Researchers Curate New Chip That Can Mimic Organs, Helping With More Accurate Malaria Tests

Technology, never stops, it would rather make mistakes than find itself in the tong of a halt. Innovations will continue to happen, to make life easier for humans and to open new grounds for discovery

There’s been more information coming to light about the “lab-on-a-chip” technology recently, and for good reason, as these devices can be used to mimic organs, and in a long run may be able to replace animal models in biomedical research, but ultimately, they have the potential to carry out a range of complex tests that were previous restricted to the lab, now contained in a single, low-cost, portable device.

With over 229 million new malaria cases and 409,000 global deaths reported in 2019 alone, malaria has become endemic in the world. Researchers like Riccardo Bertacco of the Politecnico di Milano considers this new tool as effective against debilitating diseases like Malaria.

“I’ve known malaria since my stay in Cameroon 25 years ago as volunteer,” said Bertacco. “I got it at least twice and I directly experienced the tremendous personal, clinical, and societal impact of this infection, which affects 3.5 billion of people worldwide.”

“Lab-on-chips are appealing because they can be integrated on a small chip with biochemical and electronic functionalities, allowing the creation of automated smart devices that don’t require experienced personnel to run them,” said Lorenzo Pietro Coppadoro, a Ph.D. student in the Department of Electronics Bioengineering and Informatics of Politecnico di Milano. “With excellent sensitivity and [the ability] to make results available to clinicians via the internet, [this could] enable a remote healthcare system with sizable reduction of costs and improvement of quality.”

In 2016, Bertacco says a publication describing the magnetic properties of red blood cells infected by malaria parasite piqued his interest, “I thought to myself, ‘If malaria infected red blood cells are magnetic, then that’s [essentially] my job’, and the idea for a novel lab-on-chip diagnostic test based on this concept of magnetism came about,” said Bertacco.

The device was named TMek, after a Cameroonian local language of a small village called Mbalmayo after “Tid Mekii” meaning malaria”.

“TMek is based on a microchip implementing the selective magnetic capture of infected red blood cells and free hemozoin crystals in a whole blood sample,” explained Professor Giorgio Ferrari, one of the study’s authors. “Healthy red blood cells sediment under the action of gravity, while infected, [magnetic] red blood cells are captured on some micro-magnets fabricated on the chip.”

The magnets upon which the infected red blood cells become trapped are built on top of electrodes. As infected cells build up, the impedance measured by the electrodes increases proportionally.

“The microchip is thus capable of capturing infected red blood cells and free pigment in a whole blood smear and quantifying their concentration using an electrical detection in just 5-10 minutes, with a limit of detection of 10 parasites/μl,” added Ferrari.

This is a significant achievement given the current landscape and limitations of rapid tests that are currently available for malaria. “The WHO strongly supports the use of rapid diagnostic tests based on the detection of antigens of Plasmodium in a blood smear,” explained Professor Spinello Antinori, another of the study’s authors. “However, available rapid tests still have a relatively high limit of detection (roughly 200 parasites/μl), an operating time of 15-20 minutes, and are purely qualitative and do not provide any quantification of the level of parasitaemia.”

 they still require almost 60 minutes to run, are not quantitative (which would help clinicians determine disease stage) and are not compatible for widespread use in the field.

“According to our preclinical validation carried out in Cameroon in April 2019,” said Francersca Milesi, a Ph.D. student in the Physics Department at Politecnico di Milano, “TMek represents a step forward, as its limit of detection is one order of magnitude lower of that of currently used rapid tests, while it holds potential to become a quantitative and stage-selective rapid test suitable for all malaria species.”

Reference: Marco Giacometti, et al., A Lab-On-chip Tool for Rapid, Quantitative, and Stage-selective Diagnosis of Malaria, Advanced Science (2021). DOI: 10.1002/advs.202004101