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PicoFill-SystemsOutlicensing Electrospray Deposition onto Small Targets

Target Businesses: MicroArray Applications: Spraying of enzymes, metabolites, co-factors, yeast cells, antibodies

Dotting of Microliter & Nanoliter Fractions onto MALDI targets

Coating Industry: spraying of liquids containing metal particles, plastics, etching or curing agents, etc.

Spraying requirements: Low – high conductive surfaces: silicon nitride, metal, metal coated

plastics (10 nm thick metal layer)

Liquid surface tension < 0.05 N/m

Capillary material: any low – high conductive material 0.4 millimeter

Dot

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Spraying Set-Up: assembled standard devices

Upon execution of the desired x-y-z data, a substrate is moved underneath a capillary at high precision while liquid is sprayed onto the substrate at controlled flow rates of picoliters–nanoliters per second.

Harvard PumpHigh Precision

Power Supply

Microscope, CCD-camera

x-y-z stage

Syringe-capillary

Computer controlledMotion controller:

Sends x-y-z data to the x-y-z table

MicroArray

Syringe-capillary

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Spraying Parameters

Dot Size• Dot size is related to the distance between the capillary-tip and the substrate (spraying distance)• Dot size is related to the capillary outer diameter: the smaller the outer diameter, the smaller the

cone size• Dot size is related to the flow rate: at low flow rates the liquid evaporates rapidly resulting in a

solid dot instead of a donut like dot. • Typical dot sizes for a capillary-OD of 150 micron and flow rates of 100–400 picoliter/second :

150–400 microns at spraying distances of 250–500 micron, respectively

MicroArray Applications• Flow rates: picoliters-nanoliters/second• Distance between capillary-tip and substrate (spraying distance): 200–500 micron • Dot size microarray: 100–400 micron at spraying distances of 200–500 micron• Preferred capillary outer diameter: 50–200 micron• Maximum speed of x-y-z table depends on actuators

Dotting of fractions onto MALDI plate targets• Flow rates: 1 nanoliter/second – 0.6 microliter/second • Dot sizes: 400–1500 micron at spraying distances of 500–2000 micron, respectively

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Spraying of Arrays of Dots

1-2 kVSpray of droplets

MicroArray or slide

1–2 kV

Spot

A. Piston pushes liquid through syringe while electric field is applied

Slide is moved downward and sideways: typical 200 – 1000 micron

Second spot is sprayed onto slide

B. Slide is moved downward to lower the electric field: spraying stops

C. Slide is moved upward and spraying resumes

1-2 kV

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Parallel Spraying

Spots: 0.6 millimeter apart