|Urea transport in kidney brush-border membrane vesicles from an elasmobranch, Raja erinacea
Robyn L. et al,J. experimental biology, 206, 3293-3302, 2003; internal ref BB04
J. experimental biology, 206, 3293-3302, 2003; internal ref BB04 2003
|Comparison of microporous membrane morphologies using confocal scanning laser microscopy
Charcosset C (reprint), et al.
Journal of membrane science. 2000. v168, n2, p53-62 2000
|How do I clear my Millipore filters?||It is possible to clear Millipore filters by choosing a clearing agent with the same refractive index as the membrane. This is called the PORE FILLING TECHNIQUE. Filters appear opaque because of the diffraction of light through the tortuous pores. Filling the pores with a liquid that has the same refractive index as the membrane (ex. xylene for MF filters) allows light to pass through the filter at a uniform speed thus rendering the filter transparent. This technique can be used for most membrane filters with a single refractive index. The refractive index for Durapore membrane is 1.42 and for MF membrane its 1.50.
Please note that this does not work for polycarbonate membranes because these membranes have more than one refractive index (1.62 and 1.58). If desired, the porous structure can be dissolved from Isopore polycarbonates by dissolving the filter in chloroform, methylene chloride or 1-methyl-2 pyrrolidone.
|What is the blue separation paper between my filters?||It is a parchmentalized paper specially formulated for Millipore Corporation.|
|How do I tell the membrane from the separator?||The blue paper is the separator.|
|Which side of the membrane should I use, the shiny or dull side?||Most researchers may not even notice that there is a "sidedness" to filters, and, for most applications, orientation will not affect filter performance. However, membranes do have a slightly asymmetric pore structure: the shiny side of the membrane is the "tighter" side. In some applications, you can take advantage of this difference by selecting a specific filter orientation. ultrafiltration membranes should always be used shiny side up, regardless of application for drop dialysis ( a buffer exchange technique in which a few drops of DNA or protein are placed in a 0.05 or 0.025 um filter and floated on a buffer solution), apply the sample to the shiny side of the filter and float the filter dull side to the buffer. This measure will enhance buffer exchange and discourage sample loss. The Millipore Express and Express Plus membranees are also sided - these membranes should be used shiny side facing down.|
|What is the difference between pore size and pore size distribution?||Whereas pore size is a measure of the diameter of the largest pore, pore size distribution is a measure of the range of pore sizes. The range of pore sizes can be normally distributed, and the spread can be quite narrow (e.g. the ratio of largest to smallest may be less than 2). On the other hand, pore size distribution can be very heterogeneous. In the case of large spreads and heterogeneity, the pore size will be far less predictive of flow rate (either filtration or capillary) than it will be for a membrane with a narrow pore size distribution. It is important to note that the pore size corresponding to the bubble point is not at the middle of the distribution, but is the largest pore.|
|Is Polyvinylpyrolidone (PVP) toxic to cell growth on our Isopore membrane?||PVP coated membranes are not suitable and will not support the attachment of cells to the membrane. PVP in Millicell-PC membranes has been validated for hybridoma cell growth and subsequent antibody production and found to be non-toxic. PVP is generally considered non-toxic and for a while was used in vivo as a plasma expander.|
The Isopore membrane is a polycarbonate, track-etched screen filter recommended for all analyses in which the sample is viewed on the surface of the membrane. Isopore membrane offers distinct advantages for the analysis of airborne contaminants and other particles using optical or electron microscopy. The Isopore membrane is composed of polycarbonate film, which has a smooth, glass-like surface for clearer sample observation. The unique manufacturing process of the membrane ensures a precise pore diameter and a consistent pore size for accurate separation of samples by size. Isopore membranes do not stain resulting in low background interference. Clearing is not necessary for most transmitted light microscopy. Matched-weight filters are not usually required because of low, constant tar and ash weights. Isopore membranes are non-hygroscopic, which permits rapid drying and reduced sample analysis time.
The Isopore™ membrane is a polycarbonate, track-etched screen filter recommended for all analyses in which the sample is viewed on the surface of the membrane. Isopore™ membrane offers distinct advantages for the analysis of airborne contaminants and other particles using optical or electron microscopy. The Isopore™ membrane is composed of polycarbonate film, which has a smooth, glass-like surface for clearer sample observation. The unique manufacturing process of the membrane ensures a precise pore diameter and a consistent pore size for accurate separation of samples by size. Matched-weight filters are not usually required because of low, constant tar and ash weights.
Features & Benefits
- Membrane structure retains particles on the surface, simplifying counting and analysis
- Isopore™ membranes do not stain, resulting in low background interference
- Non-hygroscopic, allowing for rapid drying and reduced sample analysis time
- Translucent material does not require clearing for transmitted light microscopy; also available in brown variety
Air Monitoring, Epifluorescent Microscopy, Chemotaxis Assays
For more information visit: www.emdmillipore.com/filterdiscs
Color: white or brown**
Thickness: 7–22 µm
Sterilization: by autoclave (121 °C at 1 bar), EO or gamma*
Gravimetric extractables: < 1.0%
* Brown color may fade if autoclaved.
** Brown membranes are compatible with immersion oils, including Type B and Type F.
|Applications||Filter Code*||Color||Pore Size
|Water Flow Rate
|Air Flow Rate
|Chemotaxis, bioassays, cytology, air monitoring||VMTP||White||0.05||7.1||–||0.35|
|Chemotaxis, bioassays, cytology, air monitoring, SEM analysis, sterility testing||GTTP||White||0.2||3.5||6||1|
|Epifluorescent microscopy, particle monitoring, air monitoring||GTBP||Brown||0.2||3.5||6||–|
|Adsorbable organic halides (AOX), air monitoring, particle monitoring||HTTP||White||0.4||1.5||50||7|
|Epifluorescence microscopy, particle monitoring, air monitoring||HTBP||Brown||0.4||2||18||–|
|Reflective light microscopy, SEM analysis, gravimetric analysis, air monitoring||DTTP||White||0.6||0.6||25||10|
|Reflective light microscopy, SEM analysis, gravimetric analysis, air monitoring, asbestos monitoring||ATTP||White||0.8||0.6||40||10|
|Chemotaxis, bioassays, cytology, air monitoring||RTTP||White||1.2||0.6||110||20|
|Parasitology, chemotaxis, bioassays, cytology, air monitoring||TMTP||White||5||–||250||50|
|Chemotaxis, bioassays, cytology, air monitoring||TETP||White||8||–||250||60|
|*Corresponds to first 4 digits of catalogue number|