A Lab-On-chip Tool for Rapid, Quantitative, and Stage-selective Diagnosis of Malaria

Adv Sci (Weinh). 2021 May 13;8(14):2004101. doi: 10.1002/advs.202004101. eCollection 2021 Jul.

Abstract

Malaria remains the most important mosquito-borne infectious disease worldwide, with 229 million new cases and 409.000 deaths in 2019. The infection is caused by a protozoan parasite which attacks red blood cells by feeding on hemoglobin and transforming it into hemozoin. Despite the WHO recommendation of prompt malaria diagnosis, the quality of microscopy-based diagnosis is frequently inadequate while rapid diagnostic tests based on antigens are not quantitative and still affected by non-negligible false negative/positive results. PCR-based methods are highly performant but still not widely used in endemic areas. Here, a diagnostic tool (TMek), based on the paramagnetic properties of hemozoin nanocrystals in infected red blood cells (i-RBCs), is reported on. Exploiting the competition between gravity and magnetic forces, i-RBCs in a whole blood specimen are sorted and electrically detected in a microchip. The amplitude and time evolution of the electrical signal allow for the quantification of i-RBCs (in the range 10-105 i-RBC µL-1) and the distinction of the infection stage. A preliminary validation study on 75 patients with clinical suspect of malaria shows on-field operability, without false negative and a few false positive results. These findings indicate the potential of TMek as a quantitative, stage-selective, rapid test for malaria.

Keywords: diagnostic tests; hemozoin nanocrystals; impedimetric detection; lab‐on‐chip; magnetic sorting; malaria; red blood cells.

Publication types

  • Evaluation Study

MeSH terms

  • Erythrocytes / parasitology
  • Evaluation Studies as Topic
  • Humans
  • Lab-On-A-Chip Devices*
  • Malaria / diagnosis*
  • Reproducibility of Results
  • Sensitivity and Specificity