"The HEMOTECT project aims at the development and implementation of a sensitive sensor for the detection of paramagnetic systems and, in particular, of hemozoin crystals.
Hemozoin crystals (HzC) are the byproduct of malaria infection. The Plasmodium parasite, the agent of malaria, during its intraerythrocytic cycle digests hemoglobin and releases heme which is highly toxic for itself. Detoxification is achieved by the transformation of heme into an iron-containing porphyrin crystal, namely the HzC.The HzC has magnetic and optical properties distinct from any other component of blood.
Malaria transmission has declined by ~40% in the period of 2010-2015 and the possibility of elimination (reduction of transmission to zero in a dened geographical area) in the current decade has been, for the 1rst time in years, considered. Approximately 3.4 billion people are at risk of malaria worldwide, with 627,000 deaths just in 2012, while by the year 2016 there were an estimated 216 million cases of malaria in 91 countries (an increase of 5 million cases over 2015).
Malaria is an entirely preventable and treatable disease, provided the recommended interventions are properly implemented, such as early diagnosis and timely treatment with appropriate anti-malaria medication. Currently, the most reliable and sensitive malaria diagnostic tools are (a) the observation of blood smears using microscopy, and (b) rapid-diagnostic tests (RDTs), which are antigen-based detectors.
These tools are the diagnostic ""gold standards standards"", but they come at a cost. Microscopy is labor intensive and requires trained staff, well equipped laboratories, and cannot be used for high-throughput screening in areas of low-parasitemia levels. RDTs are expected to become more sensitive and cheaper (current cost 75 cents), but they still produce false positives, are susceptible to high-temperature environments, and require 15 minutes to produce a result. It is therefore apparent that at present, there
is a large need for a new diagnostic method that will allow the rapid and denitive diagnosis of infected, asymptomatic, cases that remain undetectable by the currently used field methods.
A new physical tool has recently emerged as a unique magnetic-field sensor for physics and biology and it is based on the exploitation of the spin properties of one particular color center in diamond, known as the Nitrogen-Vacancy (NV) center. The NV center is formed by a substitutional nitrogen atom and a vacancy on adjacent lattice sites of the diamond crystal lattice, and possesses remarkable magneto-optic properties which allow for the highly sensitive detection of magnetic fields (as well as electric fields, pressure, and temperature) at the nanometer scale.
The main goal of the HEMOTECT project is to develop a novel technology that would allow for the label-free detection of HzC with sensitivity limits better than the currently used malaria diagnostic ""gold standards"". The implementation of an sensor using NV centers in diamonds allows for the detection of HzC with higher sensitivities and acquisition times faster than the current diagnostic ""gold standards"", and paves the way towards a novel malaria diagnostic technique. Our scientific breakthrough is the demonstration of the principles towards a versatile and easy-to-use and cost-effective instrumentation that could be used for the early diagnosis of malaria, and therefore, contribute to the eradication of one of the deadliest diseases in the world.
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