Capillary Agglutination Technology

Breward, Chris and Richardson, Giles (2006) Capillary Agglutination Technology. European Study Group with Industry > 53rd ESGI [Manchester 21/3/2005 - 24/3/2005].

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Abstract/Summary

In medical diagnostic tests, including pregnancy testing and tests for typed red blood cells, a small fluid sample is placed at one end of a capillary channel, which has been lined with a dried reagent. If the sample contains the analyte (the substance being tested for) then an agglutination reaction occurs between it and the reagent in the channel, and the agglutinated complexes progressively slow the flow and may even block the channel, partially or completely, so that the flow only reaches the far end very slowly, or not at all. The aim is that this should give a reliable detection of quite low concentrations of analyte in the sample. Platform Diagnostics asked the Study Group to construct a mathematical model of the process, so that, for known binding forces in the agglutination complexes, we can design the channel size and shape, and the fluid viscosity, to maximize the reliable detection of low concentrations. A key question is how the flow time depends on channel size, fluid surface tension and viscosity, (a) in the absence of agglutination, and (b) in the presence of agglutination.

Item Type:	Study Group Report
Study Group:	European Study Group with Industry > 53rd ESGI [Manchester 21/3/2005 - 24/3/2005]
Company Name:	Platform Diagnostics Limited
Industrial Sector:	Medical and pharmaceutical
Additional Contributors:	Bond, Philip and Booth, Richard and Clarke, Richard and Cummings, Linda and Dellar, Paul and Duchemin, Laurent and Dyson, Rosemary and Evatt, Geoff and Gelder, David and Griffiths, Ian and Heil, Matthias and Juel, Anne and King, John and Lacey, Andrew and Naire, Shailesh and Nakane, Kazuaki and Ockendon, John and Please, Colin and White, Gordon and Zammett, Rachel
ID Code:	70
Deposited By:	Gordon White
Deposited On:	19 June 2006

Problem Statement

In medical diagnostic tests, including pregnancy testing and tests for typed red blood cells, a small fluid sample is placed at one end of a capillary channel, which has been lined with a dried reagent. If the sample contains the analyte (the substance being tested for) then an agglutination reaction occurs between it and the reagent in the channel, and the agglutinated complexes progressively slow the flow and may even block the channel, partially or completely, so that the flow only reaches the far end very slowly, or not at all. The aim is that this should give a reliable detection of quite low concentrations of analyte in the sample. Platform Diagnostics would like a mathematical model of the process, so that, for known binding forces in the agglutination complexes, the channel size and shape, and the fluid viscosity, can be designed to maximize the reliable detection of low concentrations. A key question is how the flow time depends on channel size, fluid surface tension and viscosity, (a) in the absence of agglutination, and (b) in the presence of agglutination.

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