[Lab on a chip] Pre-concentration by liquid intake by paper (P-CLIP): a new technique for large volu
Microfluidic platforms are an attractive option for incorporating complex fluid handling into low-cost and rapid diagnostic tests. A persistent challenge for microfluidics, however, is the mismatch in the “world-to-chip” interface – it is challenging to detect analytes present at low concentrations in systems that can only handle small volumes of sample. Here we describe a new technique termed pre-concentration by liquid intake by paper (P-CLIP) that addresses this mismatch, allowing digital microfluidics to interface with volumes on the order of hundreds of microliters. In P-CLIP, a virtual microchannel is generated to pass a large volume through the device; analytes captured on magnetic particles can be isolated and then resuspended into smaller volumes for further processing and analysis. We characterize this method and demonstrate its utility with an immunoassay for Plasmodium falciparum lactate dehydrogenase, a malaria biomarker, and propose that the P-CLIP strategy may be useful for a wide range of applications that are currently limited by low-abundance analytes.
Darius G. Rackus,ab Richard P. S. de Campos,ab Calvin Chan,a Maria M. Karcz,ab Brendon Seale,a Tanya Narahari,ab Christopher Dixon,a M. Dean Chamberlainab and Aaron R. Wheeler*abc Author affiliations * Corresponding authors a Department of Chemistry, University of Toronto, 80 St George St., Toronto, Canada E-mail: email@example.com Fax: +416 946 3865 Tel: +416 946 3864 b Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, Canada c Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, Canada