Immobilization of Cells Using Electrostatic Droplet Generation

A major concern in cell and bioactive agent immobilization has been the production of very small microbeads to minimize the mass transfer resistance problem associated with large diameter beads (i.e., >1000 �m) (1 ). Conventional technology involves production of alginate beads with diameters ranging from 500–2000 �m using compressed air to quickly pass the cell/gel solution through a nozzle (2 ). Surprisingly, only recently have attempts been made in the application of electric fields to the production of micron-size polymer beads for cell immobilization (3 –8 ). The two primary advantages of electrostatic droplet generation, over, for example, an air jet extruder, are the production of much smaller beads with conventional needles and ease of bead size control by simply varying the applied potential.