One of the difficult challenges in treating diseases like cancer, atherosclerosis, stroke, arterial occlusion, and others, is that the drugs effective against the diseases are also often toxic to the body’s healthy tissues, causing collateral tissue damage and side effects. One approach to dealing with this challenge is to direct the drugs directly at the tumor, and one way to try to do this is with magnetic nanoparticles, coated with the drug, direct by magnetic fields.
The solution Lunnoo and Puangmali suggest would be to use the 10-200 nanometer particles in blood vessels in parts of the body with low blood velocity, such as smaller blood vessels and micro-capillary vessels.
So Thodsaphon Lunnoo and Theerapong Puangmali at the Materials Science Program at Khon Kaen University in Thailand attempted to model how these coated nanoparticles would fare in a simulated circulatory system. Their results, presented in the article, “Capture Efficiency of Biocompatible Magnetic Nanoparticles Arterial Flow: A Computer Simulation for Magnetic Drug Targeting” published in Nanoscale Research Letters, show several key findings. First, the amount of drug coating on the nanoparticle had no impact on magnetic capture. After that, things get complicated.
They tested particles sizes of various iron and iron oxide compositions (Fe3O4, Fe2O3, and iron alone) from 10 nanometers up to 4 micrometers, and found that the ability to capture and direct those particles with external magnetic fields decreased as the particle size decreased. And that while they could reliably capture and direct particles in the 2-micrometer range, those particles are too big to be absorbed and are eliminated by the reticuloendothelial system. The best size for absorption was 10-200 nanometers, but the magnetic response from these particles was too weak to withstand arterial pressures.
The solution Lunnoo and Puangmali suggest would be to use the 10-200 nanometer particles in blood vessels in parts of the body with low blood velocity, such as smaller blood vessels and micro-capillary vessels. They also suggest using implanted magnets or ferromagnetic microwires that can be located near the diseased tissues with minimally invasive surgery.
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