PicoFill-Systems Outlicensing Electrospray Deposition onto Small Targets

1. Dot 0.4 millimeter PicoFill-SystemsOutlicensing Electrospray Deposition onto Small Targets • 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 • 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.

2. Spraying Set-Up: assembled standard devices Syringe-capillary Harvard Pump High Precision Microscope, CCD-camera Computer controlled Motion controller: Sends x-y-z data to the x-y-z table Syringe-capillary Power Supply x-y-z stage MicroArray 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.

3. 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

4. Spraying of Arrays of Dots A. Piston pushes liquid through syringe while electric field is applied C. Slide is moved upward and spraying resumes B. Slide is moved downward to lower the electric field: spraying stops 1-2 kV 1–2 kV 1-2 kV Spray of droplets Second spot is sprayed onto slide MicroArray or slide Spot Slide is moved downward and sideways: typical 200 – 1000 micron

5. Parallel Spraying Spots: 0.6 millimeter apart