HI

WHAT DISINFECTANTS CAN BE USED TO CLEAN THE WORKING SURFACE TO REMOVE DNA or PCR PRODUCTS COMPLETELY AND HOW TO REMOVE AEROSOL CONTAMINATION WITH THESE (OTHER THAN UV) ?. HOW EFFECTIVE METHANOL WILL BE?

THANKS

Hi Priya,

i work with RNA and use the following procedure to clean my bench with, although it probably is a bit excessive

First rub down with a small amount fo detergent, then I wash with absolute ethanol, and then wash with 20mM sodium hydrixide which is sufficient to break up nucleic acids.

Hope this helps

Sarah

Hi
i've the same guidelines, except using an antistatic agent included in the detergent and 70%ethanol.

RNAse away and DNAse away from Ambion also work well on the bench and pipetts.

Hey Priya hows it going?

To answer your question theres all sorts of methods and re-agents to use and be rid of contamination.

The types of re-agents Im talking about would be the following; Chlorox, Virkon which are your bleaching agents; on the other hand, there 70% ethanol and vira-clean your frequently used bench-top cleaners in and out the hood of course, including little spills around tubes.

Any of the cleaners listed above may be used to clean but depending for wat purpose and samples. General for all surfaces 70% ethanol would best be used, you can use vira-clean but in the hood I would advised not to because vira-clean used in hood becomes acidic.

Chlorox at 1-10% can be used on benchtops but from experience, very potently smelly. Virkon only use this stuff as a waste bottle inside the hood or if you use things such as medi-vacs which is a waste container system then use.

Other than that, the above mentions the necessary type of cleaning agents in your lab (P2) that is.

hi
thank you all for ur suggestions.
actually i m doing nested PCR and m already suffering from contamination in negative control( exact size bands).

what about sodium hypochlorite. all these chemicals how exactly they work? i think the dna just gets fragmented but not removed completely.
moreover absolute ethanol is sometimes recommended for storing clinical samples for dna extraction later. so does it harms dna in any way.can u clarify it please?

thanks

People are confusing killing cells with removing DNA. 70% ethanol will kill cells, but will have essentially no effect on DNA. You precipitate your DNA with it, and wash the DNA with it, after all.

Bleach, NaOH, or HCl, with some detergent will work. UV exposure will work.
Commercial solutions like DNA-away or DNA-Zap are effective.

The simplest solution we've found for bench-top contamination is to buy a big roll of the plastic-backed paper lab bench "diaper" and change it frequently. I thought aerosol contamination is best solved by using barrier pipette tips, but maybe that's not what you meant?

To reduce aerosol contamination, I do not work in a PCR hood...however I have permanently shunted all the airvents in the lab away from my PCR bench, then I disinfect the bench, then I run the bunsen burner to keep any aersols moving up in the air and not settling down onto my stuff

we work with staph and skin cells so I am always paranoid about contamination from myself...my tips are all nuclease-free (although not always filtered; I usually use the rainin ones without the filters) but I take my pipettors apart and clean the barrels often to keep contaminated aerosols from hanging out in there, and use dedicated pipettors for before-and-after steps

if your neg control is showing up bands, what about all your reagents? I would suspect water or buffers first

do you have an ID badge that hangs into what you're doing all the time?

do you wear the same lab coat for lots of PCR and not wash it often?