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A versatile snap chip for high-density sub-nanoliter chip-to-chip reagent transfer.

Li H, Munzar JD, Ng A, Juncker D - Sci Rep (2015)

Bottom Line: Misalignment, which for direct transfer ranged from 150-250 μm, was reduced to <40 μm for double transfer.The versatility of the snap chip is illustrated with a 4-plex homogenous enzyme inhibition assay analyzing 128 conditions with precise timing.The versatility and high density of the snap chip with double transfer allows for the development of high throughput reagent transfer protocols compatible with a variety of applications.

View Article: PubMed Central - PubMed

Affiliation: 1] Biomedical Engineering Department, McGill University, Montréal, QC, H3A 0G1, Canada [2] McGill University and Genome Quebec Innovation Centre, McGill University, Montréal, QC, H3A 0G1, Canada.

ABSTRACT
The coordinated delivery of minute amounts of different reagents is important for microfluidics and microarrays, but is dependent on advanced equipment such as microarrayers. Previously, we developed the snap chip for the direct transfer of reagents, thus realizing fluidic operations by only manipulating microscope slides. However, owing to the misalignment between arrays spotted on different slides, millimeter spacing was needed between spots and the array density was limited. In this work, we have developed a novel double transfer method and have transferred 625 spots cm(-2), corresponding to >10000 spots for a standard microscope slide. A user-friendly snapping system was manufactured to make liquid handling straightforward. Misalignment, which for direct transfer ranged from 150-250 μm, was reduced to <40 μm for double transfer. The snap chip was used to quantify 50 proteins in 16 samples simultaneously, yielding limits of detection in the pg/mL range for 35 proteins. The versatility of the snap chip is illustrated with a 4-plex homogenous enzyme inhibition assay analyzing 128 conditions with precise timing. The versatility and high density of the snap chip with double transfer allows for the development of high throughput reagent transfer protocols compatible with a variety of applications.

No MeSH data available.


Related in: MedlinePlus

Photographs of the polymer snap apparatus.(a) Opened apparatus with a nitrocellulose assay slide and a 25 μm kapton polyimide film spacer placed around the 12 μm thick nitrocellulose pads (left) and an aminosilane transfer slide (right) in the chuck. A white silicone rubber cushion, visible behind both slides, allows pressure to be distributed evenly over the slide surface. A rubber corner is used in each chuck to secure the slide by pressing it against the opposite corner. (b) Photograph of a closed snap apparatus fastened with four screws.
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f1: Photographs of the polymer snap apparatus.(a) Opened apparatus with a nitrocellulose assay slide and a 25 μm kapton polyimide film spacer placed around the 12 μm thick nitrocellulose pads (left) and an aminosilane transfer slide (right) in the chuck. A white silicone rubber cushion, visible behind both slides, allows pressure to be distributed evenly over the slide surface. A rubber corner is used in each chuck to secure the slide by pressing it against the opposite corner. (b) Photograph of a closed snap apparatus fastened with four screws.

Mentions: The snapping of two slides with microscale features requires a dedicated apparatus with high alignment accuracy. We previously introduced an apparatus made of aluminum12. Although functional, this apparatus weighed 4.2 kg and required an on-site vacuum source to hold the slides in place, making it somewhat cumbersome to use. Here, we demonstrate a polymer snap apparatus that is more portable and user-friendly. The apparatus was machined out of polyoxymethylene, which has a high stiffness at room temperature and is often used for fabricating precision parts22. The polymeric snap apparatus weighs only 232 g and has a benchtop footprint of 9.8 × 5.5 cm2, as shown in Fig. 1. Two rods placed at opposing corners guide the slides together during snapping. Each slide is locked in place by a disposable rubber corner. The rubber corner is thinner than the microarray slide, such that it does not interfere with the snapping process. A thin silicone rubber cushion is then inserted between each slide and the apparatus, allowing for pressure to be evenly distributed over the slide surface during snapping. Finally, a constant gap between the slides is ensured by using a gasket spacer with a thickness chosen depending on the application, which is inserted between the two slides prior to snapping. The two halves of the apparatus are then snapped and held together by fastening screws, as shown in Fig. 1b, and reagent droplets from the transfer slide contact the assay slide. The use of a thin silicone rubber film and a spacer mitigated variations from operator-to-operator, and avoided the over-compression of droplets between slides. This improved polymer-based snap apparatus is simple-to-use and yields precise alignment.


A versatile snap chip for high-density sub-nanoliter chip-to-chip reagent transfer.

Li H, Munzar JD, Ng A, Juncker D - Sci Rep (2015)

Photographs of the polymer snap apparatus.(a) Opened apparatus with a nitrocellulose assay slide and a 25 μm kapton polyimide film spacer placed around the 12 μm thick nitrocellulose pads (left) and an aminosilane transfer slide (right) in the chuck. A white silicone rubber cushion, visible behind both slides, allows pressure to be distributed evenly over the slide surface. A rubber corner is used in each chuck to secure the slide by pressing it against the opposite corner. (b) Photograph of a closed snap apparatus fastened with four screws.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493572&req=5

f1: Photographs of the polymer snap apparatus.(a) Opened apparatus with a nitrocellulose assay slide and a 25 μm kapton polyimide film spacer placed around the 12 μm thick nitrocellulose pads (left) and an aminosilane transfer slide (right) in the chuck. A white silicone rubber cushion, visible behind both slides, allows pressure to be distributed evenly over the slide surface. A rubber corner is used in each chuck to secure the slide by pressing it against the opposite corner. (b) Photograph of a closed snap apparatus fastened with four screws.
Mentions: The snapping of two slides with microscale features requires a dedicated apparatus with high alignment accuracy. We previously introduced an apparatus made of aluminum12. Although functional, this apparatus weighed 4.2 kg and required an on-site vacuum source to hold the slides in place, making it somewhat cumbersome to use. Here, we demonstrate a polymer snap apparatus that is more portable and user-friendly. The apparatus was machined out of polyoxymethylene, which has a high stiffness at room temperature and is often used for fabricating precision parts22. The polymeric snap apparatus weighs only 232 g and has a benchtop footprint of 9.8 × 5.5 cm2, as shown in Fig. 1. Two rods placed at opposing corners guide the slides together during snapping. Each slide is locked in place by a disposable rubber corner. The rubber corner is thinner than the microarray slide, such that it does not interfere with the snapping process. A thin silicone rubber cushion is then inserted between each slide and the apparatus, allowing for pressure to be evenly distributed over the slide surface during snapping. Finally, a constant gap between the slides is ensured by using a gasket spacer with a thickness chosen depending on the application, which is inserted between the two slides prior to snapping. The two halves of the apparatus are then snapped and held together by fastening screws, as shown in Fig. 1b, and reagent droplets from the transfer slide contact the assay slide. The use of a thin silicone rubber film and a spacer mitigated variations from operator-to-operator, and avoided the over-compression of droplets between slides. This improved polymer-based snap apparatus is simple-to-use and yields precise alignment.

Bottom Line: Misalignment, which for direct transfer ranged from 150-250 μm, was reduced to <40 μm for double transfer.The versatility of the snap chip is illustrated with a 4-plex homogenous enzyme inhibition assay analyzing 128 conditions with precise timing.The versatility and high density of the snap chip with double transfer allows for the development of high throughput reagent transfer protocols compatible with a variety of applications.

View Article: PubMed Central - PubMed

Affiliation: 1] Biomedical Engineering Department, McGill University, Montréal, QC, H3A 0G1, Canada [2] McGill University and Genome Quebec Innovation Centre, McGill University, Montréal, QC, H3A 0G1, Canada.

ABSTRACT
The coordinated delivery of minute amounts of different reagents is important for microfluidics and microarrays, but is dependent on advanced equipment such as microarrayers. Previously, we developed the snap chip for the direct transfer of reagents, thus realizing fluidic operations by only manipulating microscope slides. However, owing to the misalignment between arrays spotted on different slides, millimeter spacing was needed between spots and the array density was limited. In this work, we have developed a novel double transfer method and have transferred 625 spots cm(-2), corresponding to >10000 spots for a standard microscope slide. A user-friendly snapping system was manufactured to make liquid handling straightforward. Misalignment, which for direct transfer ranged from 150-250 μm, was reduced to <40 μm for double transfer. The snap chip was used to quantify 50 proteins in 16 samples simultaneously, yielding limits of detection in the pg/mL range for 35 proteins. The versatility of the snap chip is illustrated with a 4-plex homogenous enzyme inhibition assay analyzing 128 conditions with precise timing. The versatility and high density of the snap chip with double transfer allows for the development of high throughput reagent transfer protocols compatible with a variety of applications.

No MeSH data available.


Related in: MedlinePlus