A purview into highly sensitive magnetic SERS detection of hemozoin biomarker for rapid malaria diagnosis

Abstract

Here, we report detection of hemozoin, a metabolic byproduct of malaria parasite exhibiting paramagnetic properties using magnetic surface enhanced Raman spectroscopy (M-SERS). The SERS active silver nanorods were deposited over neodymium magnetic substrates (0.3 T) kept at 120 K temperature using glancing angle deposition technique. Magnetic field augmented SERS measurements were performed for hemozoin on these M-SERS substrates and AgNRs deposited over glass (conventional SERS) substrates in presence of an external magnetic field (0.3 T). The SERS signal intensity was found to be enhanced by ten-fold compared to the measurements performed on the conventional SERS substrates in the absence of any magnetic field. The presence of high spin trivalent iron in hemozoin structure led the magnetic field induced agglomeration of these molecules in vicinity of the electromagnetic ‘hotspots’ available on the SERS substrates which was confirmed by running RCWA based simulations. These interactions lead to higher enhancement of vibrational modes of the porphine group directly linked to iron. The limit of detection of hemozoin for M-SERS was obtained as low as 10−11 M (< 10 parasites/µl) which can be employed for early stage malaria detection.