PHILADELPHIA Many imaging technologies and their contrast agents chemicals used during scans to help detect tumors and other problems involve exposure to radiation or heavy metals, which present potential health risks to patients and limit the ways they can be applied. In an effort to mitigate these drawbacks, 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.
Magnetic resonance imaging, or MRI, is an increasingly common feature of medical care. Using a strong magnetic field to detect and influence the alignment of water molecules in the body, MRI can quickly produce pictures of wide range of bodily tissues, though the clarity of these pictures is sometimes insufficient for diagnoses. To improve the differentiation or contrast between tumors and healthy tissue, doctors can apply a contrast agent, such as nanoparticles containing iron oxide. The iron oxide can improve MRI images due to their ability to distort the magnetic field of the scanner; areas they are concentrated in stand out more clearly.
These nanoparticles, which have recently been approved in the United States for clinical use as contrast agents, are literally sugar-coated; an outer layer of dextran keeps the particles from binding or being absorbed by the body and potentially sickening the patient. This non-reactive coating allows the iron oxide to be flushed out after the imaging is complete, but it also means that the particles can't be targeted to a particular kind of tissue.
If the contrast agent could be engineered so it on
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University of Pennsylvania