A multi-scale PDMS fabrication strategy to bridge the size mismatch between integrated circuits and microfluidics
Year: 2014
Type: article
Abstract: In recent years there has been great progress harnessing the small-feature size and programmability of integrated circuits (ICs) for biological applications, by building microfluidics directly on top of ICs. However, a major hurdle to the further development of this technology is the inherent size-mismatch between ICs (~mm) and microfluidic chips (~cm). Increasing the area of the ICs to match the size of the microfluidic chip, as has often been done in previous studies, leads to a waste of valuable space on the IC and an increase in fabrication cost (>100×). To address this challenge, we have developed a three dimensional PDMS chip that can straddle multiple length scales of hybrid IC/microfluidic chips. This approach allows millimeter-scale ICs, with no post-processing, to be integrated into a centimeter-sized PDMS chip. To fabricate this PDMS chip we use a combination of soft-lithography and laser micromachining. Soft lithography was used to define micrometer-scale fluid channels directly on the surface of the IC, allowing fluid to be controlled with high accuracy and brought into close proximity to sensors for highly sensitive measurements. Laser micromachining was used to create ~50 μm vias to connect these molded PDMS channels to a larger PDMS chip, which can connect multiple ICs and house fluid connections to the outside world. To demonstrate the utility of this approach, we built and demonstrated an in-flow magnetic cytometer that consisted of a 5 × 5 cm(2) microfluidic chip that incorporated a commercial 565 × 1145 μm(2) IC with a GMR sensing circuit. We additionally demonstrated the modularity of this approach by building a chip that incorporated two of these GMR chips connected in series.
Source: Lab on a Chip
DOI: 10.1039/c4lc00869c
Authors: Melaku Muluneh, David Issadore
Institution: University of Pennsylvania
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, University of Pennsylvania, Directorate for Biological Sciences, Center for AIDS Research, University of Washington, National Cancer Institute, National Institute of Allergy and Infectious Diseases, Division of Materials Research
OpenAlex ID: W1991272343