Multimodal nanocomplexes will help to find and destroy cancer
For the treatment of a number of malignant tumors, including breast cancer, it seems extremely promising to use nanoparticles with targeted delivery and the possibility of releasing drugs under the influence of electromagnetic fields. However, for the clinical application of such treatment methods, it is necessary to monitor the distribution and behavior of nanoparticles in a living organism.
Rice University scientists led by Naomi Halas in collaboration with Amit Joshi and his colleagues from Baylor College of Medicine used two different methods to track the delivery of therapeutic nanoparticles to breast tumors. The results of the study, published in the journal Nano Letters (Tracking of Multimodal Therapeutic Nanocomplexes Targeting Breast Cancer in Vivo), not only demonstrate the possibility of creating multimodal nanoparticles and visualizing them in the body, but also provide important information about how targeted delivery agents affect the fate of complex nanoparticles.
The experiments were conducted using gold nanowells, to which scientists added magnetic iron oxide nanoparticles embedded in a thin layer of silicon dioxide, followed by a layer of fluorescent molecules known as ICG, and a layer of targeted antibodies. The entire structure was covered with a layer of biocompatible substance – polyethylene glycol, and antibodies affinity to the HER2 receptor located on the cell membranes of some forms of breast cancer.
To track such nanocomplexes in the organisms of mice with human breast tumors with overexpression of the HER2 protein, scientists used two methods within 72 hours after their introduction: magnetic resonance imaging (MRI) and near-infrared fluorescence imaging (near-infrared imaging, NIR-fluorescence). This approach provides detailed information about the in vivo behavior of diagnostic and therapeutic nanoparticles.
The number of nanoparticles in the tumor reached the highest level 4 hours after injection. In contrast, in tumors that are not characterized by overexpression of the HER2 surface protein, a large accumulation of nanoparticles was not observed. The results obtained by magnetic resonance imaging differed in that the peaks of accumulation of nanoparticles in tumors were observed only 24 hours after administration.
Scientists suggest that these differences are explained by the fact that fluorescent imaging detects nanoparticles bound to the tumor surface, and magnetic resonance imaging detects particles distributed throughout the tumor mass. Of course, it takes longer for nanoparticles to penetrate into the tumor nucleus than for binding to cells on its surface. Throughout the experiment, the nanoparticles remained unbroken, and the same particles carrying the therapeutic agent could release their contents at the most appropriate time and precisely on target.
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of PhysOrg: Tracking therapeutic nanoparticles that target breast tumors
22.12.2010