Quantifying optical properties of hemozoin for the rapid detection of malaria

Hemozoin, a byproduct of plasmodium, is the basis of a new approach for efficient, cost-effective malaria detection. Clinical success of malaria detection with a magneto-optical device (MOD) motivates quantification of the optical interactions forming the basis for this detection mechanism. MOD is used to measure the intensity of polarized light transmitted through a sample of hemozoin suspended in phosphate-buffered saline, subject to a magnetic field ($\vec{B}$) that can be turned on and off. According to Beer’s law, ratios of transmitted light with $\vec{B}$ on and off as a function of hemozoin concentration are related to change in cross-sectional absorption $\Delta\sigma=\sigma_{B\ \textrm{on}}-\sigma_{B\ \textrm{off}}$. We tested several hemozoin concentrations, linearly fit intensity ratio versus concentration data, and accounted for thermal effects using a basis transformation to find $\sigma_{\parallel}-\sigma_{\perp}=1.56\pm0.43 \textrm{cm}^3$ where $\sigma_{\parallel}$ $(\sigma_{\perp})$ corresponds to polarization parallel (perpendicular) to $\vec{B}$. This result is comparable to other published work, and the quantification of $\sigma_{\parallel}-\sigma_{\perp}$ informs our understanding of the magneto-optical properties of hemozoin, which advances malaria detection.