Nanotechnology in Oncology – A Clinician’s Perspective

This presentation will summarize the general applications of metallic nanoparticles in oncology. To illustrate the potential utility of such nanoparticles in imaging and therapy, two specific examples will be highlighted. The first segment of this presentation will focus on the use of semiconductor quantum dots (QDs) for non-invasive repetitive quantitative optical imaging of cell surface receptors in animal models. This segment will dwell upon the development, characterization, validation and optimization of conjugated quantum dot nanoprobes that permit excellent spatio-temporal image resolution of tumors and other key design considerations. The second segment of this presentation will focus on the use of gold nanoparticles for therapy of cancers. This segment will highlight the potential for gold nanoparticles to augment the efficacy of radiation therapy by physical dose enhancement or via generation of mild temperature hyperthermia, a known mechanism of radiation sensitization. Physical dose enhancement is achieved via an increase in photoelectric absorption due to the high atomic number (Z) of gold that accumulates preferentially within the tumor due to passive extravasation of nanoparticles through leaky tumor vasculature (the enhanced permeability and retention effect. Generation of hyperthermia relies on the ability of colloidal gold to absorb and scatter light strongly at a characteristic wavelength (its plasmon resonance), the large absorption cross section of gold nanoparticles that converts light to heat, and their high thermal conductivity that couples this heat to the surrounding tissue. Furthermore, by varying the geometry and composition of the nanoparticle, its plasmon resonance can be tuned to be within the near infrared region of the electromagnetic spectrum so as to increase tissue penetration of the non-invasive excitation beam to greater tumor depths. Lastly, newer classes of theranostic nanoparticles allow simultaneous diagnosis and therapy of cancer, paving the way for future clinical integration. As illustrated by these examples, there are multiple avenues for overlap between research interests in nanotechnology and clinical oncology; these warrant continued investigation by interdisciplinary teams of clinicians, engineers, chemists, physicists, and biologists in industry and academia.