A two-dimensional paper network format that enables simple multi-step assays for use in low-resource settings in the context of malaria antigen detection

摘要

The lateral flow test has become the standard bioassay format in low-resource settings because it is rapid, easy to use, low in cost, uses reagents stored in dry form, and is equipment-free. However, lateral flow tests are often limited to a single chemical delivery step and not capable of the multi-step processing characteristic of high performance laboratory-based assays. To address this limitation, we are developing a paper network platform that extends the conventional lateral flow test to two dimensions; this allows incorporation of multi-step chemical processing, while still retaining the advantages of conventional lateral flow tests. Here we demonstrate this format for an easy-to-use, signal-amplified sandwich format immunoassay for the malaria protein PfHRP2. The card contains reagents stored in dry form such that the user need only add sample and water. The multiple flows in the device are activated in a single user step of folding the card closed; the configuration of the paper network automatically delivers the appropriate volumes of i) sample plus antibody conjugated to a gold particle label, ii) a rinse buffer, and iii) a signal amplification reagent to the capture region. These results highlight the potential of the paper network platform to enhance access to high-quality diagnostic capabilities in low-resource settings in the developed and developing worlds.