A tumor, indicated by the white arrow, is darkened by a glycol chitosan contrast agent.
New research from University of Pennsylvania engineers shows a way to coat an iron-based contrast agent so that it only interacts with the acidic environment of tumors, making it safer, cheaper and more effective than existing alternatives.
The research was conducted by associate professor Andrew Tsourkas and graduate student Samuel H. Crayton of the department of bioengineering in Penn’s School of Engineering and Applied Science. It was published in the journal ACS Nano.
By using glycol chitosan — a sugar-based polymer that reacts to acids — the engineers allowed the nanocarriers to remain neutral when near healthy tissue, but to become ionized in low pH. The change in charge that occurs in the vicinity of acidic tumors causes the nanocarriers to be attracted to and retained at those sites.
This approach has another benefit: the more malignant a tumor is, the more it disrupts surrounding blood vessels and the more acidic its environment becomes. This means that the glycol chitosan-coated is a good detector of malignancy, opening up treatment options above and beyond diagnosis.
“You can take any nanoparticle and put this coating on it, so it’s not limited to imaging by any means,” said Tsourkas. “You could also use it to deliver drugs to tumor sites.”
This by far is the most important part of the new technology. Direct delivery of drugs to a tumor site is the future. We are already seeing this already in some areas, but invasive techniques must be used. This is a non-invasive drug delivery system.