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2017-06-08 - Colloque/Présentation - communication orale - Anglais - 1 page(s)

Gossuin Yves , Okusa P.N., Vuong Quoc Lam , Duez Pierre , "Effect of the synthetic malaria pigment b-hematin on water NMR relaxation times: implications for malaria diagnosis by NMR" in 10th Conference on Fast Field-Cycling NMR Relaxometry, Mikołajki, Pologne, 2017

  • Codes CREF : Résonance magnétique nucléaire (biophysique) (DI131B), Physique du spin (genre RMN) (DI1234), Biophysique (DI3113)
  • Unités de recherche UMONS : Physique biomédicale (M104)
  • Instituts UMONS : Institut des Sciences et Technologies de la Santé (Santé)
  • Centres UMONS : Physique des matériaux (CRPM)

Abstract(s) :

(Anglais) 200 million patients suffer from malaria, a parasitic disease caused by protozoans of the genus Plasmodium1. Reliable diagnosis is crucial since it allows the early detection of the disease. The development of rapid, sensitive and low-cost diagnosis tools is an important research area. Different studies focused on the detection of hemozoin, a major by-product of hemoglobin detoxification by the parasite. Hemozoin and its synthetic analog, beta-hematin, form paramagnetic crystals. A new detection method of malaria2 takes advantage of the paramagnetism of hemozoin through the effect that such magnetic crystals have on Nuclear Magnetic Resonance (NMR) relaxation of water protons. Indeed, magnetic microparticles cause a shortening of the relaxation times. In this work3, the magnetic properties of two types of beta-hematin are assessed at different temperatures and magnetic fields. Contrary to the conclusions of a recent study4 reporting superparamagnetism, the pure paramagnetism of beta-hematin is confirmed. The NMR relaxation of beta-hematin suspensions is also studied at different magnetic fields and for different echo-times. Our results help to identify the best conditions for beta-hematin detection by NMR: T2 must be selected, at large magnetic fields and for long echo-times. However, the effect of beta-hematin on relaxation does not seem large enough to achieve accurate detection of malaria without any preliminary sample preparation, as microcentrifugation.