Paper-based sensor detects malaria parasites
doi:10.1038/nindia.2019.65 Published online 24 May 2019
Researchers have invented a low-cost, paper-based sensor that can detect minute traces of malaria parasites, including one that causes malignant malaria in humans1. This sensor will be useful for diagnosing malaria infection at an early stage.
Existing kits for detecting malaria parasites yield variable results, making it difficult to accurately diagnose such infections. To overcome this, scientists from the Indian Institute of Technology in Guwahati, India, fabricated the sensor using DNA-attached magnetic beads that bind to the parasite-specific enzymes, a medical syringe and dye-attached, polymer-coated papers.
The enzymes attached to the beads were Plasmodium lactate dehydrogenase (PLDH) and Plasmodium falciparum glutamate dehydrogenase (Pf GDH). The researchers, led by Pranab Goswami, passed a solution containing the beads through a syringe to the paper. This triggered a chemical reaction, bringing about a visible colour change on the paper surface.
Blue changed to pink, signalling the presence of the parasitic enzymes. The intensity of the colour change increased with the increasing concentrations of the enzymes.
The sensor selectively detected the enzymes even in the presence of other proteins that are usually found in human blood.
The colour change on the paper may be used for the quantitative detection of malaria parasites using suitable camera-integrated software. The software converts the colour signals to readable digital signals in a smart phone, indicating the enzymes’ concentrations.
Each test costs less than 10 rupees. The sensor has been found to be stable even in hot and humid climates in malaria-endemic areas, says lead author Naveen Kumar Singh.