- High quality hi-tech
solution to venting culture vessels.
- Fully autoclavable.
- Very hydrophobic so prevents
passage of contaminating water splashes or aerosols in humid environment.
- Sub micron particle retention
- Increase air exchange
safely enabling rapid plant growth.
- Single or multilayer
of specially toughened PTFE with adhesive ring.
- Obtain expensive clean
room air quality at a fraction of the cost by venting each culture container
to the same standards of contamination control.
- PTFE technology
asked questions and information resource as applied to Adhesive Microfiltration
Discs (AMD) ) as supplied by TQPL.
Q. Why should
I vent my cultures?
air exchanges lead to increased plant growth in many in-vitro systems.
or reduce vitrification / glassiness / hyperhydricity.
- Remove or vent ethylene,
phenolic and other deleterious gasses
in-vitro environment leads to vigorous growth and better establishment
of plants out of culture.
- Achieve good aeration without
Q. Why should
I use PTFE?
Q. What is the pore size
if the PTFE used in Adhesive Microfiltration Discs?
- The pore size and PTFE structure
is sufficiently small enough to stop the passage of mites, dust, fungi,
yeast, bacteria and other microbiological contamination agents.
Q. Can I compare the pore
size with other filter systems?
Q. Where can I find a
supplier of Membrane Filters to vent my cultures?
Q. Why is hydrophobicity
important in the AMD?
Q. Will moisture ingress
- Generally AMD venting
does not allow inward passage of moisture from environmental dampness,
humidity or water splashes. Although not recommended it is possible
to store AMD vented cultures for short periods of time in humid
growing areas such as greenhouses without contamination loss, such cultures
should be watched carefully as standard laboratory procedure,
Q. Can I use PTFE venting
to eliminate contamination due to mites?
- Mite infestation of cultures
can be stopped by the use of our PTFE venting systems. Mites cannot
pass through the PTFE while the adhesive ring provides a strong mite
barrier. AMD has an especially strong and wide layer of 'miteproof'
adhesive. All non-venting points of entry for mites should be eliminated.
Q. Can I obtain technical
information about the use of AMD?
- We supply technical information
with orders and can be contacted with specific questions about our products.
We will always try and help based on our many years of experience in
PTFE venting. Our products can be used for a range of venting uses with
plant and cell culture systems. They can also be used for non in-vitro
Q. What is your experience
in PTFE venting?
- We first started using multilayered
PTFE venting systems over 20 years ago, and we believe we were the first
in the UK to introduce such technology to the commercial world of orchid
raising. We continue to use both AMD to vent cultures and achieve
optimum growth rates in the plants we produce.
Q. Why have we never heard
about Adhesive Microfiltration Discs, PTFE venting
- This is relative new technology
We have been selling PTFE venting systems since mid 1990's though
before then we kept such good ideas to ourselves and our commercial
Q. Can I obtain Adhesive
Microfiltration Discs (AMD) locally?
- We supply worldwide. We
are the only source of AMD's developed specifically for plant
micropropagation and flasking needs with the correct venting characteristics
for long term aseptic cultures. Purchasing direct from ourselves allows
savings on price and offers technical advice from within the in-vitro
industry. We do not have agents or intermediaries but supply direct
Q. Are all PTFE venting
systems the same?
- No, this is very apparent
as soon as you examine, compare or use our AMD. The AMD's are
uniquely laminated with a polymer layer. We consider many other products to be inferior to our own which were
manufactured according to our in-vitro requirements.
Q. I have seen some PTFE
vents curl up at the edges which makes them look fragile and unsuitable
and wonder if yours do this?
- This does not occur with
our product during normal usage. Our AMD's are strengthened with a strong polymer layer and respond well in flex tests,
Q. How can I ensure the
correct air exchange rate?
- This is affected by many
factors including the structures of the PTFE filter, the venting hole
size, along with the volume of the culture vessel. The growing room
conditions, the air flow over the discs and the phototranspiration.
The growth rates of the plants and plant type can all have an influence.
In addition the use of static or shaken cultures can determine the required
air flow demands for optimal growth. Correct balance of all these factors
should be aimed for or problems may occur. We can advise.
Q. Why do I need to optimize
air exchange for in-vitro cultures?
- Good air exchange allows
any depletion in carbon dioxide levels to be eliminated which is important
in photomixotrophic cultures (air-vented cultures with a sugar carbon
source in the media). The in-vitro environment is improved with the
diffusion of carbon dioxide and deleterious phenolic and ethylene gasses.
Many plants in-vitro are intolerant to these gasses.
- Good air exchange improves
the in-vitro environment allowing cultures to grow at maximum or optimal
growth. Culture time and plant growth needs to be optimized in many
systems for rapid turn around and competative economic considerations.
Q. Will good venting help
with establishment of plants out of culture in the nursery?
- Our experience has been
that survival of plantlets is improved when well vented and good air
exchange is achieved during culture. This may well be due to the 'hardening'
effect of evapotranspiration as plants grow photomixotrophically.
- Ratcliffe Orchids Ltd., can achieve 100% survival of Paphiopedilum
plants with no losses from flasks of seedlings vented with AMD or
Q. How many times can I
use Adhesive Microfiltration Discs?
- These AMD's are primarily
used in-vitro for single usage. This is to ensure aseptic integrity
and safety of valuable cultures. Quality control over the air exchange
rate for the life of the cultures or plants can be easily achieved by
single usage. This also overcomes problems with filter contamination
load over time which leads to reducing air flow rates. See below.
The 'disposable' price of these filters is often small compared to the
value of plants. We recommend single usage but on occasions where less
valuable stock is being grown repeated autoclaving can be tried as the
customers own risk and evaluated accordingly.
Q. What is filter contamination
- This is the entrapped debris,
particles and microorganisms removed during the process of filtration
from air or gasses passing through the filters. This increases over
time and use and is a factor of the external filtration environment.
An increased contamination load affects filtration efficiency, air flow
and increases potential contamination risk.
Q. How can I ensure the
best air filtration for my cultures?
- Single usage of AMD ensures optimal filtration efficiencies and quality control of filtration
Q. How can I stop contamination
from the air supply?
- If you ensure your containers
do not leak air or contamination and adopt AMD venting, with correct
autoclaving procedures, subsequent venting contamination can be eliminated
by the correct use of these PTFE venting systems.
Q. Why do I need to achieve
quality controlled venting?
- Uniform air exchange allows
uniform batch growth of cultures and improves the quality control of
plants. This is especially important where either rapidly growing cultures
are being grown by either liquid or solid culture batch techniques.
Long-term in-vitro cultures also need to optimize growth conditions
to allow uniform growth. Any limiting factor will become exaggerated
Q. I normally use cotton
wool to vent my cultures, should I change?
- The principle disadvantages
with using cotton wool, is possible contamination risk. Liquids can
leak in both directions carrying contamination or inviting it in - even
with non-absorbent cotton wool. Uneven air flow occurs between different
bungs and flasks - according to how firmly the cotton wool has been
plugged. Good practice requires the use of hazardous chemicals and a
required 'cotton wool depth' of at least 1 inch to eliminate contaminating
agents. It is often necessary to further cover the cotton wool with
foils or polythene films.
- Shipping in-vitro can cause
problems with rapid air inflow using cotton wool.
Q. I have seen disks stuck
to flasks that look like discoloured medical bandaged are these PTFE?
- Some orchid flaskers use
medical bandages to vent their flasks. These suffer from discolouration,
and often need to be applied both internally and externally. They are
not PTFE vents, and suffer from clogging and swelling fibers over time
- leading to a drop off in efficiency of air flow and filtration. Our
PTFE vents are glistening white!
Q. Will I have to drill
a hole in my containers before applying an AMD?
- You will have to drill a
hole, and the diameter is critical, we can advise with orders if requested.
For a clean hole in plastic we advise the use of an electric drill with
metal cutting drill bit. Information sheets provided give details of
Q. Can AMD be used with
rubber bungs or Kimax rubber closure lids?
- Yes, we can advise, and
by this means risks of moisture ingress can be eliminated and quality
controlled hydrophobic venting adopted.
Q. What other uses can PTFE
venting discs be put to?
- Our discs can be used for
a variety of different uses other than in-vitro venting. There are many
industries where sub-micron particle retention is required to eliminate
particles from air or gas passage They can also be used to provide a
route to equalize pressures. Their hydrophobic nature means they have
uses with moisture sensitive equipment. The unique use of an adhesive
makes these discs very versatile.
- If you wish to discuss this
please contact us and we are only too willing to advise if we can.
Q. Can Adhesive Microfiltration
Discs be used for carbon dioxide enrichment studies?
- The growth of plants by
photoautotrophic micropropagation and a high carbon dioxide concentration
is a developing field. These provide an alternative to fragile gas-permeable
films and at present are being evaluated by the leading scientists in
the field at Chiba University, Japan. We have supplied leading reasearchers around the world.
Q. Are there alternative
methods than an autoclave for sterilizing the AMD ?
- These discs can
be sterilized using gamma radiation, a suitable ultraviolet source or
ethylene oxide gas sterilant.
- It is important that all the internal microfilbrils are rendered sterile for clean air to flow for the life of the filter discs.
- They cannot be sterilised by mircrowave or chlorine solutions.
Q. Can I ship my cultures
by air carrier without contamination?
- Yes, our
PTFE discs provide a safe way to vent cultures for air travel, where
pressure changes make it vitally important that a reliable system is
used. This is especially important where using a non-rigid container
or flask. Without venting such containers will distort and blow the
lids off. For flexible containers we recommend the AMD to ensure the
best integrity and arrival of cultures intact and aseptic integrity
- Our Plant Culture Containers
weigh only 19gms so provide an excellent option for international shipping
and with AMD fitted have proved completely safe for transporting plants
in-vitro around the world. We have no contamination losses from such
transport systems. There is no need for any additional taping or sealing
as the lids are snap secure.
Q. Can germplasm be stored
at reduce temperature with reduced venting?
- Experience has shown that
the AMD's can be adapted to such techniques without problems sometimes
associated with dehydration of media or drying out of plant material.
Q. Can long term cultures
such as orchids be safely vented for many months?
- Yes. PTFE venting with AMD's
is an ideal approach and has many advantages compared to conventional
venting. Our experience with this crop is that aseptic integrity is
safe and venting for periods of 18 months can readily be achieved.
Q How many times can I autoclave
PTFE discs such as the AMD?
single usage for optimal venting and quality control. However the
AMD consist of material that can be repeatedly autoclaved.
PTFE, polymer, and the adhesive are all repeatedly autoclavable.
We would not advise removing the discs between autoclaving as this
will damage the integrity of the PTFE and adhesive. We would advise
to proceed with caution if such an approach is adopted. Some of our customers
report repeated use with success.
See comparative information
on Flasking Patches and Adhesive Microfiltration Discs to be found at
Modern Approaches to Venting at Modern Venting Systems now updated
- click here
Instructions for use of products
supplied with goods
Order PCC's from
TQPL by Phone, fax or e-mail.
to contact TQPL
/ Brookside / Southern Lane / New Milton / Hampshire / BH257JE / United
01425 616 608 / Int. +44 1425 616 608 / e-mail to: email@example.com
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