One-Step Fabrication of Microchannels with Integrated Three Dimensional Features by Hot Intrusion Embossing

Abstract

We build on the concept of hot intrusion embossing to develop a one-step fabrication method for thermoplastic microfluidic channels containing integrated three-dimensional features. This was accomplished with simple, rapid-to-fabricate imprint templates containing microcavities that locally control the intrusion of heated thermoplastic based on their cross-sectional geometries. The use of circular, rectangular and triangular cavity geometries was demonstrated for the purposes of forming posts, multi-focal length microlense arrays, walls, steps, tapered features and three-dimensional serpentine microchannels. Process variables, such as temperature and pressure, controlled feature dimensions without affecting the overall microchannel geometry. The approach was demonstrated for polycarbonate, cycloolefin copolymer and polystyrene, but in principle is applicable to any thermoplastic. The approach is a step forward towards rapid fabrication of complex, robust, microfluidic platforms with integrated multi-functional elements.

A Review of Current Methods in Microfluidic Device Fabrication and Future Commercialization Prospects

“…One key limitation of hot embossing is the time consuming and expensive process of making molds. Using a unique modification of hot embossing known as hot intrusion embossing, Debono et al created a one-step process for the fabrication of microfluidic channels containing complex three-dimensional structures in various thermoplastics [38]. Their use of a rapid template mold fabrication method enabled molding of sub-50 µm tapered posts, steps, and walls, as well as three-dimensional serpentine channels.…”

A review on microwell and microfluidic geometric array fabrication techniques and its potential applications in cellular studies

“…The designed micromould is then pressed and heated to transfer the microfeatures onto the thin resist. After heating, the micromould is uplifted and desired features remained on the substrate surface [148] on the top and bottom of the channel using electrodes. The dielectrophoretic force can be approximated in terms of dipole effects as [181] :…”

“…The microwell formed using micro hot embossing fabrication technique is illustrated below in Figure 10. Recently, Debono et al [148] fabricated microchannels with integrated three-dimensional features while demonstrating a one-step method based on the concept of hot intrusion embossing (or partial embossing). These microchannels with integrated features such as semi-occluding walls can be utilized for cells/particles trapping.…”

Recent Advancements towards Full-System Microfluidics

“…Here they developed a new one-step fabrication method for creating three-dimensional features in thermoplastic microchannels using a photo-lithography based (2D) embossing stamp [ 20 ]. With a little-used variation to hot embossing, called hot intrusion embossing, or partial embossing [ 21 ] they could create thermoplastic microfluidic channels with integrated features with controllable dimensions. To showcase the approach as a one-step step method for rapid fabrication of complex, robust, microfluidic platforms with integrated multi-functional elements, a microfluidic device was fabricated with an integrated three-dimensional mixer and a multi-focal length lens array.…”