Low-resource diagnostic assay based on disruption of radial flow in an evaporating drop

Abstract

More than 700,000 deaths are attributed to malarial infection annually in the rural areas of Sub-Saharan Africa. Effective and reliable early detection is inadequate with currently available technology. Development of a low-cost, sensitive and simple-to-use diagnostic assay appropriate for the point-of-care setting is a critical component of malaria containment efforts. This work has demonstrated a diagnostic assay based on the same mechanism that causes a ring to form in an evaporating coffee drop. This novel method for noninstrumented signal visualization is potentially well-suited for low-resource applications that require a simple-to-use, low cost method for pathogen detection. After exploring and optimizing basic design parameters, we demonstrated proof-of-principle for malaria testing by detecting poly-l-histidine, a biomolecular mimic of pfHRP2. The proposed assay was found to have a limit of detection in the mid-nanomolar range, approximately one order of magnitude higher than the clinically relevant range.