Volume 95 Issue 3 | p. 6 | Concentrates
Issue Date: January 16, 2017

Nanoparticles deprive tumors of their oxygen

Magnesium silicide particles can react with oxygen in acidic tumor environments
Department: Science & Technology
News Channels: Materials SCENE, Nano SCENE, Biological SCENE
Keywords: nanomedicines, cancer therapies, deoxygenation, magnesium silicide

To suffocate and slow the growth of cancer cells, researchers have designed magnesium silicide nanoparticles that deoxygenate acidic environments, such as those inside tumors (Nat. Nanotechnol. 2017, DOI: 10.1038/nnano.2016.280). The team, led by Wenbo Bu and Jianlin Shi of the Chinese Academy of Sciences’ State Key Laboratory of High Performance Ceramics & Superfine Microstructure, wanted to develop agents that could selectively remove oxygen in tumors but not in healthy tissue, and do so without the use of toxic materials. The agents they developed, 100-nm-diameter Mg2Si particles modified with poly(vinylpyrrolidone), scavenge for oxygen by first breaking down to magnesium ions and silane in acidic environments. The silane then reacts with oxygen to produce water and silicon dioxide. In sealed dialysis bags, the particles react with both dissolved oxygen and oxygen held in hemoglobin. The researchers tested the nanomaterials in mice that had two tumors grafted into their bodies. The scientists injected Mg2Si particles into one tumor and just saline into the other. After eight hours, blood oxygen saturation levels in the particle-treated tumors were about 75% lower than those injected with saline. Meanwhile, oxygen levels didn’t change significantly in normal tissue injected with the particles. But when the team delivered the particles intravenously, instead of directly into tumors, they observed only a slight reduction in tumor oxygen levels. Shi thinks this is because the particles haven’t been optimized to target tumors.

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Polymer-modified Mg2Si nanoparticles break down to SiH4 in acidic environments. The SiH4 then reacts with O2 to produce clumps of SiO2.
Credit: Adapted from Nat. Nanotechnol.
A diagram depicting how Mg2Si deoxygenate tumors.
 
Polymer-modified Mg2Si nanoparticles break down to SiH4 in acidic environments. The SiH4 then reacts with O2 to produce clumps of SiO2.
Credit: Adapted from Nat. Nanotechnol.
 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

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