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Polycarbonate (PCTE) Membrane Filters, 20.0 Micron, 47mm, 100/Pk

Polycarbonate Track Etch (PCTE) membranes are made from a thin, microporous polycarbonate film material. It is ideally suited for use in blood assays and high-purity and general filtration.

SKU
1270175
Manufacturer
Sterlitech
Pore Size
20.0
Diameter (mm)
47
Pack Size
100

Details

Polycarbonate (PCTE) Membrane Filters, 20.0 Micron, 47mm, 100/Pk

Hydrophilic PCTE Membrane Filter Applications

0.01 - 0.1 micron

  • Most liposome extrusions (range 0.03 - 0.4 µm)
  • Asbestos (water)
  • Bacteria removal: Acholeplasma laidwaii
  • Removal of colloidal material from water
  • Mycoplasma removal
  • Tissue culture with collagen: skin graft
  • Virus filtration

0.2 - 1.0 micron

  • 0.2 µm: General sterile filtration, sterile filtration of corrosive fluids, immunology, implant tissue and cell studies, air venting, aqueous fluids, air and gas sterilizing. FITC stain technique, Legionella pneumophilia - air conditioning water, DNA fragments filtration, phytoplankton, bacteria removal, deionized water-clinical laboratory Type 1 and for semiconductor industry using SEM analysis, and EPA leachate/toxicity testing.
  • 0.4 µm: Sterility testing, pulp, paper-adsorbable organic halides-water (AOX), air (asbestos fibers, silica particles pollen), dewatering, purification of cellular suspensions and wine stabilization, immunology - tissue and cell stuides, forensic analysis (SEM), microscopic examination - samples, Water-pollution (Escherichia coli), trace metal analysis (USGS method), nitrates, nitrites, phosphates, and ammonia (low extractable), particle analysis of corrosive fluids, bacteria - Serratia marcescens, and cell culture.
  • 0.6 µm: Particle analysis (corrosive fluids), analysis of wine, milk, cells and plasmapheresis.
  • Latex Agglutination Assays
  • 0.8u µm: General air analysis (asbestos, Cadmium), sugar molds (food), gravimetric analysis, tissue culture partitioning, wine stabilization, alkaline elution (DNA).
  • 1.0 µm: Serum pre-filtration, beer stabilization, ultracleaning (corrosive fluids), microfiltration (alcohol solutions), Giardia lamblia (removes most of them), red blood cells (RBC)
  • (0.2-0.8 µm): EPA leachate/toxicity testing.
  • (0.4-3.0 µm): Cell culture
  • (0.6-1.0 µm): Plasmapheresis

2.0 - 30.0 micron

  • 2.0 µm: Chemotaxis, alkaline elution (DNA), red blood cells (RBC's)
  • 3.0 µm: General microfiltration and clarification, cytological evaluation (cerebrospinal fluid), chemotaxis, red blood cells (RBC), microfiltration of corrosive fluids
  • 5.0 µm: Exfoliate cytology, chemotaxis, gravimetric analysis, Gairdia lamblia (3-5um) observation, canine heartworm microfilariae (dirofilaria immitis), erythrocyte deformability (4.7 µm), gross particulate analysis of corrosive fluids (oil, diesel, gas filtration)
  • 8.0 µm: Cytology
  • 12.0um: Starch, Schistosoma haematobium
  • (0.4-3.0 µm): Cell culture
  • (8.0-14.0 µm): Larger bacteria, general clarification and pre-filtration of corrosive fluids, most acides, some ester photoresists, reagent grade chemicals and alcohol solutions
  • (10.0-12.0 µm): Human melonoma invasion study (cancer-tumors), leukocytes, metastasis tumor cell
  • (0.01-20 µm): Scanning electron microscopy (SEM)

 

Sterlitech offers two versions of the pigmented PCTE membrane filters to cover the broadest possible range of potential applications: Gray and Black. 

Gray Membranes

Fluorescence Microscopy

Conventional Optical Microscopy

Black Membranes

Fluorescence Microscopy

Automated Fluorescence Microscopy

Optical Microscopy Studies of light colored particles/microorganisms

 

 

PCTE Membrane Filter Specifications

General

USP Class VI Testing Passed
BSA Protein Binding ~5 μg/cm2
Sterilization Gamma Irradiation, EtO
Max. Operating Temp 140 °C (284 °F)
Sealing Compatibility Ultrasonic, Heat, Radio Frequency, and Insert Molding
pH Range 4-8
Burst Strength 0.7 bar (10 psi)

 

Performance by Pore Sizea

  Pore Densityb
(pores/cm2)
Open Area
(%)
Nom. Weight
(mg/cm2)
Nom. Thicknessc
(µm)
Bubble Pointd
(psi)
Water Flow Ratee
(mL/min/cm2)
Air Flow Ratef
(L/min/cm2)
0.01 µm 6 x 108 <1 0.7 6 NA 0.1 0.0075
0.03 µm 6 x 108 <1 0.7 6 NA 0.2 0.075
0.05 µm 6 x 108 1 0.7 6 50 0.4 0.37
0.08 µm 4 x 108 2 0.7 6 38 0.6 0.75
0.1 µm 4 x 108 3 0.7 6 30 2.5 1.5
0.2 µm 3 x 108 10 1.1 10 20 10 3
0.4 µm 1.5 x 108 19 NA 24 12 45 7.5
0.6 µm 3 x 107 8 1.0 9 9 60 7.5
0.8 µm 3 x 107 15 0.9 9 7 90 19
1.0 µm 2 x 107 16 1.1 11 6 130 20
2.0 µm 2 x 106 6 1.1 10 3 300 16.5
3.0 µm 2 x 106 14 0.9 9 2 440 37.5
5.0 µm 4 x 105 8 1.1 10 1.2 700 30
8.0 µm 1 x 105 5 0.8 7 0.7 1000 30
10.0 µm 1 x 105 8 1.1 10 0.5 1150 34.5
12.0 µm 1 x 105 11.3 - 14 - - -
14.0 µm 5 x 104 8 0.6 6 0.2 1400 63.5
20.0 µm 5 x 104 13 - 32 - - -
25.0 µm 1 x 104 5 NA 25 <1 >1000 33
30.0 µm 1 x 104 7 NA 30 <1 >1500 50
 
Pore  Size (µm) Thickness (µm) Porosity
(%)
Bubble Point  Nominal Pore Density cm2 

indicative values
L/min/cm2 @0.7bar

Airflow rate

indicative values
ml/min/cm2 @0.7bar

Water flow rate

0.2µm 25µm   15.70% >3.5bar  5.00 E+08 >2 >10
0.4µm 25µm 18.80% >2 bar  1.50 E+08 >4 >30
0.8µm 24µm 20.10% >0.6 bar  4.00 E+07 >8 >80
1.0µm 24µm     2.20 E+07    
5.0µm 21µm 7.90%   4.00 E+05 >25 >500
8.0µm 18µm     1.00 E+05    
 
*Notes:
a. Tolerance + 0%, -20%
b. Tolerance +/-15%
c. Tolerance +/-10%
d. Measured using isopropanol (IPA)
e. Initial flow rates using prefiltered water at 10 psi (0.7 kg/cm2)
f. Initial flow rates using prefiltered air at 10 psi (0.7 kg/cm2) for pore sizes <= 2 µm and 5 psi (0.35 kg/cm2) for pore sizes >= 3 µm

Documentation / Media

PCTE Membrane Data Sheet

Frequently Asked Questions


The pores of microporous membrane filters act as small capillaries.  When hydrophilic membranes come into contact with water, capillary action associated with surface tension forces causes the water to spontaneously enter and fill the pores.  In this manner, the membranes are easily wetted and allow the bulk flow of water through the pores.  Once wetted, hydrophilic membranes will not allow the bulk flow of air or other gasses, unless they are applied at pressures greater than the membrane’s bubble point.

Hydrophilic membrane filters are typically used with water and aqueous solutions.  They can also be used with compatible non-aqueous fluids.  Hydrophilic membrane filters are typically not used for air, gas or vent filtration since the filters would block flow if inadvertently wetted, by condensation for example.

When hydrophobic membranes come into contact with water, surface tension forces act to repel the water from the pores.  Water will not enter the pores and the membranes will act as a barrier to water flow, unless the water is applied at pressures greater than the membrane’s water entry pressure.  Low surface tension fluids, such as alcohols, can spontaneously enter and fill the pores of hydrophobic membranes.  Once all the air in the pores is displaced, there are no longer any surface tension forces and water can easily enter the pores, displace the low surface tension fluid, and pass through the membrane.  The membrane will then allow bulk flow of water for as long as the pore remain water filled.  If the membrane is allowed to dry (i.e. air enters the pores), then it must be pre-wet with a low surface tension fluid again prior to use with water.

Hydrophobic membrane filters are typically used with compatible non-aqueous fluids.  They are also commonly used as air, gas, or vent filters.  Hydrophobic membrane filters are sometimes used with water or aqueous solutions; and, in these applications, they must first be prewet with a low surface tension, water miscible fluid prior to use.

Q. What is a Polycarbonate or Polyester Track Etch filter membrane?

A. These types of filter membranes are precise, two-dimensional micro porous screens with straight through, cylindrical pores.

As in the case of other screen-type filters, particle capture takes place only on the surface, therefore there is more accurate separation cut-off. The precision cylindrical pores of Track Etch membranes have the most accurate size cut-off of any membrane. In depth filters, particles get caught throughout the torturous paths within the matrix as well as on the surface of the membrane.

Track Etch filters are also very thin (between 6 - 15 microns thick) but very durable (can withstand over 3,000 psi when properly supported).   They range in color from opaque to almost transparent and black.

Q. What are the benefits of using Sterlitech Polycarbonate or Polyester filter membranes?

A. Sterlitech Polycarbonate Track Etch (PCTE) and Polyester Track Etch (PETE) filters offer the lowest, non-specific binding of any filter membrane. The capture of samples occurs on a flat, glass-like smooth surface with an even distribution of particles captured on a single plane, simplifying microscopic and SEM examination of samples captured on the surface of the membrane.

  • Sterlitech Track Etch filter membranes are manufactured and produced under class 100 condition during critical manufacturing steps. Therefore, the membrane is free of contaminants and pyrogens.
  • Sterlitech PCTE and PETE membranes offer very low extractables. Both PCTE and PETE membranes are integral, plastic films, therefore, there is no sloughing or particle shedding.
  • Sterlitech PCTE and PETE membranes are biologically inert. 
  • Both filter membranes offer excellent chemical resistance and thermal stability, with PETE offering a higher chemical resistance.

Polycarbonate track-etch (PCTE) membranes are inherently
hydrophobic.  The hydrophobic PCTE
membrane filters shown at https://www.sterlitech.com/hydrophobic-polycarbonate-membrane-filters.html do not have any wetting agents.  Before use in water or aqueous solutions, these filters are usually pre-wet with a compatible low surface tension, water miscible fluid such as a low molecular weight alcohol. 

The hydrophilic PCTE membrane filters shown at https://www.sterlitech.com/hydrophilic-polycarbonate-membrane-filters.html are treated with a wetting agent to render the membrane hydrophilic.  The wetting agent consists of a few molecular
thicknesses of polyvinylpyrrolidone (PVP) deposited on the membrane
surfaces.  The hydrophilic PCTE membrane filters can be used in water or aqueous solutions without pre-wetting.

Depending on the cell line, most exfoliated human cells adhere with some tenacity. Most epithelial cells will adhere if the membrane has a negative charge applied by gas plasma or has a suitable attractant applied to the surface of the membrane. Endothelial cells will generally not attach to the surface of Track Etch membranes.

There is a visually apparent difference between the sides of some of the PCTE membrane filters.  This is a result of the process used to manufacture the polycarbonate base film.  One side of the film has a very smooth surface resulting in a shiny appearance.  The other side has an inherent surface texture resulting in a dull or matte appearance.  The difference is purely physical; both sides are chemically the same.  Filter orientation does not affect particle retention.  For applications involving microscopic analyses of captured particles or microbes, most users prefer to orient the disk filter so that the smooth shiny side is facing upstream.

Yes, in some cases within manufacturing capabilities, Sterlitech can provide track-etch membrane filters with non-standard custom specifications for pore diameter, pore density, membrane thickness, and surface treatments.  Please contact us at [email protected] to discuss your application and to inquire about availability.

Q: Why are black dyed polycarbonate track-etch (PCTE) membrane filters preferred for use in epiflourescence microscopy?

A: Black dyed PCTE membrane filters provide the same advantages as regular PCTE membrane filters for microscopy applications, but also have exceptionally low autoflourescence. This permits high contrast between flourescent stained microorganisms and the dark surface of the membrane filters.  The very low autoflourescence of the black dyed PCTE membrane filters also makes them suitable for applications that use automated detection of flourescently labeled microorganisms such as laser scanning cytometry.

The polycarbonate track-etch (PCTE) membrane filters are quite thin and translucent.  Depending on pore size rating and pore density, the filters may appear transparent or may appear opaque.  Please review https://www.sterlitech.com/blog/post/clarifying-the-matter-of-polycarbonates-membrane-clarity.  In some instances, when PCTE membrane filters with standard specifications appear opaque, Sterlitech can provide custom low pore density filters with the same pore size rating that are transparent.  For comparison, most conventional microporous membrane filters are considerably thicker and cannot be made transparent.  Please contact us at [email protected] to discuss your application and to inquire about the availability custom PCTE membrane filters.

When performing microscopic studies of particles or cells resting on the surface of PCTE membrane filters, some users may find the appearance of the pore edges to be a hindrance.  There are some strategies that can be employed to reduce the appearance of the pore edges.  One of the simplest strategies is to dissolve the membrane, with chloroform or toluene for examples, leaving behind the particles.  Additionally, using a combination of wetting the membrane with a liquid that has the correct refractive index and illuminating the membrane with polarized light, it is possible to make the pores invisible.  The PCTE membrane is birefringent and has two refractive indices, 1.584 and 1.625.  To make the pores invisible, the membrane is wetted with a fluid that has a refractive index of 1.584 and is illuminated with properly oriented polarized light.

The polycarbonate track-etch (PCTE) membrane filters can be dissolved with dipolar aprotic solvents such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and n-methyl-2-pyrrolidone (NMP).  The PCTE membrane filters can also be dissolved with the organic chlorinated solvents dichloromethane (DCM or methylene chloride) and trichloromethane (TCM or chloroform).  PCTE membrane filters can also be dissolved with toluene and potentially with other similar aromatic hydrocarbon solvents.

The polyester track-etch (PETE) membrane filters can be dissolved with m-Cresol, o-Chlorophenol, hexafluoroisopropanol, and trifluoroacetic acid (TFA).

Both types of track-etch membranes can be dissolved with elevated temperature sodium hydroxide solutions.

Membranes are used in the study of white blood cell reactions to toxins (chemotaxis), to determine the natural immunity in whole blood. Since immunity is transferable, this could lead to the development of vaccines for treatment of cancer and other diseases. Membranes may be polycarbonate, with or without polyvinylpyrrolidone (PVP). It depends on the type of cells used. Apparently, Neutrophils have a tendency to round up and fall off the membrane when around PVP - not so with some of the other types of cells. Refer to each procedure. Characteristics of PCTE Membrane and Advantages in Chemotaxis Studies Uniform Properties yield reliable, consistent, and reproducible results. Less cell distortion for improved morphology.
Zero leaching of offensive surfactants yields reliable, consistent, and reproducible results.
Smooth, flat surface contributes to high cell visibility on proximal and distal surfaces. Improved morphologic resolution. Easy removal of excess cells from proximal surface.
Thinness of the membrane allows shorter incubation time. More assays made faster and simpler. Chamber sterilization not needed for most studies. Facilitates study of slower moving cells (e.g., monocytes and macrophages).
Low adsorption and absorption of cells causes higher yields. Enhanced radiometric analysis.
Non-staining results in improved contrast. Simplifies optical microscopic analysis routine.
Transparency simplifies optical microscopic analysis routine.
Heat sealable characteristics aids in experimenting with disposable chambers.
Strength of membrane means that less critical handling techniques needed.
Coating Membranes with Gelatin Wash membrane with 0.5% Acetic Acid.
Make a stock gelatin solution with 50mg/10mL water.
Working solution is 1-mL stock to 1-liter water for a light coating.
Then the membranes are placed in a rolling boil of this solution in a beaker for 1 hour.
The membranes are individually pulled out and placed on filter paper to air dry. If an oven is used, use very low temperature for 20 minutes. Air-drying is best in a covered dish left over night. Keep clean.
When the membranes are dry, place them back in their original box.
NOTE: For Chemotaxis, the most important issue is to keep everything at 37 degrees C., the water bath, buffers, glassware, etc. for 1 hour. Studies in cold produce cells that "round up", curl up and fall off. 

Q. What is the difference between nominal and absolute pore size ratings?

Nominal pore size ratings are provided as a general indication of filter retention.  It is understood that some quantity of particles greater than, and equal to, the nominal pore size ratings will pass through the filters into the filtrate.  Some manufactures may associate nominal pore size ratings with percentage filtration efficiencies. Nominal pore size ratings vary from manufacturer to manufacturer and, consequently, are not necessarily equivalent. Filters from different manufactures with similar nominal pore size ratings may not actually exhibit similar retention characteristics.

Absolute pore size ratings are typically based on retention studies performed using challenge suspensions of standard microorganism cultures or particles of known size. Absolute pore size ratings represent the size of the smallest microorganisms or particles completely retained during these studies. Absolute pore size ratings are almost always correlated to bubble point specifications that are used for quality control during membrane manufacturing. For the most part, absolute pore size ratings, especially those based on microbial retention, are comparable from manufacturer to manufacturer. There is more uncertainty for absolute pore size ratings based on particle retention studies, especially for pore size ratings <0.2µm, since there are no standard methods for these studies.

Regardless of pore size ratings, it is important to understand that application conditions do influence particle retention. Even filters with absolute pore size ratings can be operated in conditions that will allow unexpectedly sized particles to pass.


The pore size refers to the diameter of the individual pores in a membrane filter.   Pore size is typically specified in micrometers (µm).   Most membranes and filter media actually contain a distribution of pore sizes.  Nominal pore size ratings typically refer to the predominant pore size of a filtration media; pores larger and smaller than the nominal rating may be present.  Absolute pore size ratings typically refer to the largest pore size of a membrane and it is expected that all pores will be equal to or smaller than the absolute rating.

For the polycarbonate track-etch (PCTE) and polyester track-etch (PETE) membrane filters, porosity is the percent of the total surface area occupied by the pores; it typically ranges from <1% to 16%.  For the other membrane filters, porosity is the percent of the total volume occupied by the pores; it typically ranges from 40 to 80%.

You can find the Sterlitech compatibility guide.  It is important to realize that application conditions, such as operating temperature, affect compatibility.  Please contact us at [email protected] if you need assistance.

The bubble point is the minimum amount of pressure required to push air bubbles through the largest pore of a wet membrane.  The bubble point is inversely proportional to the pore diameter, as the pore diameter decreases the bubble point increases and vice versa.

Retention efficiency of membrane filters can be directly measured by challenging the filters with suspensions of standard microorganism cultures or particles of known size.  Unfortunately, such efficiency testing is necessarily destructive.  However, since retention characteristics are dependent on pore size, it is possible to correlate destructive challenge testing results to non-destructive membrane bubble point tests.  In this manner, the relationship between membrane pore size and membrane bubble point is empirically determined.  Typically, a minimum bubble point can be determined and specified for a particular pore size rating.  The bubble point specification is then used for quality control during membrane manufacture.  The bubble point can also be used by the consumer as a nondestructive test to verify membrane integrity before and/or after use.    

Depth filters are constructed with relatively thick filtration media and typically have nominal pore size ratings >1µm. Due to their large void volume, they capture significant amounts of particulate within their pore structure.
Membrane filters are typically composed of polymers that have been chemically processed, resulting in highly porous thin films with microscopic pore structures. Membrane filters typically have absolute pore size ratings <1µm, with some exceptions. Because of their very fine pore structure, membrane filters tend to trap the majority of particles on the surface. However, smaller particles with diameters near or below the pore size rating can be captured within the membrane or pass through the membrane.

membrane filters vs separator papers

To ensure ease of use, the membrane filters as stacked in their packaging are interleafed with layers of separator paper.  In most cases, the membrane filters will be white in color except for the track-etch membranes which are colorless and translucent.  In some special cases, the membranes will be dyed dark grey to black in appearance.  In all cases, the separator paper will be a different color than the membrane and is usually not white.  Please contact us at [email protected] if you need assistance.