SPIE lezing

1
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 lt 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
picolitersnanoliters 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 100400 picoliter/second
  
• 150400 microns at spraying distances of 250500
  micron, respectively
• MicroArray Applications
• Flow rates picoliters-nanoliters/second
• Distance between capillary-tip and substrate
  (spraying distance) 200500 micron
• Dot size microarray 100400 micron at spraying
  distances of 200500 micron
• Preferred capillary outer diameter 50200
  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 4001500 micron at spraying distances
  of 5002000 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

12 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