Development of a signal measurement technique for application in multi‐analyte liposome immunomigration assays

The potential for development of a multi‐analyte liposome immunomigration solid‐phase competition (LIM‐SPC) assay based on multivariate calibration of spectral reflectance measurements was investigated. A simulation of a multi‐analyte LIM‐SPC assay was carried out using a mixture of three analyte‐tagged liposome preparations, each containing a different colored dye. The liposome preparations were combined according to a statistical experiment design and allowed to migrate up nitrocellulose test strips to a binding zone. After the liposomes were captured at this zone, the reflectance spectrum of the zone was measured. Partial least squares regression was used to develop multivariate calibrations. For the liposome‐encapsulated dyes, the coefficients of determination obtained for car‐boxyfluorescein, sulforhodamine B and isosulfan blue were 0.902, 0.990 and 0.977, respectively. It was concluded that the approach used was suitable for a multi‐analyte LIM‐SPC.