Figure 1 shows a schematic view of a single functional spray unit of the nanoparticle generator. The capillary tips can be massed in precise configurations to produce high through-put operation.

 
Figure 2 (below) shows a magnified view of the capillary tip. On the left is the tip operating in pulsating mode and the meniscus of fluid is clearly visible. On the right is the tip operating in the cone jet mode where the electrical field forces the tip into the sharp point from which a nanofibril can be seen emerging from the tip. This fibril is unstable and breaks up into charged particles comprised of solvent carrier and active agent(s). The solvent evaporates due to the extremely high surface area.

 
Figure 3 shows uncoated nanoparticles of a model drug compound produced using ElectroNanoSpray™. Nanoparticle size distribution is extremely tight, here shown as 18.8±1.1 nm. Size is controllable by varying the process parameters.

 
Publications

1. Chen, D.R., C.H. Wendt and D.Y.H. Pui (2000). A novel approach for introducing Bio-materials into cells. J Nanoparticle Res 2:133-139.

2. Chen, D.R. and D.Y.H. Pui (1997). Experimental investigation of scaling laws for electrospraying: dielectric constant effect. Aerosol Sci Technol 27:367-380.

3. Chen, D.R., D.Y.H. Pui and S.L. Kaufman (1995). Electrospraying of conducting liquids for monodisperse aerosol generation in the 4 nm to 1.8 µm diameter range. J Aerosol Sci 26: 963-977.

4. Pui, D.Y.H. and D.R. Chen, (2000). Direct reading instruments for the determination of aerosols and particles. In Encyclopedia of Analytical Chemistry (R.A. Meyers, ed.), pp. 4649-4669, John Wiley & Sons Ltd, Chichester, (2000).

5. Kinney, P., D.Y.H. Pui, G.W. Mulholland and N.P. Bryner (1991). Use of electrostatic classification method to size 0.1 µm SRM particles—a feasibility study. J Research NIST 96:147-176.

 
Patents

US Patent#6,746,869 (June 8, 2004)
Pui, David Y.H., and Da-Ren Chen
"Electrospraying Apparatus and Method for Coating Particles"

US Patent# 6,399,362 B1 (June 4, 2002)
Pui, David Y.H., and Da-Ren Chen
"Electrospraying Apparatus and Method for Introducing Material into Cells"

US Patent# 6,093,557 (July 25, 2000)
Pui, David Y.H., and Da-Ren Chen
"Electrospraying Apparatus and Method for Introducing Material into Cells"

US Patent 6,764,720 (July 20, 2004)
Pui, David Y.H., and Da-Ren Chen
"High Mass Throughput Particle Generation Using Multiple Nozzle Spraying"

#US 2003/0143315A1 (Published and Pending; July 31, 2003)
Pui, David Y.H., and Da-Ren Chen
"Coating Medical Devices"

#2006/0177573A1 (Published and Pending; August 10, 2006
Pui, David Y.H., and Da-Ren Chen
"Coating Medical Devices"