aerodynamic flow fucussing

Specification

Principle of technology

In aerodynamic flow focusing, a laminar jet of precursor liquid passes a nozzle, of appropriate diameter, and is guided to an exit orifice which is centrally in line with the axis of the nozzle. A pressure drop between the nozzle and the exit orifice leads to an aerodynamical effect, so that the jet has a smaller diameter when it passes the orifice as compared to the nozzle. The size of the droplets is determined by the product flow rate, the pressure drop and the nozzle diameter, and can be controlled down to 10 micrometers. The droplets are further processed into particles by cross-linking or polymerization (hardening process) of the precursor liquid. The hardening process must be very fast in order to achieve optimal particle quality.

Aerodynamic flow focusing technology is optimal for the production of microparticles in the size range of 10 to 200 micrometers at relatively low volumetric production rates.

Materials that can be processed

• Alginate: hardened by crosslinking with bivalent metal ions; alginate particles can be further processed to result in coated particles as alginate-polylysine-alginate, alginate-polyethylenimine or multiply coated systems
• Agarose: hardened by thermal gelation
• Waxes and paraffin: hardened by thermal solidification

Application examples

• Microencapsulation of single cells for screening applications
• Invisibly small encapsulated food supplments
• Injectable pharmaceutical formulation

Micro beads from fluorescently labeled sodium alginate (mean diameter 35 micrometers) produced by aerodynamic flow focusing technology.