Our comprehensive introduction to nanotechnology and nanoscience
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Nanotechnology in Medicine (Nanomedicine)
For centuries, man has searched for miracle cures to end suffering caused by disease and injury. Many researchers believe nanotechnology applications in medicine may be mankindís first 'giant step' toward this goal. According to Robert A. Freitas, nanomedicine is "...1) the comprehensive monitoring, control, construction, repair, defense, and improvement of all human biological systems, working from the molecular level, using engineered nanodevices and nanostructures;
2) the science and technology of diagnosing, treating, and preventing disease and traumatic injury, of relieving pain, and of preserving and improving human health, using molecular tools and molecular knowledge of the human body;
3) the employment of molecular machine systems to address medical problems, using molecular knowledge to maintain and improve human health at the molecular scale."
Nanomedicine not only has the potential to change medical science dramatically but to open a new field of human enhancements that is poised to add a profound and complex set of ethical questions for health care professionals. For instance, there is a fine line between medical and non-medical uses of nanotechnology for diagnostic, therapeutic and preventive purposes (e.g. non-medical implants in soldiers). The question of whether nanotechnology should be used to make intentional changes in or to the body when the change is not medically necessary is just one hot topic in a long list of concerns.
According to an expert group of the European Medicines Evaluation Agency Source ("Reflection paper on nanotechnology-based medicinal products for human use"; pdf), "the majority of current commercial applications of nanotechnology to medicine is geared towards drug delivery to enable new modes of action, as well as better targeting and bioavailability of existing medicinal substances. Novel applications of nanotechnology include nanostructure scaffolds for tissue replacement, nanostructures that allow transport across biological barriers, remote control of nanoprobes, integrated implantable sensory nanoelectronic systems and multifunctional chemical structures for drug delivery and targeting of disease."
The medical advances that may be possible through nanotechnology range from diagnostic to therapeutic, and everything in between. A recent ObservatoryNano report lists nanotechnological applications in health and medicine (pdf). The two main areas in nanomedicine are:
In the past few decades, imaging has become a critical tool in the diagnosis of disease. The advances in the form of magnetic resonance and computer tomography are remarkable, but nanotechnology promises sensitive and extremely accurate tools for in vitro and in vivo diagnostics far beyond the reach of todayís state-of-the-art equipment.
As with any advance in diagnostics, the ultimate goal is to enable physicians to identify a disease as early as possible. Nanotechnology is expected to make diagnosis possible at the cellular and even the sub-cellular level.
Quantum dots in particular have finally taken the step from pure demonstration experiments to real applications in imaging. In recent years, scientists have discovered that these nanocrystals can enable researchers to study cell processes at the level of a single molecule. This may significantly improve the diagnosis and treatment of cancers. Fluorescent semiconductor quantum dots are proving to be extremely beneficial for medical applications, such as high-resolution cellular imaging. While quantum dots could revolutionize medicine, unfortunately, most are toxic. However, recent studies conducted at the University of California, Berkeley, have shown that protective coatings for quantum dots may eliminate toxicity.
In terms of therapy, the most significant impact of nanomedicine is expected to be realized in drug delivery and regenerative medicine. Nanoparticles enable physicians to target drugs at the source of the disease, which increases efficiency and minimizes side effects. They also offer new possibilities for the controlled release of therapeutic substances. Nanoparticles are also used to stimulate the bodyís innate repair mechanisms. A major focus of this research is artificial activation and control of adult stem cells.
Peptide amphiphiles that support cell growth to treat spinal cord injury; magnetic nanoparticles and enzyme-sensitive nanoparticle coatings that target brain tumors; smart nanoparticle probes for intracellular drug delivery and gene expression imaging, and quantum dots that detect and quantify human breast cancer biomarkers are just a few of the advances researchers have already made.
Interestingly enough, there could be massive shifts in economic value among pharmaceutical companies. While the new nanomedicines open up enormous market and profit potentials, entire classes of existing pharmaceuticals such as chemotherapy agents worth billions of dollars in annual revenue would be displaced.
Other areas that are increasingly attracting interest from nanotechnology researchers are tissue engineering, nanosurgery, and nanoparticle-enabled diagnostics and drug delivery (read more: "A closer look at nanomedicine").