Team:ETH Zurich/lab/bead

From 2014.igem.org

(Difference between revisions)
(Production)
(Overview)
Line 5: Line 5:
{|
{|
-
[[File:ETH2014_BeadLogo.jpg|left|300px|thumb| Bead production]]
+
[[File:ETH2014_BeadLogo.jpg|left|300px|thumb| Na<sup>2+</sup> alginate is extruded through a needle device]]
Alginates are present as structural components in both the cell walls of brown algae and the capsules of soil bacteria. However, commercially available alginate is mainly extracted from algae. The polysaccharides find a broad application in various fields: in textile printing, in food industry or in research. The chemical features of alginates allow immobilization of macromolecules and cells, thus, the compound is commonly used in biotechnology, biomedicine and pharmacy<sup>[[Team:ETH_Zurich/project/references#refEmergence|[24]]]</sup>. In our project we encapsulated bacteria in alginate beads so as to ensure local separation of the different units (here strains) and directional communication between them. These prerequisites are required for controlled pattern formation.
Alginates are present as structural components in both the cell walls of brown algae and the capsules of soil bacteria. However, commercially available alginate is mainly extracted from algae. The polysaccharides find a broad application in various fields: in textile printing, in food industry or in research. The chemical features of alginates allow immobilization of macromolecules and cells, thus, the compound is commonly used in biotechnology, biomedicine and pharmacy<sup>[[Team:ETH_Zurich/project/references#refEmergence|[24]]]</sup>. In our project we encapsulated bacteria in alginate beads so as to ensure local separation of the different units (here strains) and directional communication between them. These prerequisites are required for controlled pattern formation.
|}
|}
Line 28: Line 28:
===Production===
===Production===
{|
{|
-
[[File:ETH2014_BeadsProduction.jpg|left|250px|thumb| Na<sup>2+</sup> alginate is extruded through a needle device. Gelling of alginate occurs in the CaCl<sub>2</sub> solution that is the beaker placed under the needle]]
+
[[File:ETH2014_BeadsProduction.jpg|left|250px|thumb| Alginate droplets are gelling in the CaCl<sub>2</sub> solution in the beaker placed under the needle device]]
Bacteria are resuspended and diluted in NaCl-solution (0.9 % in H<sub>2</sub>O) so as to achieve the desired cell density. Here, we aimed at a comparably high concentration of 10<sup>7</sup> bacteria per bead (3 mm diameter). 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 CaCl<sub>2</sub> solution. In the CaCl<sub>2</sub> 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 CaCl<sub>2</sub> solution.  
Bacteria are resuspended and diluted in NaCl-solution (0.9 % in H<sub>2</sub>O) so as to achieve the desired cell density. Here, we aimed at a comparably high concentration of 10<sup>7</sup> bacteria per bead (3 mm diameter). 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 CaCl<sub>2</sub> solution. In the CaCl<sub>2</sub> 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 CaCl<sub>2</sub> solution.  
<br>
<br>

Revision as of 20:58, 15 October 2014

iGEM ETH Zurich 2014