# Where do you buy your pathogens, parasites, bio-simulants, etc?

1. Nov 25, 2008

### flying fish

For a research project, I am trying to get either simulants, or real water parasites that have been inactivated (in particular Cryptosporidium and Giardia).

I've found some options for actual crypto, like the Sterling parasitology lab at the University of Arizona. But they want 200 bucks per ml of the concentration of parasites that I would be working with...which could potentially work for certain parts of my research that only require small amounts (like the optical tweezing I mentioned in another thread), but for "bulk micro-separation" (another parallel project) I would need a more affordable substitute.

And I still haven't found a source for Giardia.

One thing that comes to mind as a possible simulant is yeast....It is a fungi, but doesn't it also form spores which are similar in size to crypto?

2. Nov 26, 2008

### chemisttree

If you only want a simulant that is roughly the same size as the oocysts (4-6 micron for crypto and 6-10 micron for giardia) you might look at synthetic latex of that size. They can be made fairly easily in your laboratory. You would only need to show that the latex particles behave the same as your (valuable) biological samples with small scale experiments and then scale it up using the cheaper latex 'simulant'.

I wonder if red blood cells (6-8 micron) might work?

3. Nov 26, 2008

### flying fish

I do like your idea of using the real bio's to help verify a simulant that can be used for continued (and less expensive) studies.

I think the latex spheres may work for the "micro-centrifuge" that I'm working on, which is actually the thing that requires the most particles, because it is designed for sorting lots of particles in relatively high volumes of fluid.

Then for the other things...like optical sorting, and ultimately trying to make an automated detector for these things, we probably would need the real bios or something very close.

4. Dec 4, 2008

### Charion

Depending on the properties according you want to sort them (I did not read the mentioned other thread yet) it may be necessary to actually use the right organisms (possibly even life ones). Problem is that if you do not have the ability to cultivate these organisms, they tend to get rather expensive in any case.
Most strains are available for instance from the ATCC, however usually it will cost you 150-500$per sample. 5. Dec 4, 2008 ### flying fish Thanks! I have not found the ATCC previously in my searches. They will mostly be sorted according to size, although other things like refractive index and buoyancy might also come into play. I'm investigating two systems for sorting - one that uses optical trapping to steer particles according to their size and refractive index (and thus trapping efficiency), and one that utilizes a bunch of crazy fluid mechanics principles that I'm still trying to understand. I did find a supplier that sells Giardia in a concentration of 10^6/ml, but as you say, they are not cheap - around$500. "In theory" that is enough to work with...but of course right now I'm working with microfluidic chips that are not actually bonded but rather mechanically clamped, so there would be a good deal of leakage and thus loss of fluid and the organisms suspended in it. It might be possible to re-capture and re-use them, but everything would have to be super clean to prevent contamination, and I'm sure there could be other problems with this plan.

On one hand - If we use a very low concentration of parasites, it will be hard to find them under our imaging system, and thus hard to prove that we are sorting them. On the other hand...We do need to learn how to pre-concentrate and sort from an extremely low concentration - because even "extremely low" concentrations of Giardia in drinking water are relatively high from the perspective of someone that is going to drink the water!

All I know is that it would suck to dump \$500 worth of parasites into the chip and not have any success.

6. Dec 5, 2008

### Charion

For proof of principle experiments it may be sufficient to use a mixture easily cultivable non-pathogenous protozoa (or yeast, as you mentioned) for your experiments. That is, if you have some facilities near you that you could use (at least an autoclave and maybe an incubator).
As for the moment I assume it should be sufficient to demonstrate that the cells can be sorted at all.

7. Feb 10, 2010

### bunchgrass

A little late but - we sell Cryptosporidium oocysts. Flying fish, if you or anyone else is interested in more information, send me an e-mail: pritchard@turbonet.com
Hope your experiment worked out.

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