Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA.
Malar J. 2010 Jan 14;9:17. doi: 10.1186/1475-2875-9-17.
Malaria parasites generate free haem upon catabolism of host haemoglobin during their intraerythrocytic growth cycle. In order to minimize oxidative toxicity of the ferric iron, the free haem molecules are polymerized into the biomineral beta-haematin (commonly referred to as haemozoin). Haemozoin crystals are paramagnetic, and this property can be exploited for the purification of late stage parasites as they contain larger haemozoin crystals than early stage parasites and uninfected cells. Commercially available magnets that were originally developed for the purpose of antibody-mediated cell purification are widely used for this purpose. As these methods are not necessarily optimized for parasite purification, the relationship between magnetic field strength and the quantity and quality of yield during parasite purification was explored.
Inexpensive rare-earth neodymium magnets with commercially available disposable columns were employed to explore the relationship between magnetic field strength and recovery of free haemozoin and infected erythrocytes (iRBCs).
Yields of free haemozoin increased nearly linearly with increasing magnetic field strength to the strongest fields tested (8,500 Gauss). Stronger magnetic fields also improved the recovery of iRBCs with no detrimental effects on parasite viability. An in-house constructed magnetic stand, built for $75 in materials, produced superior results when compared with much more expensive commercial products.
Existing protocols for the magnetic purification of free haemozoin and iRBCs result in sub-optimal yields. Inexpensive high-strength neodymium magnets offer a better option, resulting in higher yields with no detrimental effects on parasite viability.
疟原虫在其红细胞内生长周期中分解宿主血红蛋白时会产生游离血红素。为了将三价铁的氧化毒性降到最低，游离血红素分子聚合形成生物矿物质β-血晶素（通常称为疟色素）。疟色素晶体具有顺磁性，这一特性可用于纯化晚期疟原虫，因为它们比早期疟原虫和未感染细胞含有更大的疟色素晶体。最初为抗体介导的细胞纯化而开发的商用磁铁广泛用于此目的。由于这些方法不一定针对寄生虫的纯化进行优化，因此研究了磁场强度与寄生虫纯化过程中游离疟色素和感染红细胞（iRBC）的产量之间的关系。
使用廉价的商用一次性柱稀土钕磁铁来探索磁场强度与游离疟色素和感染红细胞（iRBC）回收之间的关系。
游离疟色素的产量几乎呈线性增加，与所测试的最强磁场（8500 高斯）成正比。更强的磁场还改善了 iRBC 的回收，而对寄生虫的活力没有不利影响。一个内部构建的磁性支架，用 75 美元的材料制成，与更昂贵的商用产品相比，效果更好。
现有的游离疟色素和 iRBC 磁性纯化方案导致产量不理想。廉价的高强度钕磁铁提供了更好的选择，可提高产量，而对寄生虫的活力没有不利影响。
