A new microchannel capillary flow assay (MCFA) platform with lyophilized chemiluminescence reagents for a smartphone-based POCT detecting malaria

Microfluidic Platforms: Smartphone-based point-of-care testing for malaria A smartphone-based point-of-care-testing (POCT) analyzer using a microfluidic platform has been developed for detecting infectious diseases, such as malaria. A major challenge to health care has been a lack of simplified, inexpensive POCT analyzers that can quantitatively detect low concentrations of target biomarkers in disease diagnosis. A team headed by Chong H. Ahn at the University of Cincinnati, United States has developed a handheld POCT system for detecting infectious diseases that uses a smartphone for display, data transfer, storage, and analysis. Their system employs a novel microfluidic-based platform, which utilizes the ultra-high sensitivity of chemiluminescent detection: it was sufficiently sensitive to detect active malarial infection. The authors believe their microfluidic platform and smartphone analyzer can be easily customized for different biomarkers, permitting low-cost handheld POCT systems to be applied for various infectious diseases. There has been a considerable development in microfluidic based immunodiagnostics over the past few years which has greatly favored the growth of novel point-of-care-testing (POCT). However, the realization of an inexpensive, low-power POCT needs cheap and disposable microfluidic devices that can perform autonomously with minimum user intervention. This work, for the first time, reports the development of a new microchannel capillary flow assay (MCFA) platform that can perform chemiluminescence based ELISA with lyophilized chemiluminescent reagents. This new MCFA platform exploits the ultra-high sensitivity of chemiluminescent detection while eliminating the shortcomings associated with liquid reagent handling, control of assay sequence and user intervention. The functionally designed microchannels along with adequate hydrophilicity produce a sequential flow of assay reagents and autonomously performs the ultra-high sensitive chemiluminescence based ELISA for the detection of malaria biomarker such as PfHRP2. The MCFA platform with no external flow control and simple chemiluminescence detection can easily communicate with smartphone via USB-OTG port using a custom-designed optical detector. The use of the smartphone for display, data transfer, storage and analysis, as well as the source of power allows the development of a smartphone based POCT analyzer for disease diagnostics. This paper reports a limit of detection (LOD) of 8 ng/mL by the smartphone analyzer which is sensitive enough to detect active malarial infection. The MCFA platform developed with the smartphone analyzer can be easily customized for different biomarkers, so a hand-held POCT for various infectious diseases can be envisaged with full networking capability at low cost.