fluid actuation schemes are used to perfuse and recirculate media. The higher barrier properties of this device compared to PDMS devices enable cell culture with less evaporation and creation of hypoxic conditions.

Dependence of the quality of adhesion between poly(dimethylsiloxane) and glass surfaces on the composition of the oxidizing plasma

“…PDMS is a widely used material for fabricating lFDs (Gong and Wen 2009;Zhou et al 2010;Vullev et al 2006; Thomas et al 2010a). Despite its shortcomings, such as porosity (Li et al 2009;Mehta et al 2009;Chueh et al 2007;Shin et al 2003) and susceptibility to a broad range of organic solvents (Lee et al 2003), PDMS is biocompatible (Belanger and Marois 2001;Zhuang et al 2007) and allows for expedient and facile reproduction of features with nanometer precision that are essential for lFDs (Gates 2005;Cong and Pan 2008).…”

One step high quality poly(dimethylsiloxane)-hydrocarbon plastics bonding

“…However, they might not be a good candidate for ultrathin layer or multilayer chips since they are crispy and difficult to be processed. 2 In comparison, techniques for processing plastics boom in recent years and have increasingly been applied to microfluidics 3 and nanofluidics. 4 Plastics are advantageous not only because they are easier for processing or cheaper but also many of them are of high quality in terms of optical transparency, biochemical compatibility, electrical isolation, and/or resistance to the water for long term usage.…”

“…Many pioneer researchers have realized the potential value and have tried to achieve irreversible hybrid bonding by means of thin-adhesive layer, 5-7 chemical molecular level gluing, [8][9][10][11] or plasma treatment. 2 Detailed summarization of these techniques has been published in several papers. 11,12 The first two methods are formerly applied as alternative methods for thermal plastics bonding, where the original thermal bonding techniques usually require delicate pressure and temperature control with expertise.…”

“…1 However, further researches concluded that the bonding would delaminate upon extended periods of exposure to moisture. 2 By substituting part of the oxygen by inert gas argon, PDMS-COC/PS hybrid structures are successfully bonded. 2 The highest quality is 120 kPa for burst pressure, realized by 1:2 argonoxygen plasma with heating at 60 C and less than 1 lb pressure over night.…”

“…2 By substituting part of the oxygen by inert gas argon, PDMS-COC/PS hybrid structures are successfully bonded. 2 The highest quality is 120 kPa for burst pressure, realized by 1:2 argonoxygen plasma with heating at 60 C and less than 1 lb pressure over night. Although the bonding quality cannot meet the requirement for all the applications in microfluidics, it is valuable to point out that by applying a second kind of gas to the plasma system, the bonding quality for the substrates can be improved.…”