| 1. |
- Elhami Nik, Farzad, et al.
(författare)
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Low-Cost PVD Shadow Masks with Submillimeter Resolution from Laser-Cut Paper
- 2020
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Ingår i: Micromachines. - Basel : MDPI. - 2072-666X. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- We characterize an affordable method of producing stencils for submillimeter physical vapor deposition (PVD) by using paper and a benchtop laser cutter. Patterning electrodes or similar features on top of organic or biological substrates is generally not possible using standard photolithography. Shadow masks, traditionally made of silicon-based membranes, circumvent the need for aggressive solvents but suffer from high costs. Here, we evaluate shadow masks fabricated by CO2 laser processing from quantitative filter papers. Such papers are stiff and dimensionally stable, resilient in handling, and cut without melting or redeposition. Using two exemplary interdigitated electrode designs, we quantify the line resolution achievable with both high-quality and standard lenses, as well as the positional accuracy across multiple length scales. Additionally, we assess the gap between such laser-cut paper masks and a substrate, and quantify feature reproduction onto polycarbonate membranes. We find that ~100 µm line widths are achievable independent of lens type and that average positional accuracy is better than ±100 µm at 4”-wafer scale. Although this falls well short of the micron-size features achievable with typical shadow masks, resolution in the tenths to tens of millimeters is entirely sufficient for applications from contact pads to electrochemical cells, allowing new functionalities on fragile materials.
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| 2. |
- Winkler, Thomas, Ph.D., et al.
(författare)
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Continuous monitoring of isogenic blood-brain barrier integrity in a pdms-free microphysiological system
- 2020
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Ingår i: MicroTAS 2020 - 24th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 963-964
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Konferensbidrag (refereegranskat)abstract
- We present a microphysiological system (MPS) of the human blood-brain barrier (BBB) that uniquely combines three key advantages - continuous monitoring, PDMS-free fabrication, and cellular relevance - over existing MPS, and we demonstrate BBB formation, breakdown, and rescue. Specifically, we model nitrosative stress - strongly implicated in brain-related disorders from stroke to Alzheimer's - and its prevention using a BBB-permeable antioxidant. This kind of MPS paves the way toward patient-specific BBB modeling for time-resolved studies of drug kinetics and/or side effects towards personalized treatment planning.
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| 3. |
- Winkler, Thomas, Ph.D., et al.
(författare)
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Low-cost microphysiological systems : feasibility study of a tape-based barrier-on-chip for small intestine modeling.
- 2020
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 20:7, s. 1212-1226
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Tidskriftsartikel (refereegranskat)abstract
- We see affordability as a key challenge in making organs-on-chips accessible to a wider range of users, particularly outside the highest-resource environments. Here, we present an approach to barrier-on-a-chip fabrication based on double-sided pressure-sensitive adhesive tape and off-the-shelf polycarbonate. Besides a low materials cost, common also to PDMS or thermoplastics, it requires minimal (€100) investment in laboratory equipment, yet at the same time is suitable for upscaling to industrial roll-to-roll manufacture. We evaluate our microphysiological system with an epithelial (Caco-2/BBe1) barrier model of the small intestine, studying the biological effects of permeable support pore size, as well as stimulation with a common food compound (chili pepper-derived capsaicinoids). The cells form tight and continuous barrier layers inside our systems, with comparable permeability but superior epithelial polarization compared to Transwell culture, in line with other perfused microphysiological models. Permeable support pore size is shown to weakly impact barrier layer integrity as well as the metabolic cell profile. Capsaicinoid response proves distinct between culture systems, but we show that impacted metabolic pathways are partly conserved, and that cytoskeletal changes align with previous studies. Overall, our tape-based microphysiological system proves to be a robust and reproducible approach to studying physiological barriers, in spite of its low cost.
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