Published On: Wed, Feb 11th, 2015

Nanomedicine: Can cancer tumor control the release of therapeutics?

Silicon carriers for local delivery of anticancer drugs degrade differently when reaching the diseased environment, affecting clinical outcome. A joint study conducted at Technion, MIT and Harvard sheds light on this degradation process, paving the way for improving tumor treatments of this kind  

Prof. Segal Technion


The prestigious journal Nature Communications reveals that silicon nanomaterials for localized delivery chemotherapeutics behaves differently in cancerous tumors in comparison to healthy tissues. The joint study was conducted at the Technion, Massachusetts Institute of Technology (MIT) and the Harvard Medical School. Professor Ester Segal, who heads the Technion group that led the study, explains, “We have shown for the first time that biomaterials in general, and nanostructured porous silicon in particular, behave differently when they are injected (or implanted) at the tumor microenvironment. Over the last few years we successfully engineered silicon to be used as a carrier of anticancer drugs that releases its contents in a controlled manner, and now we have focused on the degradation mechanism of the silicon at the diseased tissue.”


Nanostructured Porous Silicon is the common name for a family of silicon-based materials containing nano-scale holes. This material is known today as a promising drug delivery vehicle, mainly due to its unique characteristics: a large surface area (geared for drug unloading), biocompatbility, and bio-degradability in a safe and non-toxic manner. In recent years, Prof. Segal and her doctoral student Adi Tzur-Balter developed ‘containers’ (carriers) for the delivery of anticancer drugs. Through careful design of the silicon containers, in terms of their pore diameter and surface chemistry, the group achieved optimal features for effective drug delivery.


The important findings of the study, which investigated the behavior of the silicon ‘containers’ in breast cancer tumors, is associated with the accelarated degradation of the silicon material in the diseased area. The resaerch showed that reactive oxygen scecies upregulated in the cancerous environment (in vivo), induce oxidation of the silicon, causing a rapid degradation of the ‘containers’ as compared with (in vitro) lab experiments. As a result, this article sheds light on the process of nanostructured silicon degradation at the tumor microenvironment, and allows for early and smart design intervention of the silicon structure to facilitate controlled release of the drug atthe targeted site. Importantly, the ability to determine and predict material fate in vivo under specific environments is the next step in biomaterial design that would lead to faster and successful clinical translation.



  The image illustrates porous silicon (PSi) particles used as a platform for the delivery of anticancer drugs (highlighted in green on the diagram) and its release at the targeted breast cancer tumors. The degradation of the PSi at the tumor microenvironment was investigated using novel imaging methods. The researchers tracked the decomposition of the material on the diseased tissue and uncovered its degradation mechanism,   which triggers the release of the drugs trapped within the porous medium.




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