Lab-on-a-Foil: microfluidics on thin and flexible films

Abstract

This critical review is motivated by an increasing interest of the microfluidics community in developing complete Lab-on-a-Chip solutions based on thin and flexible films (Lab-on-a-Foil). Those implementations benefit from a broad range of fabrication methods that are partly adopted from well-established macroscale processes or are completely new and promising. In addition, thin and flexible foils enable various features like low thermal resistance for efficient thermocycling or integration of easily deformable chambers paving the way for new means of on-chip reagent storage or fluid transport. From an economical perspective, Lab-on-a-Foil systems are characterised by low material consumption and often low-cost materials which are attractive for cost-effective high-volume fabrication of self-contained disposable chips. The first part of this review focuses on available materials, fabrication processes and approaches for integration of microfluidic functions including liquid control and transport as well as storage and release of reagents. In the second part, an analysis of the state of Lab-on-a-Foil applications is provided with a special focus on nucleic acid analysis, immunoassays, cell-based assays and home care testing. We conclude that the Lab-on-a-Foil approach is very versatile and significantly expands the toolbox for the development of Lab-on-a-Chip solutions.

Fast and versatile fabrication of PMMA microchip electrophoretic devices by laser engraving

“…On the other extreme, techniques using paper and polyester-toner have been used to manufacture chips in less than 10 min with a cost lower than $ 0.10 per device, but the chemistry and topography of the materials often hinder the applicability of the technology [10,14,15]. Besides these examples, a range of polymers have emerged as alternative materials to fabricate ME devices [16][17][18][19]. In most cases, these plastics offer an adequate balance between fabrication procedures, cost, and analytical performance.…”

Microfluidic cryofixation for correlative microscopy

“…These points are addressed in the design by 1) minimizing the thermal mass of the channel containing the sample, 2) minimizing the distance between the cold surface and the sample, and 3) maintaining uninterrupted, room-temperature connections into and out of the heated microchannel. In particular, we found that microfluidic perfusion devices of extremely low thermal mass could be made using microfluidic polymer foils 14 in combination with silicon micromachined components. Microchannels embedded into PDMS foils only tens of micrometers thick were fabricated by a newly developed process and bonded to silicon fluidic chips, such that the embedded channel was suspended across a dry etched 1 mm circular aperture in the silicon.…”

Microfluidic Extreme PCR: <1 Minute DNA Amplification in a Thin Film Disposable

“…Channel dimensions are determined by film thickness and patterns cut out of the internal layers via the process of xurography, a low-cost and rapid approach to creating microstructures [11] [12].…”