9 February 2012
Nanomaterials have achieved major importance in the health care industries. These are already used in surgical gowns, bedding, and portable items to minimize the risk of pathogen growth and transfer. Nanomaterials are increasingly used for diagnostic procedures, most significantly, according to the Nanotechnology Institute, in the diagnosis of arteriosclerosis and Alzheimer’s disease. The capabilities of semiconducting nanocrystals (quantum dots) have led to advances in optics technology that have enabled health-care professionals to view almost any part of or specific organ in the human body. Nanomaterials also have a major role in the circuitry of microelectronic instruments. What has not been developed as fully is the use of nanomaterials as potential sensors for therapeutic procedures.
Another possible benefit of nanomaterials is their high surface area, which allows for faster kinetics and offers possibilities for extremely small quantities of material to act directly as biocides against bacterial and viral organisms. Already it has been demonstrated in-vitro that nanometal particles can be highly cytotoxic. Research still needs to be done so that the cytotoxic effects are directed at target cells and harmful organisms and not at healthy cells. Nanomaterials have also been shown in research to have beneficial effects such as in the regeneration of nerve cells after traumatic damage.Initial efforts in using internal sensors for therapy have focused on photodynamic procedures. These therapies used overly energetic portions of the electromagnetic spectrum and problems arose specifically because the high energy levels split off triplet oxygen, nitric oxide, and other radical species that cause serious physiological side effects. What is proposed is that sensor technology be adapted to convert specific forms of energy to achieve desirable therapy while minimizing undesirable side effects, particularly from unwanted chemical bond scission.
Other possibilities include nanomaterials acting as carriers for therapeutic materials. One of interest is silver, which is known to absorb oxygen without reacting with it, and thus can be used as a carrier for the gas. It has possible benefits for respiratory therapy, but can also possibly be used as a temporary substitute for hemoglobin. Using nanomaterials as carriers for other medical chemicals and drugs to get more precisely targeted therapies offers additional scope for research.
Major barriers to adoption of nanomaterials are concerns regarding possible harmful effects the molecules might have on humans and on the environment. Nanomaterials have been used for many years without untoward incident, and much recent research has convinced regulatory agencies, such as the EPA that they are safe. Thus, these agencies are starting to accept nanomaterials for registration if they are proven to be both effective and safe. The scope of materials that can be fabricated into nano devices is also expanding. Research in academic laboratories has already shown that polymeric and biochemical materials, in addition to metals and inorganic chemicals, can be made in nano forms and it is very likely that these too will soon achieve commercial utility. Access to nano as well as micro medical devices can increase the possibilities for successful and safer medical procedures. Much of the technology that would be developed would take advantage of the fact that infectious microorganisms and cancerous tissues tend to be kinetically more active than healthy cells. More often than not, the sensor can be selectively placed or absorbed onto the target organism or tissue and the sensor activated with an initiator to give off heat (hyperthermia) or some other therapeutic agent.
Dr. Jeffrey R. Ellis has been active in medical device research for over thirty years and has been a frequent contributor to MD+DI magazine. He administers research projects on nanomaterials especially on nanosilver on behalf of silver industry trade associations. He is also active in helping shape regulatory policies regarding nanomaterials in both the United States and Europe.