Monday, November 29, 2010
H2O2 is stable if stored correctly - it's been used as a storable rocket fuel oxidiser for instance. However, it can be broken down by an inorganic catalyst.... Perhaps we could inject, say, a palladium slurry instead of catalase?
But it's all just more and more plumbing!
Catalase is a much more efficient catalyst for breaking down H2O2 (hence it's name) so it would be fun to see how Catalase, Bugbuster and TwistDX co-exist! Or Palladium, come to that.
does hydrogen peroxide have a relatively short hald life? could we take advantage of that? or will the cold prevent in breaking down by itself?
If I can tear you away from Fluxx for a moment, what do you think of the below?:
Basically H2O2 is the gold-standard for astrobiological decontamination, but can we do this in flight?
Are we getting closer and closer to the minirobot idea?
(I.e lots of things to pipet so a pipetting robot not valves?)
Many thanks, Lynn - if we tried to disinfect a system in the field or during flight (my long-term ideal) we would need to flush out or neutralise the H2O2 before adding reagents (eg TwistDX etc). The question then is whether the reagents can tolerate the presence of Catalase etc. Unless we need to flush out the Catalase etc too...
For trying to sample at altitude, something like Catalase might be problematic since the relatively high torr O2 released might nuke anything in the sample (since it would have evolved in a far less O2 -rich environment)
Perhaps this protocol is best used for in-the-lab sterilisation? I have often thought that actually we have access to a lot of plasticware that has been gamma-irradiated (the gold standard for being sterile AND is DNA-free, which is a separate criterion) and we could then try to sterilise plumbing etc (eg Tygon) with H2O2?
This is somewhat what I had in mind for this summer's HAB device but in practice the syringes etc needed too much fiddling to mount them sterile. I tried a ethanol flush during the rocket launch preps but that's a moot point now :-O ;)
Fw from Lynn
I did conduct a literature search on Hydrogen Peroxide for spacecraft cleaning.
As noted for astrobiology/planetary protection for the mars missions of the 70s Solutions of 3, 10, and 15% hydrogen peroxide were found to have pronounced bactericidal effects, as a function of time of exposure, on sporeformers and nonsporeformers isolated from spacecraft. Find the attachment, applmicro00028-0236
It appears the UMS should be cleaned with the least toxic concentration 3% as exposure time can be long 4 hours.
The disinfection Nov 2008 guide has a selection of agents for disinfection listed if H2O2 cannot be used.
I hope all is well
Tuesday, October 5, 2010
This is a quick announcement to say that our bruised and battered flight computer has been sent back to its manufacturer for a computer autopsy. Fingers crossed!!
Tuesday, September 7, 2010
Friday, July 16, 2010
Somewhat crestfallen - could not get my experiment to work properly due to a last minute electrical problem.(On wednesday it almost caught on fire!!)
But I will fly it on balloon anyway - I'll be able to talk to its computer using a special radio link whilst it is flying; that is still pretty cool! :-)
I am hoping I can get it to work during the week and do some experiments on the ground too - that will be quite interesting in such a big desert (is there anything alive there?...)
So I will try to enjoy everything even if the actual flight isn't perfect.
Tuesday, June 29, 2010
The last few months have flown by and we haven't had a moment to update on our progress on the blog. Ol has been flat out, pulling all nighters to finish the device, which you can see in the picture. There have been nightmares about reagent compatibility and he has manged, with almost unbelievable cunning, to fit four syringes in to the device to pipette in the required quantities of liquids in the right order. Paul and Ol have been doing all kinds of things, remotely from Canada in Paul's case, to ensure everything will work.
We have also run a competition with NESTA and NASA for 2 students to come with us to Nevada to fly the device - welcome on board to Joe and Rainbow. We had 120 applicants and it was really hard to chose even the last 6 finalists, nevermind the 2 winners! Rachel down at NESTA has been in an organising frenzy, sorting out logistics - accommodation, flights, food (you would never normally have to put so much effort in to camping, we're just going to not have a lot of water so many things will be tinned) and much more.
With only a few days remaining before Ol heads to NASA AMES we are thinking very hard about how to get our reagents to California with out breaking any laws, but also crucially keeping them all cool. Then Rachel, Paul, Joe and Rainbow will head out, getting a brief trip to NASA too, and then I'll go out last (hampered by a conference the week before!). 12 days in the Nevada desert - to fly the device as many times as is possible - on balloons and rockets! The people we're teaming up with are the Rocket Mavericks. We're going to the Black Rock desert - home of the burning man festival. There's no phone coverage and its very remote (austere as Ol says), so we're taking GPS and satalite phones and all kinds of wizardry - hopefully there'll be some good star gazing too.
We've also been in discussion with Kira O'Reilly and Anna Dumitriu for possible art interventions and collection of materials whilst on location in the desert. Currently we're thinking of making extensive diaries and trying to communicate with bacteria.
Saturday, March 6, 2010
The first ever HAB dream? Unless one of you can better :-)
I have now ordered a batch of non-sterile syringes and tubing, and established a wiring colour scheme for the main circuits (it was getting confusing with 5V, 12V and 3.6V high Ampage components)
I spent some time agonising about incubation temperatures for the TwistDX reagents and in fact if we can't get it to work, we could always test at ambient room temp to start with. Having said that, I have bought:
A professional combined probe and infrared foodgrade thermometer - will try both approaches. I wanted a probe or as small as possible otherwise the thermal mass of the probe ends up setting up the sample temperature and not the other way round!
As it is, the chamber looks like being at least 12mm long to accomodate the probe during testing. The probe hole will be sealed up later.
An IR spot might work - we need an optical window in the incubation chamber anyway for the PicoGreen measurement - but even the smallest spots on various instruments were over a cm, which seems unfeasibly big?
As a curveball, I will also try thermocolour plastic (like those forehead FeverStrips)
For the actual incubation, I will try resistive wire, maybe wound around the incubation. I have also found a small hotplate to sit the chamber on, and also a miniature water heater, and to go with that a miniature immersive water pump! (with water tubing wound around the chamber)
So it could be barheateresque, hotplatesque or central heatingesque!
Will keep you posted!
Oliver de Peyer PhD
Division of Molecular Structure
National Institute for Medical Research
Tel 0208 816 2688
Fax 0208 816 2580
Mobile phone +44 7908 783367