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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

Schematic illustrating the process flow for snap chip fabrication using a double transfer protocol, as used for carrying out multiplexed biochemical assays.(a) Reagent 1 is spotted on transfer slide 1 and (b) transferred to the assay slide by snapping, (c) yielding a microarray of reagent 1 on the assay slide. (d) Reagent 2 is spotted on transfer slide 2 using an inkjet microarray spotter. (e) Both the assay slide and transfer slide 2 are stored for later use. (f) Prior to performing the assay, both slides are retrieved, and (g) the assay slide is incubated with a sample if necessary, then washed and dried. (h) The assay slide and transfer slide 2 are snapped together to transfer reagent 2 to the assay slide. Following rinsing, (i) the assay slide is incubated with fluorescent dyes, if necessary, and after another rinse, dried, and (j) the assay results are read out.
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f2: Schematic illustrating the process flow for snap chip fabrication using a double transfer protocol, as used for carrying out multiplexed biochemical assays.(a) Reagent 1 is spotted on transfer slide 1 and (b) transferred to the assay slide by snapping, (c) yielding a microarray of reagent 1 on the assay slide. (d) Reagent 2 is spotted on transfer slide 2 using an inkjet microarray spotter. (e) Both the assay slide and transfer slide 2 are stored for later use. (f) Prior to performing the assay, both slides are retrieved, and (g) the assay slide is incubated with a sample if necessary, then washed and dried. (h) The assay slide and transfer slide 2 are snapped together to transfer reagent 2 to the assay slide. Following rinsing, (i) the assay slide is incubated with fluorescent dyes, if necessary, and after another rinse, dried, and (j) the assay results are read out.

Mentions: In this work, we have developed a novel double transfer method that is an improvement to the direct transfer process which we described previously12. The main difference between this protocol and the previous direct transfer technique is that here both reagent arrays are transferred onto the final assay slide. Previously, the first reagent (e.g. cAb) was directly spotted on the assay slide, while the second reagent (e.g. dAb) was spotted on the transfer slide in a mirror image configuration of the first reagent. The transfer slide was then directly interfaced with the assay slide. In the double transfer process, the first and the second reagents are spotted sequentially on two separate transfer slides with an inkjet spotter using the same spotting layout, such that both slides contained reagents patterned in the same layout and spotted at the same location on the spotter deck. Next, the microarray of reagent 1 is transferred to an empty assay slide using the snap apparatus. Finally, the microarray of reagent 2 (transferred spots) is interfaced with the assay slide (which comprises an array of sessile spots) using the snap apparatus. By aligning the two transfer slides to the same location on the inkjet spotter deck and to the same corner of the snap chip apparatus, the two reagents are consistently delivered to their respective positions on the assay slide. While it is possible to solve the misalignment problem by calibrating the inkjet spotter, it is in practice very difficult and cumbersome to do so due to regular day-to-day drift of the gantry system on the spotter which requires recalibration after each system initialization and after re-installation of the nozzle. Also, the double transfer method circumvents the need for a fiducial marker and camera recognition system compared to the direct transfer process; it also addresses angular misalignment as described in detail below. The process flow of the double transfer protocol, including fabrication of the snap chip, is illustrated in Fig. 2a–e.


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)

Schematic illustrating the process flow for snap chip fabrication using a double transfer protocol, as used for carrying out multiplexed biochemical assays.(a) Reagent 1 is spotted on transfer slide 1 and (b) transferred to the assay slide by snapping, (c) yielding a microarray of reagent 1 on the assay slide. (d) Reagent 2 is spotted on transfer slide 2 using an inkjet microarray spotter. (e) Both the assay slide and transfer slide 2 are stored for later use. (f) Prior to performing the assay, both slides are retrieved, and (g) the assay slide is incubated with a sample if necessary, then washed and dried. (h) The assay slide and transfer slide 2 are snapped together to transfer reagent 2 to the assay slide. Following rinsing, (i) the assay slide is incubated with fluorescent dyes, if necessary, and after another rinse, dried, and (j) the assay results are read out.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Schematic illustrating the process flow for snap chip fabrication using a double transfer protocol, as used for carrying out multiplexed biochemical assays.(a) Reagent 1 is spotted on transfer slide 1 and (b) transferred to the assay slide by snapping, (c) yielding a microarray of reagent 1 on the assay slide. (d) Reagent 2 is spotted on transfer slide 2 using an inkjet microarray spotter. (e) Both the assay slide and transfer slide 2 are stored for later use. (f) Prior to performing the assay, both slides are retrieved, and (g) the assay slide is incubated with a sample if necessary, then washed and dried. (h) The assay slide and transfer slide 2 are snapped together to transfer reagent 2 to the assay slide. Following rinsing, (i) the assay slide is incubated with fluorescent dyes, if necessary, and after another rinse, dried, and (j) the assay results are read out.
Mentions: In this work, we have developed a novel double transfer method that is an improvement to the direct transfer process which we described previously12. The main difference between this protocol and the previous direct transfer technique is that here both reagent arrays are transferred onto the final assay slide. Previously, the first reagent (e.g. cAb) was directly spotted on the assay slide, while the second reagent (e.g. dAb) was spotted on the transfer slide in a mirror image configuration of the first reagent. The transfer slide was then directly interfaced with the assay slide. In the double transfer process, the first and the second reagents are spotted sequentially on two separate transfer slides with an inkjet spotter using the same spotting layout, such that both slides contained reagents patterned in the same layout and spotted at the same location on the spotter deck. Next, the microarray of reagent 1 is transferred to an empty assay slide using the snap apparatus. Finally, the microarray of reagent 2 (transferred spots) is interfaced with the assay slide (which comprises an array of sessile spots) using the snap apparatus. By aligning the two transfer slides to the same location on the inkjet spotter deck and to the same corner of the snap chip apparatus, the two reagents are consistently delivered to their respective positions on the assay slide. While it is possible to solve the misalignment problem by calibrating the inkjet spotter, it is in practice very difficult and cumbersome to do so due to regular day-to-day drift of the gantry system on the spotter which requires recalibration after each system initialization and after re-installation of the nozzle. Also, the double transfer method circumvents the need for a fiducial marker and camera recognition system compared to the direct transfer process; it also addresses angular misalignment as described in detail below. The process flow of the double transfer protocol, including fabrication of the snap chip, is illustrated in Fig. 2a–e.

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