Towards the use of monodisperse ferromagnetic particles in low resource malaria diagnostic devices

Abstract

Given the prevalence of malaria in underdeveloped countries, specialized solutions must be developed for its diagnosis. The most common diagnostic throughout these regions is a lateral flow assay. While generally useful, these have a higher limit of detection than standard malaria diagnostics in the developed world. To help bridge this gap we are developing a system to concentrate malaria biomarkers on a lateral flow strip in order to lower its effective limit of detection. By using functionalized ferromagnetic micro-particles in a patient sample we can concentrate biomarkers and then transfer them to a surface leaving behind the bulk fluid. One of the first steps towards this is to understand parameters affecting particle transfer from an idealized fluid and across an air gap to a surface below. We were able to transfer various bead across distances of over 3mm for samples over 300?g when holding the sample orthogonal to the surface and over 200?g when holding the sample at a 45° angle to the surface. Bubble exchange between the seems to be the limiting factor driving bead transfer and occurs more readily in 45° samples allowing bead transfer to occur in an unimpeded fashion leading to more easily discernable trends within these samples.