FUSION 5: A New Platform For Lateral Flow Immunoassay Tests

Appendix: Steps in Using FUSION 5 for a Whole Blood hCG Test

• 1. Start with a reel of FUSION 5 that is 6 cm wide and 50 m long.

• 2. Test line: At the capture zone (approximately 2.5 cm from the edge of the material), apply 2-micron latex beads conjugated to a monoclonal anti-alpha hCG antibody to the FUSION 5 matrix with 10 mM phosphate at pH 7.2.

• 3. Control line: At the control zone (approximately 2.7 cm from the edge of the material), apply 2-micron latex beads conjugated to a goat anti-Mouse IgG antibody to the FUSION 5 matrix with 10 mM phosphate at pH 7.2.

• 4. Conjugate release: At the conjugate release zone (approximately 1 cm from the edge of the material), apply a 150 nm blue-dyed latex colloid conjugated to a monoclonal anti-beta hCG antibody to the FUSION 5 matrix with 10 mM phosphate at pH 7.2 + 0.5% Tween 20 + 0.5% PVA + 0.2% BSA.

After application of the lines (that may be done simultaneously), dry the striped FUSION 5 material for at least 3 hours at 37°C.

Cut the FUSION 5 into 5 mm-wide strips, and place the materials in a plastic housing. Apply 100 µl of whole blood to the test strip. As the whole blood sample wicks up the strip, the cellular component of the blood will be captured by the FUSION 5, allowing the cellular component to flow without the red cells. The acellular component will reach the conjugate release zone and resuspend the blue latex conjugate. Any hCG present will interact with the anti-beta hCG antibodies present on the conjugate. The sample and resuspended conjugate will continue to flow to the capture line, where any hCG present will attach to the anti-alpha hCG antibody present on the capture line, forming a sandwich resulting in the dyed latex being retained at the capture line. A positive result (indicated by the appearance of a blue line at the capture line) will indicate the presence of elevated levels of hCG (a hormone associated with pregnancy in humans). At the control line, the anti-mouse IgG will interact with the monoclonal antibody on the conjugate. The control line will turn blue whether there are elevated levels of hCG present or not.

Note: To provide additional mechanical strength, laminate the FUSION 5 matrix to a vinyl backing card coated with a pressure adhesive. These would be the same cards as those used for the assembly of traditional lateral flow strips.