Method of preparing test samples
A method of preparing a sample may include depositing an aqueous solution comprising copies of a primer into a layer of hydrophobic liquid on a substrate with a thermal inkjet device. A sample may include: a substrate; a layer of hydrophobic liquid on the substrate, the layer of hydrophobic liquid comprising a plurality of droplets of aqueous solution distributed in the layer, wherein the plurality of droplets contain: primers; a polymerase enzyme; deoxynucleotide triphosphates (dNTPs); and a target sequence for replication; and a cover, the cover contacting and covering the layer of hydrophobic liquid.
1. A method of preparing a sample, the method comprising:
removing a cover from a substrate to expose a first layer of hydrophobic liquid on the substrate, wherein the cover comprises a second layer of the hydrophobic liquid;
depositing, with a thermal inkjet printhead, droplets of an aqueous solution comprising copies of a primer into the first layer of hydrophobic liquid on the substrate; and
replacing the cover over the substrate to form a single layer of the hydrophobic liquid as the first layer and the second layer contact one another and suspending the droplets in the single layer.
2. The method of claim 1 , further comprising:
depositing the aqueous solution to form a pattern of droplets of aqueous solution within the first layer of hydrophobic liquid.
3. The method of claim 2 , wherein the droplets of aqueous solution are uniform in size.
4. The method of claim 2 , wherein the droplets of aqueous solution comprise a first group of droplets with a first uniform size and a second group of droplets with a second uniform size.
5. The method of claim 2 , wherein a droplet of aqueous solution within the first layer of hydrophobic liquid is formed using multiple firings by the thermal inkjet printhead.
6. The method of claim 2 , further comprising measuring a property of the droplets in the pattern of droplets.
7. The method of claim 6 , wherein measuring a property of the droplets in the pattern of droplets is performed simultaneously on a plurality of droplets.
8. The method of claim 1 , wherein the hydrophobic liquid is a mineral oil.
9. The method of claim 1 , wherein the aqueous solution further comprises a master mix and a deoxyribonucleic acid (DNA) fragment.
10. The method of claim 1 , wherein the aqueous solution further comprises a master mix and a ribonucleic acid (RNA) fragment.
11. The method of claim 1 , further comprising performing a polymerase chain reaction (PCR) to amplify a target in a droplet of the aqueous solution.
12. The method of claim 1 , wherein the substrate comprises dividers to separate areas for droplet deposition and to provide a contact point for the cover.
13. The method of claim 1 , wherein:
the cover is a thermally conductive cover; and
the substrate is a thermally conductive substrate.
14. The method of claim 1 , further comprising aligning, with alignment features on the substrate and a platen of an ejection system comprising the thermal inkjet printhead, ejectors of the thermal inkjet printhead to a location on the substrate.
15. The method of claim 1 , wherein depositing an aqueous droplet comprises dispensing multiple droplets at a single location, each droplet being of a different compound to execute polymerase chain reaction.
16. The method of claim 1 , further comprising encoding information in the sample by forming droplets in a pattern.
17. The method of claim 1 , further comprising encoding an identification of the sample by forming droplets in a pattern of alphanumeric characters.