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[1] Adapted from information found at the The National Cancer Institute (NCI) at nano.cancer.gov |
In the fight against cancer, nanotechnology introduces unique approaches to diagnosis and treatment that could not even be imagined with conventional technology. New tools engineered at sizes much smaller than a human cell will enable researchers and clinicians to detect cancer earlier, treat it with much greater precision and fewer side effects, and possibly stop the disease long before it can do any damage. Imagine a nanoparticle that can be used to light up a tumor in an MRI, destroy cancer cells by converting laser light into heat, and allow the physician to visually track the progress of treatment.
The National Cancer Institute (NCI) focuses on applying research and translating it into clinical products in key programmatic areas that are focused by Concurrent Analytical. These include:
For several years, the National Cancer Institute (NCI) has supported exploratory work integrating nanotechnology into cancer research. The NCI is moving the science of nanotechnology into the clinic to change the way we diagnose, treat and prevent cancer. Today, nanodevices are used in detecting cancer at its earliest stages, pinpointing its location within the body, delivering anticancer drugs specifically to malignant cells, and determining if these drugs are killing malignant cells. As research continues and nanodevices are evaluated for safety and efficacy, nanotechnology will result in significant advances in early detection, molecular imaging, assessment and therapeutic efficacy, targeted and multifunctional therapeutics, and the prevention and control of cancer.
Over the next five years, the NCI will fund $144.3 million in research and development through the NCI Alliance for Nanotechnology in Cancer. This Alliance will direct research efforts and facilitate partnerships across the scientific and research communities and the public and private sectors. These efforts capitalize on the multidisciplinary nature of nanotechnology development and will hasten its application to the elimination of suffering and death due to cancer.
What is Nanotechnology?
Nanotechnology is the development and engineering of devices so small that they are measured on a molecular scale. This emerging field involves scientists from many different disciplines, including physicists, chemists, engineers, information technologists, and material scientists, as well as biologists. Nanotechnology is being applied to almost every field imaginable, including electronics, magnetics, optics, information technology, materials development, and biomedicine.
The Size of Things
Nanoscale devices are one hundred to ten thousand times smaller than human cells. They are similar in size to large biological molecules ("biomolecules") such as enzymes and receptors. As an example, hemoglobin, the molecule that carries oxygen in red blood cells, is approximately 5 nanometers in diameter. Nanoscale devices smaller than 50 nanometers can easily enter most cells, while those smaller than 20 nanometers can move out of blood vessels as they circulate through the body.
Because of their small size, nanoscale devices can readily interact with biomolecules on both the surface and inside cells. By gaining access to so many areas of the body, they have the potential to detect disease and deliver treatment in ways unimagined before now.
Nanotechnology in Cancer Diagnosis and Therapy
Biological processes, including events that lead to cancer, occur at the nanoscale. Nanotechnology offers unprecedented access to the interior of living cells, and therefore provides researchers with the opportunity to study and interact with normal and cancer cells in real time, at the molecular and cellular scales, and during the earliest stages of the cancer process.
Nanodevices can provide rapid and sensitive detection of cancer-related molecules by enabling scientists to detect molecular changes even when they occur only in a small percentage of cells. They also have the potential to radically change cancer therapy for the better and to dramatically increase the number of highly effective therapeutic agents. Nanoscale constructs can serve as customizable, targeted drug delivery vehicles capable of ferrying large doses of chemotherapeutic agents or therapeutic genes into malignant cells while sparing healthy cells, greatly reducing or eliminating the side effects that accompany many current cancer therapies.
Diagnostics SERS Surface Enhance Raman Labels are an ultrasensitive technique in detecting tumor markers. SERS is an optical techniques that uses "tags" to link to the target cancer tumor marker. A low cost Raman spectrometer is then used to detect the SERS tag. This method has been used widely with fluorescence tags. However, SERS has five more noteworthy features over that of fluorescence. One, the optimum SERS excitation wavelength is dependent on the chemical/physical properties of the enhancing substrate and not the photophysics of the scatterer, facilitating multi-label readout by requiring only one excitation wavelength. Two, Raman responses are much less susceptible to photobleaching than fluorescence, enabling the use of extended signal averaging to lower detection limits. Three, our design strategy for Raman labels minimizes the distance between the gold nanoparticle surface and label scattering center, which is particularly significant because surface enhancement has been shown to vary inversely with the 10th power of the separation distance. Four, SERS with gold substrates requires long wavelengths (i.e., red to near infrared region) for effective excitation, which reduces background interference from native fluorescence of the sample. And five, breakthroughs in the past decade have greatly simplified hardware, yielding high performance, compact, and portable instrumentation at readily accessible cost structures (e.g., purchase prices in the range of $10K - 15K).
Imaging and Therapeutics
Spherical Gold
Nanoparticles
Nanoparticles can be engineered to target cancer cells for use in the molecular imaging of a malignant lesion. Large numbers of gold nanoparticles are safely injected into the body (unlike Quantum Dots that are toxic) and preferentially bind to the cancer cell, defining the anatomical contour of the lesion and making it visible.
These nanoparticles give us the ability to see cells and molecules that we otherwise cannot detect through conventional imaging. The ability to pick up what happens in the cell - to monitor therapeutic intervention and to see when a cancer cell is mortally wounded or is actually activated - is critical to the successful diagnosis and treatment of the disease.
Nanoparticulate technology can prove to be very useful in cancer therapy allowing for effective and targeted drug delivery by overcoming the many biological, biophysical and biomedical barriers that the body stages against a standard intervention such as the administration of drugs or contrast agents.
Gold Nanorods
Gold Nanorods function much like spherical gold nanoparticles in that they may be engineered to target cancer cells for use in the molecular imaging of a malignant lesion. Large numbers of nanoparticles are safely injected into the body and preferentially bind to the cancer cell, making it visible using different imaging moieties including Two Photon Fluorescence, Optical Coherence Tomography, and Photoacoustic Imaging. The added advantages of gold nanorods is their ability to provide these imaging abilities at near-infrared wavelengths. At these wavelengths, skin and tissue are most transparent, so deep tissue imaging is possible.
Further, gold nanorods possess strong absorption features at these same wavelengths and are very efficient photothermal converters. That is, a simple low power diode laser may be used outside the body to heat the gold nanorods to high enough temperatures that the attached cancer tumor is destroyed.
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