This work reports a high throughput and label-free microfluidic cell deformability sensor for quantitative parasitemia measurement and stage determination for Plasmodium falciparum-infected red blood cells (Pf-iRBCs). The sensor relies on differentiating the RBC deformability (a mechanical biomarker) that is highly correlated with the infection status. The cell deformability is measured by evaluating the transit time when each individual RBC squeezes through a microscale constriction (cross-section ~5 µm×5 µm). More than 30,000 RBCs can be analyzed for parasitemia quantification in under 1 min with a throughput ~500 cells/s. Moreover, the device can also differentiate various malaria stages (ring, trophozoite, and schizont stage) due to their varied deformability. Using Pf-iRBCs at 0.1% parasitemia as a testing sample, the microfluidic deformability sensor achieved an excellent sensitivity (94.29%), specificity (86.67%) and accuracy (92.00%) in a blind test, comparable to the gold standard of the blood smear microscopy. As a supplement technology to the microscopy and flow cytometry, the microfluidic deformability sensor would possibly allow for label-free, rapid and cost-effective parasitemia quantification and stage determination for malaria in remote regions.
Xiaonan Yang a, b, Zhuofa Chen a, Jun Miao c, Liwei Cui c, Weihua Guan a, d
a Department of Electrical Engineering, Pennsylvania State University, University Park 16802, USA
b School of Information Engineering, Zhengzhou University, Zhengzhou 450000, China
c Department of Entomology, Pennsylvania State University, University Park 16802, USA
d Department of Biomedical Engineering, Pennsylvania State University, University Park 16802, USA
Received 17 April 2017, Revised 4 July 2017, Accepted 8 July 2017, Available online 8 July 2017.