Patent ID: 7728070

Claim:
A method of producing aqueous cross-linked polymerization hardened droplets carried by a hydrophobic stream in a microchannel device, comprising feeding a first aqueous stream having a volumetric flow rate Q 1 comprising a source of metal ion salt, a second aqueous stream having a volumetric flow rate Q 2 comprising a source of acidity and a third hydrophobic stream having a volumetric flow rate Q oil , wherein a biopolymer is in one of the aqueous streams and the aqueous streams merge into each other before or at the same time as they meet the hydrophobic stream, thereby forming aqueous droplets which subsequently harden by cross-linked polymerization by generation of metal ions and wherein the flow rates Q 1 , Q 2 , and Q oil are chosen such that droplet formation proceeds un-hindered and gelation only occurs after drop formation is completed thereby decoupling the process of droplet formation and gelation.