Abstract

Toward Highly Sensitive Point-of-Care Testing Using Linear Cryogel Arrays

Thomas Brandstetter, Senior Scientist, University Freiburg

The lateral flow assay (LFA) can be considered as the most successful microfluidic platform for point-of-care testing (POCT).(1) However, there are still many applications where the analytical performance of LFAs is insufficient and novel concepts are needed. A radically new approach to perform immunochromatographic assays has recently been introduced.(2) With the aim to overcome intrinsic system limitations of LFAs, the hydrophobic nitrocellulose membrane is replaced by a linear assembly of hydrophilic, porous cryogel monoliths functionalized with different biomolecules and anchored in a transparent capillary. This assembly enables fluid flow by capillary action and simple optical detection. Hence, highly POC compatible assays analogous to a classical LFA can be performed. However, in contrast to the widely used nitrocellulose membrane, the used cryogel materials possess strong protein-repellent properties and are highly transparent. Thus, a strong increase in device sensitivity is achieved. First demonstrator devices were successfully realized using an attractive in-situ cryogelation method,(3) offering high automatization, miniaturization and multiplexing potential. Newest developments of the system toward an application in POCT, which includes a prototype platform for the detection of Lyme disease and novel insights on the realization of passive fluid flow, are presented.