1 PicoFill-Systems Outlicensing 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

2 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 Pump High Precision Power Supply Microscope, CCD-camera x-y-z stage Syringe-capillary Computer controlled Motion controller: Sends x-y-z data to the x-y-z table MicroArray Syringe-capillary

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 1-2 kV Spray 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

5 Parallel Spraying Spots: 0.6 millimeter apart