Diagnostic components

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Having the expertise and manufacturing capability to customise fibrous products to meet very specific requirements, Whatman has an established reputation for supplying key components for a wide range of applications.

For today's diagnostic device manufacturers, time-to-market is more critical than ever. They seek cost-efficient business partnerships that yield consistent product performance and quality - at increasingly aggressive rates of development. In essence, they require experienced single-source suppliers with extensive product lines that address the full spectrum of diagnostic applications. That is why so many diagnostic companies partner with Whatman.

We offer a comprehensive family of high-quality, solid-phase media - from sample wicks, blood separators and conjugate release pads to absorbent sinks, sample collection/transport materials and dipsticks.

In addition, our in-depth line of nitrocellulose membranes and our proprietary FUSION (single layer matrix) technology provide proven performance for lateral flow assays.

What's more, our pioneering work in emerging applications - including track-etched membrane and molecular diagnostic technologies - helps companies remain on the forefront of breakthrough diagnostic solutions.

By combining the highest quality standardized solutions with unsurpassed technical expertise and support, we enable diagnostic companies to optimize their product offerings quickly and cost-effectively. We thereby accelerate a company's time-to-market and maximize their competitive advantage.

  • Diagnostic membranes
 
Diagnostic membranes
> Immunopore diagnostic membrane
 Immunopore ™ diagnostic membranes
Whatman Immunopore was the first nitrocellulose membrane specifically designed for lateral flow diagnostics in 1995. Since then, the manufacturing process has been continuously refined to increase consistency and expand the range of wicking rates. Whatman Immunopore products include a proprietary polymer in the membrane matrix to ensure rapid rewetting and low background signal-eliminating protein-binding interference commonly experienced with surfactants. 

Features and Benefits
 

  • High sensitivity. 
    Capture line shows high intensity, making low positives easy to read and improving test range.
  • High consistency. 
    Demonstrate outstanding within- and between-batch consistency for lateral wicking rates (see graphs), making test development more predictable.
  • Long shelf life. 
    No significant performance change after three years' storage under ambient conditions, simplifying membrane handling and storage operations.
  • Product versatility. 
    Strong results regardless of capture reagent or analyte type. Can be utilized in virtually all tests.

Product Range and Properties 
Immunopore SP 
Mylar cast membrane construction. Maximum sensitivity coupled with low flow/wicking rate. Ideal for use with low-viscosity samples when maximum capture line intensity is required.

Immunopore FP 
Mylar cast membrane construction. Excellent general membrane offers high capture line intensity coupled with faster flow/wicking rate.

Immunopore RP 
Mylar cast membrane construction. Fastest flowing membrane, yielding shorter test times while still retaining excellent capture line intensity and reproducibility.

Standard Sizes 
Available in 50m rolls of 25mm width, for other sizes please inquire.

Given the increasing demand for whole blood assays, Whatman offers a family of blood separators specifically designed to meet the strict requirements of the rapid diagnostics market.

Features and Benefits

  • Faster development. 
    The four distinct separator grades facilitate faster and simpler development of any whole blood assay.
  • Optimal performance. 
    All separators are optimized to consistently provide required separation rates with high serum yields and no red cell haemolysis.
  • Rapid separation. 
    Blood separation is completed in 30 to 120 seconds.

Product Range and Properties

Since product selection for specific blood separation applications can be complex, please consult the "Where to Start" chart for typical applications.

LF1 
Designed for use in lateral flow assays. Performs well with one or two drops of whole blood.

MF1 
Appropriate for lateral or vertical flow assays. Typically used for whole blood volumes between 30µL and 100µL.

VF1 
Suitable for vertical flow assays. Typically used in a multi-layer format for separating larger volumes of blood.

VF2 
Primarily a vertical separator that can be used in a single- or multi- layer format to separate a wide range of blood volumes.

Standard Sizes 
Reels are available in the following standard sizes:

12mm x 50m 
17mm x 50m

Blood Separation
Lateral Flow   Vertical Flow  
  Single Layer Multiple Layer
<30µL >30µL <100µL >100µL  
LF1 MF1     VF2 VF1  
20 20 Minimum volume of whole blood that can be used (µL)   40 40  
0.59 0.77 Minimum area of separator to separate the minimum volume (cm2)   0.47 0.52  
21.2 17.6 Typical volume of serum recovered from 40µL of whole blood   14.4 16.1  
86 73 Percentage of available serum obtained (%)   60 67  
46 57 Basis weight (g/m2)   125 121  
247 367 Thickness (µm@53kPa)   785 632
 
 
 
Conjugate release
> Conjugate release
Conjugate release materials are critical to lateral flow assays. To ensure strong assay performance, the conjugate must dry without damage or aggregation and release rapidly when the sample is applied. For consistent, reliable results involving conjugate release, diagnostic manufacturers rely on Whatman products. 

Features and Benefits

  • Choice of product. 
    Rapid Release materials are optimized to provide improved performance without blocking, while Standard Release materials allow the development of proprietary blocking protocols.
  • Inherently hydrophilic conjugate pads. 
    Do not require treatment prior to conjugate application, decreasing time required for diagnostic kit production.
  • Innovative design.
    Enables the conjugate to dry as a solid phase without colloidal system deterioration. Open structure allows rapid pad penetration by both conjugate and sample.
  • Product versatility. 
    Can be used as combined sample wick/conjugate release pads when additional wicks are not desired.

Product Range and Properties

Rapid 24/Rapid 27 
No additional blocking step is required, accelerating assay development and simplifying manufacturing. Typically release more conjugate than untreated pads, reducing reagent costs. Pads rewet rapidly and capture line intensity is increased, significantly improving performance. Rapid 24 has higher absorption capacity and greater flexibility, while Rapid 27 has greater tensile strength.

Standard 14/Standard 17 Untreated grades ideal for conjugate pad optimization for particularly sensitive assays. Manufactured to enable optimization giving the same results every time. Pads rewet quickly and naturally without requiring surfactant treatment, facilitating simplified production. Standard 14 has higher absorption capacity and greater flexibility, while Standard 17 has greater tensile strength for easier manufacturing.

Standard Sizes 
Reels are available in the following standard sizes:

12mm x 50m 
17mm x 50m 
22mm x 50m 
27mm x 50m

Typical Test Data - Conjugate Release Materials
Grade Thickness (µm@53kPa) Absorption Capacity (mg/cm2) Max. Pore Size (µm) % Release of Gold Conjugate (after 90 sec)
Rapid 24 340 55 22 89
Rapid 27 365 40 22 86
Standard 14 355 55 23 75
Standard 17 370 35 23 75
 
 
 

Track etched membranes

Track etched membranes
> Track etched membranes
Whatman is actively involved in state-of-the-art R&D initiatives designed to keep our customers at the forefront of diagnostic technology. We provide our vision for the field's most important emerging applications and our assessment of the critical role Whatman products will play as those applications help our partners achieve competitive advantage. 

Track etched membranes (TEMs) are extremely thin yet highly controlled membranes. Traditionally, TEMs have been used for sample filtration before critical applications such as HPLC.

Broad Applicability Across Applications

The properties that make TEMs ideal for applications like filtration are becoming increasingly important for diagnostic tests.

Cell capture. 
Tightly controlled filtration properties allow you to capture cells of a specific pore size on the membrane surface. Enables cells to be detected in a clearer environment, yielding improved accuracy.

Particle capture and latex agglutination. 
The distinct pore size of TEMs enables the capture of particles of known sizes. Now you can construct assays in which capture reagents are bound to a latex bead (i.e., bead capture assays) or the antigen causes particle agglutination whereby the agglutinated clusters are captured on the membrane surface.

Biosensors. 
With biosensors, it is important to control liquid migration rates onto the sensor and prevent potential contaminants from reaching the sensor surface. The flow properties of a TEM can be chosen to yield the correct flow of liquids or gases through the membrane in order to obtain optimal sensitivity. It is also possible to modify surface properties so that membranes will serve as barriers to contaminants.

Erythrocyte deformability testing. 
Since healthy erythrocytes are highly flexible, they will readily change shape to pass through small openings. In several haemopathies, the ability of the cell to flex is reduced to the extent that it can no longer pass through a small aperture. When TEMs are used as a barrier to abnormal erythrocytes, it is possible to test for disease states.

In short, the degree of control that is possible in TEM manufacturing not only gives rise to a number of applications in which standard materials would fail, but also makes process validation and regulatory control easier and more intuitive.

Features and Benefits

  • Defined pore size. 
    The claimed nominal pore size is the largest pore size present in the membrane. The intra-lot variation in pore size is typically between two and three percent.
  • Biologically inert. 
    Since TEMs are manufactured from PC, the possibilities of assay interference are remote.
  • Control of flow rate. 
    TEMs are available with hydrophobic or hydrophilic surfaces in a range of pore sizes and pore densities. The flow rate of liquid through the membrane can therefore be tightly controlled.
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