Overview

Alginate beads are commonly used for immobilization of macromolecules and cells, however, they are also applied for pharmaceutical purposes such as drug delivery. The polymer

Production

Bacteria are resuspended and diluted in NaCl-solution (0.9 % in H₂O) so as to achieve the desired cell density. Here, we aimed at a comparably high concentration of 10⁷ bacteria per bead. The resuspension was added to alginate (2.5%) to reach a alginate concentration of 2%. The viscous solution is filled into a syringe containing an appropriate needle device and extruded at a constant, slow velocity. Ideally, the droplets should fall form a height of approximately 30 cm into a 100 mM CaCl₂ solution. In the CaCl₂ solution gelling of the alginate droplets will occur instantaneously. To avoid excessive salt stress for the bacteria the beads should be transferred to a 10 mM CaCl₂ solution.

A more detailed protocol can be found here.

Loading the Chip

The beads are better visible in liquid when light shines from the side. So it's easier to load the the chip with help of a cell phone light.

Features