Optofluidic single-cell absorption flow analyzer for point-of-care diagnosis of malaria

In this work, an optofluidic flow analyzer, which can be used to perform malaria diagnosis at the point-of-care is demonstrated. The presented technique is based on quantitative optical absorption measurements carried out on a single cell level for a given population of Human Red Blood Cells (RBCs). By measuring the optical absorption of each RBC, the decrease in the Hemoglobin (Hb) concentration in the cytoplasm of the cell due to the invasion of malarial parasite is detected. Cells are assessed on a single cell basis, as they pass through a microfluidic channel. The proposed technique has been implemented with inexpensive off-the-shelf components like laser diode, photo-detector and a micro-controller. The ability of the optofluidic flow analyzer to asses about 308,049 cells within 3 minutes has been demonstrated. The presented technique is capable of detecting very low parasitemia levels with high sensitivity.