Near infra-red-activatable nanocarriers for selective cancer diagnosis and treatment

Standard treatment strategies for cancer patients include surgery, radiation therapy, and chemotherapy. Although these strategies have been proven effective, they also have associated limitations. An attractive and innovative approach that can be used alone or in combination with the above modalities is based on the systemic or topical administration of a nanomaterial-based photoactive compound. Interaction with light in the near infrared (NIR) region results in either emission of fluorescence, which can be used for photodetection, or absorption of light which results in phototherapy. Nanomaterials have the advantage of providing multi-functional and unique properties in a single device that cannot be readily acquired with conventional small molecular weight compounds. ^ In this study, three different novel nanocarrier systems were designed and evaluated in mediating photodetection and phototherapy in the NIR. The first compound synthesized was a dual-labeled magnetic resonance/optical imaging agent for sentinel lymph node mapping and biopsy. This dual-labeled agent combines the high resolution of magnetic resonance imaging with the highly sensitive detection of optical imaging. The second imaging agent was an activatable optical imaging agent used to monitor cathepsin B activity in vivo and to probe the degradation of poly(L-glutamic acid). This polymeric nanocarrier offers highly sensitive technique for the detection of enzymatic activity, with is not yet possible with small molecular weight compounds. The third agent was a C225-conjugated hollow nanoshell that is targeted to epidermal growth factor receptors. This targeting agent has been demonstrated to mediate photothermal therapy both in vitro and in vivo. ^ These nanocarrier systems are an invaluable tool for the detection of cancer and many other diseases. With improved targeted delivery of these agents, the ability to diagnose diseases will become more sensitive and more specific. Finally, when designed properly, these agents would allow concurrent diagnosis and treatment of patients of various diseases. ^