A research team at the University of Pennsylvania has developed a safer, efficient and economical method to coat contrast agents made of nanoparticles comprising iron oxide in order to make them interfere only with the tumor’s acidic environment, paving the way for eliminating the potential health risks and limitations of heavy or radiation metals that are commonly used as contrast agents in cancer imaging technologies.
To improve the image quality of magnetic resonance imaging (MRI), physicians are nowadays using the iron oxide nanoparticles as contrast agents, which are coated with dextran whose outer layer avoids the absorption or bonding of these nanoparticles by the body, thus avoiding potential risks to the patients. This inert coating makes the nanoparticles to be removed safely subsequent to the completion of the imaging. However, this technique also prevents the target-specific treatment of diseased tissues by these nanoparticles. Receptor-based methods also have their own limitations.
The Penn research team used the behavior of tumor metabolism dubbed as the Warburg effect to overcome these limitations. The team took advantage of the pH conditions of the cancer tissues that are lower than that of healthy tissues. It used a sugar-based polymer known as glycol chitosan that interacts with acids as the coating material for the transfer of nanocarriers, which stays neutral when they are close to the healthy tissues but getting ionized in the acidic conditions of the tumors. The charge change that happens in the region of the tumor sites attracts and retains the nanocarriers at these sites.
The acidity of a tumor site varies with the intensity of the malignancy of a tumor. Thus, glycol chitosan coating can effectively detect the intensity of the malignancy of a tumor, paving the way for more treatment options of cancer. According to Andrew Tsourkas, one of the researchers, glycol chitosan finds use in applications other than imaging, as it can be used to coat any kind of nanoparticle. It can be used to supply drugs to the cancer sites, he added.
Due to their capability to precisely identify malignancy sites, glycol-chitosan-coated iron oxide nanoparticles can immediately be used in place of current contrast agents in certain breast cancer MRI scans. The research team believes that the glycol-chitosan-coated nanoparticles are able to enhance the diagnostic screening’s specificity within the next 7-10 years.
Source: http://www.upenn.edu