Discovery

Malaria is a vector-borne infectious disease caused by protozoan parasites. It is one of the most common infectious diseases and an enormous public health problem.

No vaccine is currently available for malaria; but now, a research team led by Dr. Paul Wiseman of the Departments of Physics and Chemistry at McGill University has developed a radically new technique.

Current detection techniques require a laborious process dependent on the skill and availability of trained analysts : stain slides, look for the parasite’s DNA signature under the microscope, and then manually count all the visible infected cells.

On the contrary, the new technique uses lasers and non-linear optical effects to detect malaria infection in human blood. It relies on a known optical effect called third harmonic generation (THG), which causes hemozoin — a crystalline substance secreted by the parasite — to glow blue when irradiated by an infrared laser.

Dr. Paul Wiseman, the leader of research team of the Departments of Physics and Chemistry at McGill University said, we have a fundamental sound frequency and then multiples of that frequency. Non-linear optical effects are similar: if you shine an intense laser beam of a specific frequency on certain types of materials, you generate multiples of the frequency. Hemozoin has a huge, non-linear optical response for the third harmonic, which causes the blue glow.

The researchers say the new technique holds the promise of simpler, faster and far less labor-intensive detection of the malaria parasite in blood samples. They hope to adapt well-established existing technologies like fibre-optic communications lasers and fluorescent cell sorters to quickly move the technique out of the laboratory and into the field.

Adapted from materials provided by McGill University.

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