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S. Almo

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Mar 23, 2021, 1:22:28 AM3/23/21
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Hello

I want to be able to reuse my tips, tubes and needles. as i am mainly using those to train for biological techniques at home using my bento lab. i do not have the money to buy more tips and tubes. is there a way i can autoclave at home or just deep wash them.

Any suggestions?

M Marcus

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Mar 23, 2021, 2:42:09 AM3/23/21
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Do you have pressure cooker at home. It's internal temperature reaches 121 deg celsius when it reaches the first whistle. So 20 minutes of those items  inside a pressure cooker is autoclaving. It costs around 150 dollars. Or you can loan  a used one from one of your indian friends for free . 

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M Marcus
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Frank

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Mar 23, 2021, 3:05:58 AM3/23/21
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is the radiation  in a microwave oven not sufficient to sterilize?

S James Parsons Jr

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Mar 23, 2021, 6:27:44 AM3/23/21
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Bleach is cheap, just make sure the tips don’t melt 

Sent from my iPhone

On Mar 23, 2021, at 3:05 AM, Frank <fgarc...@gmail.com> wrote:



Cathal Garvey

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Mar 23, 2021, 7:53:52 AM3/23/21
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In this vein, using a dilute peroxide-based bleaching agent such as sodium percarbonate might be a nice pre-wash before autoclaving. Peroxide bleaching (followed by rinsing with cheap car-grade deionised water) will go a long way toward decontaminating and removing residues, and the peroxide will decompose entirely within the autoclave whereas chlorine bleaches might leave residues.

The deionising rinse may be necessary though because sodium percarbonate would perhaps otherwise leave a minor salt residue that could mess with some molecular work. 

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23 Mar 2021, 10:27 by sjamesp...@gmail.com:

Rikke Rasmussen

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Mar 23, 2021, 4:29:21 PM3/23/21
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In my experience, most pipette tips do not autoclave well - since the tips are generally compression-fit onto the pipette, even slight deformations on the plastic lead to inaccuracies in pipetting performance.

My suggestion would be to buy a cheap sonicator off eBay and do as follows:
1) pre-soak your tips for 20-30 mins in 10% bleach (which will kill any living organisms, and thoroughly oxidize both nucleic acids and proteins)
2) rinse in water a couple of times (it's important to get rid of all the bleach, which will otherwise interfere with downstream applications)
3) sonicate your tips for 10-20 mins in clean water
4) do a final rinse in 70% IPA / EtOH, rack while wet and dry under HEPA-filtered air flow (a standard laminar hood will do the trick)

If you have access to a 3D printer, this tool will make your life much easier: https://www.labonthecheap.com/3d-print-a-pipette-tip-sorter/

To view this discussion on the web visit https://groups.google.com/d/msgid/diybio/MWTvjkK--3-2%40cathalgarvey.me.

Daniel C.

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Mar 23, 2021, 4:41:24 PM3/23/21
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A pressure cooker may not be ideal for this situation because of the tight tolerances of pipette tips, but they do work very well as a home autoclave.

However, it's important to note that not all autoclaves are calibrated to the same pressure. That means they will reach different internal temperatures. I don't have the formulas in front of me but it should be pretty easy to calculate the max internal temperature based on the pressure your equipment can reach.

Also, someone correct me if I'm wrong, but I believe that you don't need to worry about altitude with a pressure cooker. Normally water would boil at a lower temperature as you go up in altitude. But pressure cookers work by setting a calibrated weight on top of the steam vent. That should eliminate the impact of atmospheric pressure, so us mountain dwellers don't need to worry that we're not getting adequate sterilization.

Again, please correct me if I'm wrong on that, I've never taken a physics class in my life.

Cheers,
Dan


To view this discussion on the web visit https://groups.google.com/d/msgid/diybio/CAKeDxcLnTxo2UgSO1WNvRfPF3xAEwUj8LmQiJMKtbEecc8Bx7w%40mail.gmail.com.

Tom De Medts

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Mar 23, 2021, 10:07:37 PM3/23/21
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Hi Almo,

PART 1. LOGIC OF RE-USE 
Your cleaning protocol depends essentially on 2 things:
1. what did you already use the tips for?
2. what do you intend to use it for, next time?

Because you mentioned Bento Lab (link), I am assuming you were referring to the integrated PCR machine, centrifuge, gel electrophoresis apparatus.
So I am assuming your pipet tips were used for nucleic acid application.

So if you used it for PCR setup first, and want to use it for protein work next, and your protein samples will be OK despite some residual nucleic acid contamination,
then your whole time, money and other resources spent in decontamination might be worth it...

But if you used the tips already for PCR and wish to use it again for a different PCR reaction, then you should be ready for unexpected results, 
even if you think your decontamination was performed perfectly. If you are willing to risk such an outcome, or if it does not bother you, then no worries...

PART 2. AUTOCLAVING
Autoclaving at 121C for 20mins is the best approach to get rid of microbial contamination,but not at all the preferred method for getting rid of certain chemicals / biopolymers, e.g. DNA.
Yes, autoclaving is independent of external altitude, pressure, temp etc. since the pressure chamber is self-contained, and yes, the weight on the pressure cooker lid determines when pressure is released.
Depending on the wattage of the stove, you will need to play around with the setting so that the duration of your 121C exposure is neither too short, nor too long of a duration, but as close to 20 mins as possible.
One way to know if your autoclaving was too weak is to use relatively inexpensive autoclave tape ~ $10 for a roll at amazon.com
It will however not tell you if your autoclaving is for too long a duration. For that use your cheap but trusted timer...
I do not autoclave extremely temperature sensitive reagents or chemicals, but when my media contains sugar(s), I try to make sure I do not start to smell caramelization.


PART 4. ADDITIONAL NOTES - WATER & DETERGENT
Water - You will need distilled water for any rinses - I do not buy this, but purchased a water distiller from eBay (Made in China) and a pH meter cum conductivity meter to make sure it is close to pH 7.0 and as close to 0 µs/cm.
Detergent - And generally, for most mol. biol. applications, you will also need some special lab-application detergent, usually phosphate free ones, like the ones sold by Alconox (powder or liquid work well). I would not use general dish or dish-washer or laundry detergent or bath soap etc.

PART 5 - RANDOM IDEA
Have you considered contacting a larger DIYlab in your area that may be ordering a larger bulk, and who may be willing to re-sell smaller aliquots to members / customers such as yourself?

Good luck!
Tom

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jlund256

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Mar 24, 2021, 10:11:41 AM3/24/21
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S. Almo,

You received some good replies, but I think the first question has to be, what techniques are you performing with the tips and tubes?  If your experiments are microbiological, the labware would need washing or rinsing, and then sterilization is key.  If you are doing DNA extraction, and then PCR or enzymatic techniques with DNA, then washing and rinsing will likely be fine--things don't really *need* to be sterile, more important is removing bulk contaminants and DNA, and a bleach treatment will destroy DNA.  If you are working with RNA, then more strenuous steps are needed, etc.  So think about what you are doing, and what type(s) of dirt or contaminant you need to remove.  In some cases, dishwasher or equivalant washing is enough. 

It was common to use glass pipets before plastic became cheap, and they would be cleaned with a bleach treatment followed by several rinses in water / deionized water.  You may find instructions in general lab practice books or try googling around.  Plastic will not hold up for as many cycles as glass.

Cheers,

Jim Lund

S. Almo

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Mar 27, 2021, 7:59:27 PM3/27/21
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I will be using blood mainly to extract plasma and isolate DNA and specific proteins.

Hans Wilms

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Mar 28, 2021, 7:22:24 PM3/28/21
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If you wanna autoclave at home, just buy a cheap pressure cooker off amazon and cook your stuff in there for 20min at 15psi/121C. Its the same thing. That is what I always used to do and it works wonderfully on tips, glassware, etc. Just make sure whatever you're using is autoclavable. Don't know about reusing tips though.

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