Portable device for optical quantification of hemozoin in diluted blood samples

Objective: This paper focused a novel and portable device prototype with optical detectors to fast and efficiently detect hemozoin (Hz) in blood, aiming malaria diagnostics. Methods: Taking advantage of the malaria parasite particular features in infected blood, particularly the Hz formation, the main innovation described is a portable device for the optical quantification of parasitic Hz in blood, through optical absorbance spectrophotometry. This device comprises detection chambers for fluidic samples, an optical emission and detection system and a power supply system to provide autonomy. The working principle is based on colorimetric detection, by absorbance, at 6 specific wavelengths. A detection algorithm relates the absorbance values at all wavelengths to quantify the Hz concentration, thus working as a biomarker of malaria presence and stage. Results: Under the tested conditions, e.g., in fluidic samples containing synthetic Hz, hemoglobin and diluted whole blood, the device detected Hz above 1 μg/ml concentrations with 100% sensitivity and 96.3% specificity. Conclusion: This work features an autonomous, portable, 1-minute analysis time and low-cost per test device, without the need for samples centrifugation, allowing the use of whole blood. Significance: The presented device is a step ahead for meeting the growing clinical demands for reliable, rapid, portable and quantitative malaria diagnosis.