Cleaning methods for pipette tips

[Jelmer Cnossen]

Hello DIYbio-ers!

I'm still a newbie at the practical lab side of biology. I'm wondering if people know [good] methods of cleaning pipette tips for re-use. 

Obviously not for the well funded labs that just buy new tips everytime, but this would reduce costs for DIYbio labs. 

I did some google searches, but so far haven't found anything. 

The reason I'm asking this is because I want to work towards building a cheap DIYbio lab robot, 

and having a cleaning system would lower cost and simplify the robot (No need to switch tips)

Would any of these things make sense: 

- Very small scale localised autoclaving? Normal tips would melt, but maybe metal tips could work here, or something else that is temperature-resistant. 

- Chemical cleaning of tips, but I guess that if you need chemicals you might as well use 

- Remove the biological compounds using other methods, maybe sound waves (Sonification)

Please contribute any crazy ideas you might have! :)

kind regards,

Jelmer Cnossen

[Jelmer Cnossen]

Oops, the second item should be 

- Chemical cleaning of tips, but I guess that if you need chemicals you might as well use new tips

- Jelmer

[Jordan Miller]

sonicating in Alconox soapy water will remove almost everything biologic that might contaminate your next sample. Then rinse. This is our preferred way to reuse most of the plastics in the lab.

also, pipette tips DO survive autoclaving, so after rinsing off the alconox with distilled water you can autoclave them in their box.

Many pipette companies will send you free samples of their tips in an autoclavable box, just ask them! If you are going to reuse tips then that one sample box should last you a good long time.

jordan

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[Andrew Barney]

I've never tried it myself, but wouldn't hydrogen peroxide work? Cells produce it as a byproduct, but in large quantities doesn't it kill cells rather effectively?

[Stephen Van Sickle]

Pipette tips are a lot cheaper bought non-sterile and loose in a bag.  We would load them in old tip boxes and autoclave them ourselves.  Saved a lot of money, but still avoided problems with cleaning used tips.

http://www.amazon.com/Pipette-Tips-1000%C2%B5L-Rnase-Dnase/dp/B003L8NOOM

-s

[Matías Gutiérrez]

The best way to get rid of any organic contamination is using sulfochromic acid. Though this will also get rid of the silicon coating that make the tips repelent to aquous solutions. They still work afterwards, but the pipetting needs to be slower - thus any optimization on how the system does the pipetting should be done with pre washed tips and not new ones. You can get rid of everything else by just running 20 volumes of water through them, that good enough dilution of any soluble contaminant for the next determination to be analytically not contaminated. 

We used to do this in a lab back in 2004, the lab didn't have much funding and it was the only way we could do research sadly.Saving money for reagents and getting the most of fungibles. It was fine and reproducible. 

Matias

[Aaron Hicks]

2011/4/13 Matías Gutiérrez <matiasgu...@gmail.com>

The best way to get rid of any organic contamination is using sulfochromic acid.

Chromic acid + sulfuric acid. Then you have hexavalent chromium (as per the movie "Erin Brokovich")- toxic, carcinogenic, and a disposal nightmare. Drinking water MCL of 0.1 ppm, with a proposal in California to drop it to 0.1 ppb.

Great stuff for getting glassware squeaky clean, but probably not the sort of thing for home use.

[Jelmer Cnossen]

Thanks for all the tips (No pun intended :P ). 

I guess I'll just start with soapy water ;)

Now on to build robots...

- Jelmer

On Fri, Apr 15, 2011 at 6:40 AM, HerbalDoc <herb...@gmail.com> wrote:

Sodium ascorbate or good old fashion vitamin c will help the body
convert hex chromium its harmless version. As an aside ;-) Sodium
ascorbate drips are what we use in the hospital for hex chromium
poisoning

On Apr 14, 9:28 pm, Aaron Hicks <aaron.hi...@gmail.com> wrote:
> 2011/4/13 Matías Gutiérrez <matiasgutierr...@gmail.com>

>
> > The best way to get rid of any organic contamination is using *sulfochromic
> > acid*.

>
> Chromic acid + sulfuric acid. Then you have hexavalent chromium (as per the
> movie "Erin Brokovich")- toxic, carcinogenic, and a disposal nightmare.
> Drinking water MCL of 0.1 ppm, with a proposal in California to drop it to
> 0.1 ppb.
>
> Great stuff for getting glassware squeaky clean, but probably not the sort
> of thing for home use.

[Mackenzie Cowell]

Hi Jelmer,

Sounds really interesting.  

1. Eva Harris describes how to build a pipet tip washing system in her book "A Low-Cost Approach to PCR".  Check page 248 for the design & pictures: http://www.scribd.com/doc/48158575/A-Low-Cost-Approach-to-PCR-Harris

2. If the forces on the tool head of your pipet-bot are much lower than those experienced by the tool head of a normal CNC / 3D printer machine, you could probably build the robot out of less expensive parts and motors.  Ilan Moyer's FoamCore CNC comes to mind: 

http://www.instructables.com/id/Build-a-Foamcore-CNC/

http://web.mit.edu/imoyer/www/portfolio/foamcore/index.html

I hope you go the extra mile and share your progress with the group from time to time.

Cheers

Mac

--
+1.231.313.9062 / m...@diybio.org / @100ideas

[Patrik]

Here's some other DIY liquid handling robots:

BioBrick-A-Bot: http://2009.igem.org/Team:Washington-Software

Liquid handling robot: http://openwetware.org/wiki/Mike_Barnkob:Projects/Liquid_handling_robot

[Jelmer Cnossen]

I hope you go the extra mile and share your progress with the group from time to time.

Definitely, I'm a big fan of open source robotics 

Patrik: Thx for the links, it's good to know what's out there. I think I'm going to skip the Lego's though, I want something consisting of cheap electronics that can be bought in bulk, and lego is very likely more expensive.

[Patrik]

> Patrik: Thx for the links, it's good to know what's out there. I think I'm
> going to skip the Lego's though, I want something consisting of cheap
> electronics that can be bought in bulk, and lego is very likely more
> expensive.

Sure - I definitely didn't want to imply you should go the Lego route.
In fact, I think you could probably adapt one of the many open 3D
printer or CNC designs to develop a liquid handling robot - those
typically have far more resolution already than you'd need to address
a 384 well plate. Plus you don't really need a full Z-stage, just up/
down. Here's a bunch of open 3D designs you could borrow from:

http://www.makerbot.com/
http://reprap.org/
http://www.aquickcnc.com/
http://www.mydiycnc.com/
http://opensourcecnc.blogspot.com/
http://www.cnczone.com/

Or you could go for a more cobbled-together approach ;-). I remember
at one point, the Church lab at Harvard had this "robot" which was
essentially a set of flasks and plates set around the edge of a
horizontal bicycle wheel. A little motor would rotate the wheel
clockwise or counterclockwise, and an automated pipetter would dip
down and transfer liquids.

[Prashant Bharadwaj]

Hey, Did you try out anything? How did it go?  I was curious!

[Sai Kiran Javvaji]

Good afternoon Mr Jordan

If you have a protocol that you follow for the below, can you please share the same with me?

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