I m not sure but have a look at this website:

http://www.biocoat.com/hydakkits.htm

No, those are plates. We need transwell filters, like these: http://scientiis.com/laboratorium/catalog/images/Laboratory/T-3412-12.jpeg

Hi Jason, try this site www.ibidi.de

I attended a microscopy course last June where they made a presentation and the products were great, with a lot of applications....and they send samples! Hope you find the filters there as well.

Hello Jason,

maybe you use a syringe with a filter like these: http://www.baxa.com/oem/images/products/Syringe_Filters.jpg those filters are avaible with 0,2 um or did you think the shearing forces are to strong for the cells?

Hello Jason again,

maybe you also can use nitrocellulose like these: http://www3.bio-rad.com/WWMSDS/LSGC/DE/DE_ENG_1620071.pdf ?

Corning has polycarbonate filters with pore sizes of 0.1µm available

Corning has discontinued the 0.1 filters. Despite the information in the Nunc catalogue, they have discontinued the entire Anopore line. I have talked to all major manufacturers (Millipore, Whatman, BD, Corning, Costar - all have discontinued all transwell filters with pore size below 0.4 micron.

We have 0.4 micron transwell filters (all the vendors still make these), but the pore size is too large.

Its for a transwell cell culture assay using bacteria, but the bacteria can pass through a 0.4 micron filter (which does not allow us to keep them separate in our assay). They will not pass through a 0.22 micron filter.

Jason,

as I write, maybe this two hints from me above helps.

I search now for about 1 hour, you are right. All datasheets etc. with 0,22 um are really old and not actually.

Maybe you should asked http://www.thermoscientific.com/ or http://www.invitrogen.com

Hi Sven,

Thanks. ThermoScientific owns Nunc - I spoke to them already. Invitrogen makes reagents for the transwell assay, but doesn't sell the transwell inserts themselves.

Ok Jason,

then I don't know where you also can search. Sorry. Please inform us when you find such inserts.

Greetings from germany,

Sven

Hi Jason, you can try Corning catalog No 8160 or 8161, These are spinx tube with cellulose acetate filter of 0.22 um, as you want to do experiment with bacteria, i suppose you can do experiment in polypropylene tube provided along with column. If you will suggest exact experiment, may be i can help you in designing of experiment.

with regards

Vibhu Jain, PhD

Hi Vibhu,

Yes thanks. We have these already and have considered them. They work, but they're clunky, its difficult to do high throughput assays with them (we have hundreds of assays to perform, which is much easier in plate format) and they are expensive for the number that we will need.

Thanks to everyone who replied. I think we are going to have to fabricate transwell inserts with the proper specifications ourselves.

Jason, how many plates you are looking for buying with such membrane, i understand handling so many tubes is not good choice.

If you need good number of 96 well plates with 0.22 um size, may be i can help you getting this product fabricated

Vibhu, what constitutes a "good number"?

Just give fair idea of plates you want to buy, I am not sure what is the number of plates which can attract someone to fabricate it. but i can try it

Costar

Http://vwrlabshop.com/costar-brand-transwell-inserts-polyester-sterile/p/0013566/

Louiza, Costar has discontinued the inserts we need (0.22 micron or smaller). Arvind, if you look at that website, you will see that the smallest pore size offered is 0.4 microns.

I think Vibhu has the best suggestion. Either we make these ourselves in the lab (we can purchase the filter material) or we have them custom manufactured.

May you please mention the application that requires such low pore-size ?. Is still related with cell culturing ?. The HT application is related to adherent cultures or you are handling suspension cells as well ?. I mean, very small-sized cells.

As I said above, we are performing a transwell assay with bacteria that can pass though a 0.4 micron filter but not a 0.22 micron filter.

Why not you are not able to use that 0.2um filter normally being used for filtrating culture medium?

Dear Jason,

I suggest you contact Epithelix as they have been useing culture inserts for many years for commercial purposes. They may certainly help you.

see http://www.epithelix.com/index.php?lang=en

Hope this helps,

Best regards

Jacques Bauer, OM Pharma, Meyrin, Switzerland

HI Samuel, we're performing a transwell assay, not filtering media.

Thanks Jacques, I'll follow up on that.

Hi Jason, I means that you may use the membrane of 0.2um filter which is within filter. The material may be coated with gelatin and/or other matrix proteins.

Hi Samuel,

Yes, which means we will have to make these ourselves. We'll do it if we have to, but if I can purchase them ready-made then its easier and more standardized.

Hi Jason,

Fabricating same in lab might lead to issue in membrane integrity.

HI Vibhu, we're well aware of that - that's why we're trying to find a commercial source.

Hello Jason,

me again. I know that you have talk to Millipore before, but did you know these table: http://www.millipore.com/membrane/flx4/millipore_filters_hm&tab1=1#tab1=1 maybe it helps you also.

And here this, maybe not avaible: http://www.labsource.com/Catalog/Item.aspx?ItemID=1140663

Hi Sven,

If those are autoclavable (they're not sterile) they may be perfect. I'll call millipore.

Thanks!

i thought of Millipore, one can use durapore membrane filter plate for application, but they are lousy for application Jason is lookinfg for, because

1.Filters are not seperate in such was that can be used as insert in well but can be kept on top of plate

2. filters are usually set on one mat and can cause contamination if not handles with care.

These cant be substitute of transwells

Hello Jason,

any news?

Jason?

Sorry,

No, we never found a source for these. We are using filtered bacteria culture supernatant instead, which seems to be working adequately.

Thanks for your answer!

Nunc has 0.2um and 0.02um tissue culture inserts

HI Luciana,

Thanks for the note. We've solved our issues. But FYI, Nunc does not carry these anymore - although they may still be listed in catalogues etc... they have been discontinued.

Thanks Jason

Hi Jason,

Could you share how did you solve this question to us? Thanks!

Hi Sam, as I stated above, we are just using filtered culture supernatant now and gave up co-culturing.

Jason, Do you have any idea why these filters were discontinued?

Presumably they didn't sell well enough.

had the same problem few years later, found this:

http://www.sigmaaldrich.com/catalog/product/sigma/m9535?lang=en®ion=SI&cm_sp=Insite-_-prodRecCold_xorders-_-prodRecCold2-2

https://www.carlroth.com/en/en/Labware/Filtration%2C-Water-Purification-and-Dialysis/Centrifuge-filter-systems/Centrifuge-filter-systems-Midi/p/000000020002f14100030023_en

Thanks for the tip. We used Nunc before and they were great. The regular inserts work OK but the bacteria get out after 24h.

I have the same problem now. Can anyone provide me with a good protocol to fabricate those transwells with the 0.2um filter membranes?

Nobody in the EU and nobody in the USA. You may ask somebody to custom-make your inserts and then sterilize them yourself. As an alternative, you may look up microconcentrators from Merck. They have much smaller pores but do not fit into standard wells.

Thank you for clarification.