Preparing competent cells under laminar flow? - or on the bench sufficient? (Apr/13/2010 )
Hi all,
I've always made my chemically competent cells myself and I always prepare them on my bench. until the last part of addition of glycerin.
I prepare TOP10 and on the invitrogen protocol there is no sign of preparation under laminar flow. It's common sense to prepare under laminar flow to have the least contamination, but I've never had any problem so far.
my friends say my TOP10 might get contaminated with other bacteria and not work properly after a while.
I think there are very very few things you need a laminar flow hood for in working with bacteria, other than to protect yourself from pathogens. Your bench should be just fine.
Over the last twenty years, I've made countless batches of chemically competent E. coli. Never once did I use (or, to be honest, even think about using) a hood. You'll be fine...
I also never prepare mine in the hood, even the last step. Everything is done on bench. 
Curtis on Apr 13 2010, 11:36 AM said:
I've always made my chemically competent cells myself and I always prepare them on my bench. until the last part of addition of glycerin.
I prepare TOP10 and on the invitrogen protocol there is no sign of preparation under laminar flow. It's common sense to prepare under laminar flow to have the least contamination, but I've never had any problem so far.
my friends say my TOP10 might get contaminated with other bacteria and not work properly after a while.
There is no need to use a flow; the risk to contaminate the flow with bacteria is higher than to spoil your preparation;
(in some labs it is done when they have more laminar flow capacity than normal benches)
if someone is preparing bacteria in my laminar flow hood i will kick him out of the window 