The small sensor (right in the picture) is supposed to monitor tumors. Image: Donna Coveney / MIT
Reading aloud With a small sensor implant, physicians can follow the progression of cancer treatment: The sensor is left behind in the tissue after a biopsy and it is recorded how strongly the tumor forms certain metabolic products. This will allow researchers led by Michael Cima of the Massachusetts Institute of Technology, Cambridge, to determine whether chemotherapy is effective, whether the cancer drugs even reach the tumor, and whether, for example, after surgery, the cancer is completely removed. The researchers have now tested a sensor prototype of around five millimeters in the tumor of a mouse for the first time. The sensor element consists of a roughly pea-sized, cylindrical plastic housing containing magnetic nanoparticles of the element iron. These particles are coated with a receptor that binds specific molecules from human tissue. These molecules, for example signal substances of a tumor, can penetrate the plastic membrane of the sensor. However, the nanoparticles are too big and remain in the housing. If a substance now binds to the nanoparticles, then the otherwise finely distributed iron particles agglomerate into larger structures. The researchers can detect these lumps with the magnetic resonance spectroscopy.

In the first experiments, the doctors around Michael Cima transplanted a human tumor into a mouse? and the sensor with it. With magnetic resonance spectroscopy, researchers were able to track how a particular tumor's hormone adhered to the nanoparticles. So far, the scientists have monitored with this hormonal tumor marker only a single metabolite of a carcinoma. In principle, physicians could use the method to detect other substances in the tumor environment, the researchers report. Thus, the development of a tumor and the reaction to a cancer drug can be observed almost every minute.

Communication from the MIT ddp / - Martin Schäfer


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