Benefits for Diagnosis
Current imaging methods can only readily detect cancers once they have made a visible change to a tissue, by which time thousands of cells will have proliferated and perhaps metastasized. And even when visible, the nature of the tumor—malignant or benign—and the characteristics that might make it responsive to a particular treatment must be assessed through biopsies. Imagine instead if cancerous or even pre-cancerous cells could somehow be tagged for detection by conventional scanning devices. Two things would be necessary—something that specifically identifies a cancerous cell and something that enables it to be seen—and both can be achieved through nanotechnology. For example, antibodies that identify specific receptors found to be overexpressed in cancerous cells can be coated on to nanoparticles such as metal oxides which produce a high contrast signal on Magnetic Resonance Images (MRI) or Computed Tomography (CT) scans. Once inside the body, the antibodies on these nanoparticles will bind selectively to cancerous cells, effectively lighting them up for the scanner. Similarly, gold particles could be used to enhance light scattering for endoscopic techniques like colonoscopies. Nanotechnology will enable the visualization of molecular markers that identify specific stages and types of cancers, allowing doctors to see cells and molecules undetectable through conventional imaging.
Screening for biomarkers in tissues and fluids for diagnosis will also be enhanced and potentially revolutionized by nanotechnology. Individual cancers differ from each other and from normal cells by changes in the expression and distribution of tens to hundreds of molecules. As therapeutics advance, it may require the simultaneous detection of several biomarkers to identify a cancer for treatment selection. Nanoparticles such as quantum dots, which emit light of different colors depending on their size, could enable the simultaneous detection of multiple markers. The photoluminescence signals from antibody-coated quantum dots could be used to screen for certain types of cancer. Different colored quantum dots would be attached to antibodies for cancer biomarkers to allow oncologists to discriminate cancerous and healthy cells by the spectrum of light they see.