Team:Aachen/OD/F device
From 2014.igem.org
(→From Transmittance to True Optical Density) |
(→OD device) |
||
Line 90: | Line 90: | ||
For our OD device we needed to correlate the transmittance measured by our sensor to an optical density anyway. | For our OD device we needed to correlate the transmittance measured by our sensor to an optical density anyway. | ||
- | Our team members from the deterministic sciences emphasized on the correction method, which was conducted according to [1]: | + | Our team members from the deterministic sciences emphasized on the correction method, which was conducted according to Lawrence and Maier [1]: |
* The relative density ($RD$) of each sample in a dilution series is calculated using $\frac{min(dilution)}{dilution}$. | * The relative density ($RD$) of each sample in a dilution series is calculated using $\frac{min(dilution)}{dilution}$. | ||
Line 99: | Line 99: | ||
The derived function allows the conversion from transmission to optical density on our device and therefore calibrates our device. | The derived function allows the conversion from transmission to optical density on our device and therefore calibrates our device. | ||
- | Lawrence and Maier could | + | Lawrence and Maier could show that correcting transmittance this way, the corrected optical density shows a linear relationship between true optical density and dry weight in cell suspensions. |
- | In our experiments we | + | In our experiments, we find that different cell types have a different correction function. |
- | While this at first sight looks disappointing, it | + | While this at first sight looks disappointing, it should be expected: |
- | Transmittance is the fraction of light coming through some medium relative to | + | Transmittance is the fraction of light coming through some medium relative to the cell-free and clear medium. |
- | + | However, the transmittance is not only depedent on the amount of cells in the way of the light beam but also on the cells' shape, their size and possibly also their cell membranes. | |
[1] Correction for the Inherent Error in Optical Density Readings, Lawrence, J.V. and Maier, S., Applied and Environmental Microbiology, 1977, p. 482-484 | [1] Correction for the Inherent Error in Optical Density Readings, Lawrence, J.V. and Maier, S., Applied and Environmental Microbiology, 1977, p. 482-484 |
Revision as of 06:44, 13 October 2014
|
|
|
|
|
|
|