perfusion system

[Hana Uhlirova]

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Dear list,

Has anyone experiences with perfusion system for live cell imaging?
Particularly I need to rinse with two liquids of precise concentration. We
have a home-made closed system and have problems with air bubbles and mixing
of those liquids by loss of the concentration accuracy. Any tips how to
figure this out?

Thank you all.

Hana

Hana Uhlirova PhD
Laboratory of Optical Microscopy
Institute of Physical Engineering
Faculty of Mechanical Engineering
Brno University of Technology
Czech Republic  

[ugez323]

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You could try an HPLC pump. These quite often meter more than one channel at
flow rates down to 0.1ml/min. Don't know if this would work

Jonathan


Professor J.C. Knowles BSc(hons), PhD, FIMMM, CEng, FRSC, CSci
Professor of Biomaterials Science
Editor, Journal of Biomaterials Applications
Editor, Journal of Tissue Engineering
Head of Division of Biomaterials and Tissue Engineering,
UCL Eastman Dental Institute,
University College London,
256 Gray's Inn Road,
London WC1X 8LD. UK.
Tel [phone]
Fax [phone]
Mobile [phone]
Skype Me. Call name is jknowles_edi
Email [hidden email]
Eastman website; http://www.eastman.ucl.ac.uk
Personal website; http://www.homepages.ucl.ac.uk/~sfhvjck
This email represents the views of the sender alone and must not be
construed as representing the views of the Eastman Dental Institute. It may
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privileged document and copyright work. Its content should not be disclosed
and it should not be given or copied to anyone other than the person(s)
named or referenced above. If you have received this email in error, please
contact the sender.



-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On
Behalf Of Hana Uhlirova
Sent: 26 October 2010 14:43
To: [hidden email]
Subject: perfusion system

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Dear list,

Has anyone experiences with perfusion system for live cell imaging?
Particularly I need to rinse with two liquids of precise concentration. We
have a home-made closed system and have problems with air bubbles and mixing
of those liquids by loss of the concentration accuracy. Any tips how to
figure this out?

Thank you all.

Hana

Hana Uhlirova PhD
Laboratory of Optical Microscopy
Institute of Physical Engineering
Faculty of Mechanical Engineering
Brno University of Technology
Czech Republic  

[Craig Brideau]

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The pumps are the key.  Syringe pumps or the like are the most reliable, but
provide limited volume.  They are less likely to have air bubbles though.
Don't forget to account for the volume of your delivery tubing when you are
distributing solutions to your sample!
I have had some success with mini gear pumps for delivering about 2ml/min of
solution.  You have to prime the pump first and run it a bit to make sure
any air is out of the system first though.  Peristaltic pumps have similar
issues; run them a bit first to make sure any air is out of the lines.

Craig


On Tue, Oct 26, 2010 at 8:48 AM, <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> You could try an HPLC pump. These quite often meter more than one channel
> at
> flow rates down to 0.1ml/min. Don't know if this would work
>
> Jonathan
>
>
> Professor J.C. Knowles BSc(hons), PhD, FIMMM, CEng, FRSC, CSci
> Professor of Biomaterials Science
> Editor, Journal of Biomaterials Applications
> Editor, Journal of Tissue Engineering
> Head of Division of Biomaterials and Tissue Engineering,
> UCL Eastman Dental Institute,
> University College London,
> 256 Gray's Inn Road,
> London WC1X 8LD. UK.
> Tel [phone]
> Fax [phone]
> Mobile [phone]
> Skype Me. Call name is jknowles_edi
> Email [hidden email]
> Eastman website; http://www.eastman.ucl.ac.uk
> Personal website; http://www.homepages.ucl.ac.uk/~sfhvjck<http://www.homepages.ucl.ac.uk/%7Esfhvjck>
> This email represents the views of the sender alone and must not be
> construed as representing the views of the Eastman Dental Institute. It may
> contain confidential information and may be protected by law as a legally
> privileged document and copyright work. Its content should not be disclosed
> and it should not be given or copied to anyone other than the person(s)
> named or referenced above. If you have received this email in error, please
> contact the sender.
>
>
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[hidden email]]
> On
> Behalf Of Hana Uhlirova
> Sent: 26 October 2010 14:43
> To: [hidden email]
> Subject: perfusion system
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Dear list,
>
> Has anyone experiences with perfusion system for live cell imaging?
> Particularly I need to rinse with two liquids of precise concentration. We
> have a home-made closed system and have problems with air bubbles and
> mixing
> of those liquids by loss of the concentration accuracy. Any tips how to
> figure this out?
>
> Thank you all.
>
> Hana
>
> Hana Uhlirova PhD
> Laboratory of Optical Microscopy
> Institute of Physical Engineering
> Faculty of Mechanical Engineering
> Brno University of Technology
> Czech Republic
>

[Tim Feinstein-2]

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Dear Hana,

If your perfusion needs are precise enough then you may want to consider
mixing within the chamber as well as precise control of dispensing (I
agree that two syringe pumps, possibly converging in a Y junction just
before the chamber, may help with dispensing).  Mixing within a chamber
can create dramatic and unpredictable gradients at short time scales.  For
most applications these do not last long enough to be much of a concern,
but it sounds like you might want to keep it in mind.

One way to make consistent, reproducible perfusion gradients could be to
use a chamber that separates the perfusion input / output from the cells
using a permeable membrane that divides the closed-cell chamber
horizontally.  The original idea was to isolate perfused cells from shear
force, but it seems like restricting chaotic mixing to the upper 'chamber'
should also make smoother perfusion gradients.  Bioptechs makes one (no
commercial interest).

All the best,


Tim

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Dear list,
>
> Has anyone experiences with perfusion system for live cell imaging?
> Particularly I need to rinse with two liquids of precise concentration. We
> have a home-made closed system and have problems with air bubbles and
> mixing
> of those liquids by loss of the concentration accuracy. Any tips how to
> figure this out?
>
> Thank you all.
>
> Hana
>
> Hana Uhlirova PhD
> Laboratory of Optical Microscopy
> Institute of Physical Engineering
> Faculty of Mechanical Engineering
> Brno University of Technology
> Czech Republic
>

__________________
Timothy Feinstein, PhD
Postdoctoral Associate,
University of Pittsburgh Dept. of Pharmacology and Chemical Biology
BST W1301, 200 Lothrop St.
Pgh, PA  15261

[Martin Wessendorf-2]

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Dear Hana--

On 10/26/2010 8:42 AM, Hana Uhlirova wrote:

> Has anyone experiences with perfusion system for live cell imaging?
> Particularly I need to rinse with two liquids of precise concentration. We
> have a home-made closed system and have problems with air bubbles and mixing
> of those liquids by loss of the concentration accuracy. Any tips how to
> figure this out?

I don't know whether this would be suitable for your application, but
Craig Jahr's group at Oregon Health Sciences University has studied the
kinetics of drug effects on neurons (using patch-clamp) by rapidly
changing the solution the cells (or patches) are exposed to.  He will
make a pair (or more) of pipettes a few hundred microns in diameter that
each contain a different solution; the solutions are gravity-fed.  He'll
then change the bathing solution by rapidly moving the pipette to which
the cell is exposed.  I expect that there could be mechanical
disturbance due to the fluid flowing out of the pipettes, but it might
be worth a try.  One reference is: Lester RA. Jahr CE. Journal of
Neuroscience. 12(2):635-43, 1992 , but I'd suggest looking at more of
his papers since much of his work uses methods such as these.

Good luck!

Martin Wessendorf

--
Martin Wessendorf, Ph.D.                   office: [phone]
Assoc Prof, Dept Neuroscience                 lab: [phone]
University of Minnesota             Preferred FAX: [phone]
6-145 Jackson Hall, 321 Church St. SE    Dept Fax: [phone]
Minneapolis, MN  55455                    e-mail: [hidden email]

[Deanne Veronica Catmull]

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Hi Hana,

Try and place a bubble trap into your system and make sure it is placed
downstream of the pump, but before entry to the chamber. This should fix
that problem. Alternatively you could use a syringe pump instead of a
peristaltic pump which gives a much smoother flow.
As for the other problem, depending on the design you could be creating
"pockets" where liquids are not being exchanged as readily as in other
areas which will be a real nightmare when it comes to the analysis of
your images. Make sure there are plenty of entry points within your
chamber to allow the even passage of liquids through your system also.
This will ensure you achieve laminar flow. To know whether you are
achieving laminar flow you can calculate the Reynolds number for the
system. If it is under 2300, you have laminar flow.

Kind regards,
Deanne.

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]]
On Behalf Of Hana Uhlirova
Sent: Wednesday, 27 October 2010 12:43 AM
To: [hidden email]
Subject: perfusion system

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Dear list,

Has anyone experiences with perfusion system for live cell imaging?
Particularly I need to rinse with two liquids of precise concentration.
We
have a home-made closed system and have problems with air bubbles and
mixing
of those liquids by loss of the concentration accuracy. Any tips how to
figure this out?

Thank you all.

Hana

Hana Uhlirova PhD
Laboratory of Optical Microscopy
Institute of Physical Engineering
Faculty of Mechanical Engineering
Brno University of Technology
Czech Republic  

[Teng-Leong Chew]

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Hi Hana,

Mixing of liquid within the chamber is rarely accurate,
especially if you need the drug effect to kick in instantly
(since I don't know what you are working on, it is hard
to give precise recommendation).

Using peristaltic pump may also create "breathing" effect
as you are imaging. So your set-up should be in such a
way that the chamber is never connected to the pump
directly, but through a liquid reservoir that can help
dampen the breathing effect. Syringe pump works better
in this case.

There are a lot of microprocessor controlled, microfluidic
systems that you can buy if you have the cash. But I am
a happy Bioptechs customer (no $$ interest or connection).

--
Teng-Leong Chew, Ph.D.
Director, Cell Imaging Facility & Nikon Imaging Center
Director of University Imaging Resources
Feinberg School of Medicine & Office of Research
Northwestern University
303 E. Chicago Avenue
Chicago, IL 60611
[phone]
[phone] (W, F)

> Dear list,
>
> Has anyone experiences with perfusion system for live cell imaging?
> Particularly I need to rinse with two liquids of precise concentration.
> We
> have a home-made closed system and have problems with air bubbles and
> mixing
> of those liquids by loss of the concentration accuracy. Any tips how to
> figure this out?
>
> Thank you all.
>
> Hana
>
> Hana Uhlirova PhD
> Laboratory of Optical Microscopy
> Institute of Physical Engineering
> Faculty of Mechanical Engineering
> Brno University of Technology
> Czech Republic  

[Dan Focht]

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Hana


Perfusing a closed system chamber is not trivial.
When a fluid is enclosed in an optical cavity where one surface is a coverslip having an unsupported aperture you can easily notice any variation in flow as it translates to a Z axis shift in the specimen plane.

There are advantages and disadvantages to three basic methods of perfusion.

Gravity - inexpensive and you can get it anywhere!  It is hard to regulate in very slow flow rates but it sure is cheap!

Positive displacement pumps , such as a syringe pump - have limited capacity and as you increase its capacity by using a larger syringe you also increase the ratio of hydraulic flow in the tubing.  As frictional forces build and release themselves as the piston is pressed forward you will find that the larger piston can cause instantaneous high velocity advancement of the fluid flow that causes the coverslip to flex out of focus.  Therefore, you have to make sure the syringe size is both adequate for the duration of the experiment and not too large to cause the afore mentioned problem.  Also always make sure that the drive motor of a any pump used for microscopy applications is NOT a stepper motor.  The last thing you need is steps in your fluid flow!

Peristaltic pumps - Bioptechs has sampled every pump we have come in contact with to determine the best means of perfusion for microscopy.  We have what we call a microperfusion pump that is driven by a tachometer regulated DC motor with a multiple stage gear reduction.  This means that the motor is in continuous motion (without steps) and the output spindle can rotate extremely slow and smooth.  This pump has its own internal speed control and can also be controlled by an external reference voltage supplied by a USB interface and control program.  Flow rates are available from 0.02ml/hr to 180 ml/hr.   Note; this is not a perfect solution but it is the best means of controlled perfusion we know.
The only problem we have experienced with this pump is a small glitch that occurs when the captured flow in the pump head is allow to combine with the downstream flow that has exited the pump-head.  At the instant that the two fluid bodies combine, if there is a difference in preload and post load pressure, a "glitch" can be seen in the outflow.  other than that no problem.

Additional information available at:
http://www.bioptechs.com/Products/MPP/mpp.html

and for precise control of two perfusion supplies with the ability to control the effect of dead-volume and diffusion gradient:

http://www.bioptechs.com/Products/MPP/perftempctrl.html


If you have any further questions please call during U.S. eastern time 9:00 AM to 5:00 PM
Phones answered by live human beings.  We do not use answering machines during business hours.

There are other "tricks" to having a smooth flow through a closed system chamber on our web site.  See bottom of page:

http://www.bioptechs.com/Instructions/Co2_Renderings/co2_setup.html


Dan





On Oct 26, 2010, at 9:42 AM, Hana Uhlirova wrote:

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Dear list,

Has anyone experiences with perfusion system for live cell imaging?
Particularly I need to rinse with two liquids of precise concentration. We
have a home-made closed system and have problems with air bubbles and mixing
of those liquids by loss of the concentration accuracy. Any tips how to
figure this out?

Thank you all.

Hana

Hana Uhlirova PhD
Laboratory of Optical Microscopy
Institute of Physical Engineering
Faculty of Mechanical Engineering
Brno University of Technology
Czech Republic  

Dan Focht
Bioptechs, Inc.
3560 Beck Rd.
Butler, PA 16002
www.bioptechs.com
P: [phone]
F: [phone]
[hidden email]

[Jeremy Adler-3]

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The cyclical pressure changes produced by roller pumps will cause  
movement of the chamber and a change in focus.
This can be eliminated by (a) using a air filled side arm which damps  
the pulsations, as a been mentioned previously, and (b) by making the  
outlet port of the perfusion chamber much wider than the inlet port -  
something rarely seen in commercial perfusions.

Gravity provides pulseless driving force for perfusions and is quite cheap.

Jeremy Adler
Genetics & Pathology
Rudbeckslaboratoriet
Daghammersköljdsväg 20
751 85 Uppsala
Sweden

0046 (0)18 471 4607

[Craig Brideau]

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A few years ago one of our students needed non-pulsing flow for a perfusion
setup.  As an added catch, the perfusion had to run for over 20 hours, so
syringe pumps didn't have sufficient volume.  I managed to find a very tiny
gear pump that provided steadier flow and had enough head to feed from a
fairly deep reservoir jug.  Gear pumps basically trap small amounts of fluid
between the teeth of a pair of gears.  The flow from the pump is still
slightly pulsing but much better than a peristaltic pump.  The pump has been
used for a number of different projects over the years and is still working
well.

Craig


On Thu, Oct 28, 2010 at 1:14 AM, Jeremy Adler <[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> The cyclical pressure changes produced by roller pumps will cause movement
> of the chamber and a change in focus.
> This can be eliminated by (a) using a air filled side arm which damps the
> pulsations, as a been mentioned previously, and (b) by making the outlet
> port of the perfusion chamber much wider than the inlet port - something
> rarely seen in commercial perfusions.
>
> Gravity provides pulseless driving force for perfusions and is quite cheap.
>
> Jeremy Adler
> Genetics & Pathology
> Rudbeckslaboratoriet
> Daghammersköljdsväg 20
> 751 85 Uppsala
> Sweden
>
> 0046 (0)18 471 4607
>

[Boswell, Carl A - (cboswell)]

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An appropriate siphon system can provide constant flow for essentially
unlimited volumes.  This is a trick used by old (me) column
chromotographists, in which a large reservior is connected to the column (or
small feeding reservior) via a tube that loops lower than the bottom of the
column (or the perfusion chamber).  The pressure is determined only by the
height of the small reservoir.  Flow from the small reservior into the
chamber causes lower pressure to pull solution from the large reservior.  If
I remember correctly, as long as the connecting tube between the reservoirs
loops below the outlet (waste tube from the chamber) then flow (pressure) is
constant.  One can continue to replenish the large reservoir because there
is no disturbance of the small one.  An added bonus is it can never run dry
because when the large reservoir empties the flow stops when the liquid
level in the connecting tube reaches the same level as the outlet tube.

If you're interested, I could do a diagram.

c

Carl A. Boswell, Ph.D.
Molecular and Cellular Biology
University of Arizona
520-954-7053
FAX [phone]
----- Original Message -----
From: "Craig Brideau" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, October 28, 2010 9:03 AM
Subject: Re: perfusion system


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A few years ago one of our students needed non-pulsing flow for a perfusion
setup.  As an added catch, the perfusion had to run for over 20 hours, so
syringe pumps didn't have sufficient volume.  I managed to find a very tiny
gear pump that provided steadier flow and had enough head to feed from a
fairly deep reservoir jug.  Gear pumps basically trap small amounts of fluid
between the teeth of a pair of gears.  The flow from the pump is still
slightly pulsing but much better than a peristaltic pump.  The pump has been
used for a number of different projects over the years and is still working
well.

Craig


On Thu, Oct 28, 2010 at 1:14 AM, Jeremy Adler
<[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> The cyclical pressure changes produced by roller pumps will cause movement
> of the chamber and a change in focus.
> This can be eliminated by (a) using a air filled side arm which damps the
> pulsations, as a been mentioned previously, and (b) by making the outlet
> port of the perfusion chamber much wider than the inlet port - something
> rarely seen in commercial perfusions.
>
> Gravity provides pulseless driving force for perfusions and is quite
> cheap.
>
> Jeremy Adler
> Genetics & Pathology
> Rudbeckslaboratoriet
> Daghammersköljdsväg 20
> 751 85 Uppsala
> Sweden
>
> 0046 (0)18 471 4607
>

[Csúcs Gábor]

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Dear Carl,

I'd certainly appreciate a diagram as I can't completely imagine your
arrangement.

Thanks   Gabor

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> An appropriate siphon system can provide constant flow for essentially
> unlimited volumes.  This is a trick used by old (me) column
> chromotographists, in which a large reservior is connected to the
> column (or small feeding reservior) via a tube that loops lower than
> the bottom of the column (or the perfusion chamber).  The pressure is
> determined only by the height of the small reservoir.  Flow from the
> small reservior into the chamber causes lower pressure to pull
> solution from the large reservior.  If I remember correctly, as long
> as the connecting tube between the reservoirs loops below the outlet
> (waste tube from the chamber) then flow (pressure) is constant.  One
> can continue to replenish the large reservoir because there is no
> disturbance of the small one.  An added bonus is it can never run dry
> because when the large reservoir empties the flow stops when the
> liquid level in the connecting tube reaches the same level as the
> outlet tube.
>
> If you're interested, I could do a diagram.
>
> c
>
> Carl A. Boswell, Ph.D.
> Molecular and Cellular Biology
> University of Arizona
> 520-954-7053
> FAX [phone]
> ----- Original Message ----- From: "Craig Brideau"
> <[hidden email]>
> To: <[hidden email]>
> Sent: Thursday, October 28, 2010 9:03 AM
> Subject: Re: perfusion system
>
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> A few years ago one of our students needed non-pulsing flow for a
> perfusion
> setup.  As an added catch, the perfusion had to run for over 20 hours, so
> syringe pumps didn't have sufficient volume.  I managed to find a very
> tiny
> gear pump that provided steadier flow and had enough head to feed from a
> fairly deep reservoir jug.  Gear pumps basically trap small amounts of
> fluid
> between the teeth of a pair of gears.  The flow from the pump is still
> slightly pulsing but much better than a peristaltic pump.  The pump
> has been
> used for a number of different projects over the years and is still
> working
> well.
>
> Craig
>
>
> On Thu, Oct 28, 2010 at 1:14 AM, Jeremy Adler
> <[hidden email]>wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> *****
>>
>> The cyclical pressure changes produced by roller pumps will cause
>> movement
>> of the chamber and a change in focus.
>> This can be eliminated by (a) using a air filled side arm which damps
>> the
>> pulsations, as a been mentioned previously, and (b) by making the outlet
>> port of the perfusion chamber much wider than the inlet port - something
>> rarely seen in commercial perfusions.
>>
>> Gravity provides pulseless driving force for perfusions and is quite
>> cheap.
>>
>> Jeremy Adler
>> Genetics & Pathology
>> Rudbeckslaboratoriet
>> Daghammersköljdsväg 20
>> 751 85 Uppsala
>> Sweden
>>
>> 0046 (0)18 471 4607
>>

--
Gabor Csucs
Light Microscopy Centre, ETH Zurich
Schafmattstrasse 18, HPM F16
CH-8093, Zurich, Switzerland

Web: www.lmc.ethz.ch
Phone: [phone]
Mobile: [phone]
Fax: [phone]
e-mail: [hidden email]

[Asson-Batres, Mary Ann]

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Thank you.

________________________________________
From: Confocal Microscopy List [[hidden email]] On Behalf Of Carl Boswell [[hidden email]]
Sent: Thursday, October 28, 2010 1:42 PM
To: [hidden email]
Subject: Re: perfusion system

*****
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http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
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An appropriate siphon system can provide constant flow for essentially
unlimited volumes.  This is a trick used by old (me) column
chromotographists, in which a large reservior is connected to the column (or
small feeding reservior) via a tube that loops lower than the bottom of the
column (or the perfusion chamber).  The pressure is determined only by the
height of the small reservoir.  Flow from the small reservior into the
chamber causes lower pressure to pull solution from the large reservior.  If
I remember correctly, as long as the connecting tube between the reservoirs
loops below the outlet (waste tube from the chamber) then flow (pressure) is
constant.  One can continue to replenish the large reservoir because there
is no disturbance of the small one.  An added bonus is it can never run dry
because when the large reservoir empties the flow stops when the liquid
level in the connecting tube reaches the same level as the outlet tube.

If you're interested, I could do a diagram.

c

Carl A. Boswell, Ph.D.
Molecular and Cellular Biology
University of Arizona
520-954-7053
FAX [phone]
----- Original Message -----
From: "Craig Brideau" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, October 28, 2010 9:03 AM
Subject: Re: perfusion system


*****
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A few years ago one of our students needed non-pulsing flow for a perfusion
setup.  As an added catch, the perfusion had to run for over 20 hours, so
syringe pumps didn't have sufficient volume.  I managed to find a very tiny
gear pump that provided steadier flow and had enough head to feed from a
fairly deep reservoir jug.  Gear pumps basically trap small amounts of fluid
between the teeth of a pair of gears.  The flow from the pump is still
slightly pulsing but much better than a peristaltic pump.  The pump has been
used for a number of different projects over the years and is still working
well.

Craig


On Thu, Oct 28, 2010 at 1:14 AM, Jeremy Adler
<[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> The cyclical pressure changes produced by roller pumps will cause movement
> of the chamber and a change in focus.
> This can be eliminated by (a) using a air filled side arm which damps the
> pulsations, as a been mentioned previously, and (b) by making the outlet
> port of the perfusion chamber much wider than the inlet port - something
> rarely seen in commercial perfusions.
>
> Gravity provides pulseless driving force for perfusions and is quite
> cheap.
>
> Jeremy Adler
> Genetics & Pathology
> Rudbeckslaboratoriet
> Daghammersköljdsväg 20
> 751 85 Uppsala
> Sweden
>
> 0046 (0)18 471 4607
>

[Boswell, Carl A - (cboswell)]

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

To all who voiced an interest in the constant flow apparatus I mentioned on
the confocal listerv:

I've tried to draw up a diagram and in the process have come to realize I
don't remember it as well as I thought.  I will continue to work on it, and
if the revelation comes, I'll be sure to pass it on to you.  Isn't there
something about age and memory that is an inverse relationship?

cheers,
c

Carl A. Boswell, Ph.D.
Molecular and Cellular Biology
University of Arizona
520-954-7053
FAX [phone]
----- Original Message -----
From: "Asson-Batres, Mary" <[hidden email]>
To: <[hidden email]>
Sent: Friday, October 29, 2010 8:50 AM
Subject: Re: perfusion system


*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Thank you.

________________________________________
From: Confocal Microscopy List [[hidden email]] On Behalf
Of Carl Boswell [[hidden email]]
Sent: Thursday, October 28, 2010 1:42 PM
To: [hidden email]
Subject: Re: perfusion system

*****
To join, leave or search the confocal microscopy listserv, go to:
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*****

An appropriate siphon system can provide constant flow for essentially
unlimited volumes.  This is a trick used by old (me) column
chromotographists, in which a large reservior is connected to the column (or
small feeding reservior) via a tube that loops lower than the bottom of the
column (or the perfusion chamber).  The pressure is determined only by the
height of the small reservoir.  Flow from the small reservior into the
chamber causes lower pressure to pull solution from the large reservior.  If
I remember correctly, as long as the connecting tube between the reservoirs
loops below the outlet (waste tube from the chamber) then flow (pressure) is
constant.  One can continue to replenish the large reservoir because there
is no disturbance of the small one.  An added bonus is it can never run dry
because when the large reservoir empties the flow stops when the liquid
level in the connecting tube reaches the same level as the outlet tube.

If you're interested, I could do a diagram.

c

Carl A. Boswell, Ph.D.
Molecular and Cellular Biology
University of Arizona
520-954-7053
FAX [phone]
----- Original Message -----
From: "Craig Brideau" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, October 28, 2010 9:03 AM
Subject: Re: perfusion system


*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

A few years ago one of our students needed non-pulsing flow for a perfusion
setup.  As an added catch, the perfusion had to run for over 20 hours, so
syringe pumps didn't have sufficient volume.  I managed to find a very tiny
gear pump that provided steadier flow and had enough head to feed from a
fairly deep reservoir jug.  Gear pumps basically trap small amounts of fluid
between the teeth of a pair of gears.  The flow from the pump is still
slightly pulsing but much better than a peristaltic pump.  The pump has been
used for a number of different projects over the years and is still working
well.

Craig


On Thu, Oct 28, 2010 at 1:14 AM, Jeremy Adler
<[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> The cyclical pressure changes produced by roller pumps will cause movement
> of the chamber and a change in focus.
> This can be eliminated by (a) using a air filled side arm which damps the
> pulsations, as a been mentioned previously, and (b) by making the outlet
> port of the perfusion chamber much wider than the inlet port - something
> rarely seen in commercial perfusions.
>
> Gravity provides pulseless driving force for perfusions and is quite
> cheap.
>
> Jeremy Adler
> Genetics & Pathology
> Rudbeckslaboratoriet
> Daghammersköljdsväg 20
> 751 85 Uppsala
> Sweden
>
> 0046 (0)18 471 4607
>