Hi,
Temperature and %rh probes.
It is useful to measure temperature and relative humidity in your incubator
and there is a superb company that produces excellent probes for doing this
on the cheap:
http://www.picotech.com/temperature-humidity.html
Price depends on accuracy: +/-0.3oC or +/-0.01oC, the former being fine for
most. I use the £135 three probe Th-03 system that’s accurate to +/-0.3oC,
although there’s the more expensive [£400 single] platinum resistance probe
that’s accurate to +/- 0.01oC or more. Temp measurement is a complex thing
with probes, e.g. conduction heat loss down the probe etc… but they do give
a useful indication of the temp where the cells are rather what an external
control box says. Pico also make a very cheap software oscilloscope and %rh
probes. My PhD is in fuel and combustion, so thermocouples and stuff are
second nature to me, but these Pico data loggers are great value, and simple
to use [although the TH-03 probes are a bit large for some situations].
Evaporation
Yes you can use mineral oil for long term time-lapse, but some worry about
gas exchange and toxic effects [well I do]. A preferred option would be
special ‘gas not water’ permeable membrane lids/seals for your small Petri
dish to virtually eliminate evaporation: e.g. Zeiss Foil Cover and CultFoil
Foil Covers “that extend the incubation time considerably by reducing
evaporation. A special foil (CultFoil), gripped between two thin steel
components, replaces the usual cover of the culture vessel. The foil
effectively reduces the amount of water vapor that is able to escape. Gas
exchange is not affected.” But they aren’t as cheap as mineral oil.
Generally we just humidified the air in the incubators to reduce evaporation
rates. For short term [2-4 hours] I used to just put a beaker filled with
water and overhanging tissues into the incubator [if it’s a large one],
although you need to change it daily to prevent it getting smelly. However
for long term time-lapse we always used the Zeiss [PeCon] humidifiers that
fitted in-line to air circulation system [cost about £500 each], and these
worked very well. All our systems were Zeiss/Leica and so PeCon friendly.
For CO2 we trusted our fantastically expensive variable% Zeiss CO2
controllers [or the 5% CO2 label on the BOC CO2 cylinder].
Humidifier:
http://www.pe-con.de/pecon/index.htm
search for relative humidity
Regards
Keith
---------------------------------------------------------------------------
Dr Keith J. Morris,
Molecular Cytogenetics and Microscopy Core,
Laboratory 00/069 and 00/070,
The Wellcome Trust Centre for Human Genetics,
Roosevelt Drive,
Oxford OX3 7BN,
United Kingdom.
Telephone: +44 (0)1865 287568
Email: [log in to unmask]
Web-pages: http://www.well.ox.ac.uk/cytogenetics/
________________________________________
From: Confocal Microscopy List [mailto:[log in to unmask]] On
Behalf Of Zoltan Cseresnyes
Sent: 12 February 2009 23:22
To: [log in to unmask]
Subject: Re: CO2, humidity, temp sensors
Paul,
We have a similar system and have been using it successfully after spending
some time to tune the 5% CO2 flow rate until the pH stayed constant (judged
simply by the colour of the medium), and after placing several beakers of
water within the 37C area to humidify the warm air and thus keep the
evaporation rate low. This way experiments can be done overnight w/o cells
dying (appr. 17 hours).
Hope this helps a bit.
Zoltan
On Thu, Feb 12, 2009 at 7:23 PM, Paul Herzmark <[log in to unmask]> wrote:
I have a cell dying problem in my microscope when I take pictures of them
overnight or longer. I suspect the humidity is failing and I want to monitor
that, CO2 and temperature.(It is not photodamage. Cells die in areas away
from the objective.)
Can anyone suggest a supplier of recording sensors that I can get next to
the well slides on my stage?
Thank you!
Paul Herzmark
Specialist
[log in to unmask]
Department of Molecular and Cell Biology
479 Life Science Addition
University of California, Berkeley
Berkeley, CA 94720-3200
(510) 643-9603
(510) 643-9500 fax
--
Zoltan Cseresnyes
Facility manager, Imaging Suite
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