Team:York/Measurement
The DIHM Analysis Technique
We have developed a digital inline holographic microscope and related software that can be used in conjunction to analyse the shapes, sizes and growth rate of microorganisms. We also speculate that, with some improvement, the same hardware and software could be used to observe and quantify the motility of cells.
On our Results page, we have provided evidence to show the validity of our technique with respect to shape, size and cell-count measurements. As can be seen therein, we have been able to measure the features and density of cells in mono-cultures and samples containing more than one species. We therefore propose that the use of digital inline holographic microscopy is suited to characterising the effects of Parts which influence (or are expected to influence) the growth rate or structure of microorganisms.
As an example of growth rate related characterisation, consider the characterisation of the registered Part BBa_K1893016 (iGEM Imperial College 2016), which inhibits the growth of E. coli. This characterisation could have been performed by DIHM analysis. A parallel can be drawn to the optical density measurements that Imperial College used during their characterisation, since the growth rate would be calculated through repeated cell-counting via our technique. Moreover, along with being able to calculate the growth rate, the DIHM analysis allows for individual cells to be observed. It is plausible that other characteristic effects of BBa_K1893016 could be found by observing the behaviour of the individual cells.
For another example, consider a Part that alters pili production, such as BBa_K1850006 (iGEM Harvard BioDesign 2016). This has been shown by Harvard BioDesign to affect agglutination of yeast. It would be straightforward to observe this under our DIHM since the clumps of cells that are formed during agglutination are likely to be orders of magnitude larger than individual cells - a difference in size that we have shown it is certainly possible to observe with our hardware and software. It is, therefore, reasonable to conclude that our technique is also suited to characterising this type of behaviour.
Unfortunately, we have not been able to perform any such characterisation ourselves, though we do have the proof of concept.
