Nearly 250 nanomedicine products are being used or tested in humans, according to a new analysis that identified emerging trends in this sector. But experts caution that the long-term impact of nanomedicine products on human health and the environment is still uncertain.
This study, published in the January 2013 issue of the Nanomedicine: Nanotechnology, Biology, and Medicine Journal, catalogued over 360 experimental or approved medical products that contained any material less than 300 nanometers in size. The study authors conducted an extensive web search, making this state-of-the art analysis, one of the most comprehensive of its kind.
"Nanotechnology offers potential developments in pharmaceuticals, medical imaging and diagnosis, cancer treatment, implantable materials, tissue regeneration, and even multifunctional platforms combining several of these modes of action," said study lead author Michael L. Etheridge, a PhD candidate at the Institute for Engineering Medicine at the University of Minnesota in Minneapolis.
"Nanomedicine is still in an early state," he added. "Although all the applications identified represent significant technological advancements, they are only scratching the surface of the potential available."
"We are still trying to understand how [nanomedicine products] behave in the body, how they get eliminated, or whether there are issues of toxicity," cautioned Warren C.W. Chan, a professor at the Institute of Biomaterials and Biomedical Engineering at the University of Toronto in Ontario and co-founder of Cytodiagnostics, a nanotechnology company, who was not involved with this study. "There are a lot of promises of this emerging field but it requires patience to develop them properly."
Nanotechnology is the research and control of materials at the nanoscale, which ranges roughly from 1 to 100 nanometers, according to the National Nanotechnology Initiative website. One nanometer is a billionth of a meter. Hemoglobin, the protein that carries oxygen in our red blood cells, is 5 nanometers in diameter. A growing number of nanoscale drugs and devices are being used to detect medical conditions earlier and better treat diseases.
This analysis identified several key trends in the nanomedicine sector.
"During the last decade, there has been more development of devices incorporating nanomaterials compared to development of biological products," said study senior author, Dr. J. Jeffrey McCullough, a professor of laboratory medicine and pathology at the University of Minnesota Medical School in Minneapolis. "In vitro testing and in vivo imaging were the most prominent categories, followed by in vivo device coatings and bone substitutes."
Much of the work focuses on cancer treatment but most of this is still in the research phase, he said, noting that they found a dramatic drop in the number of nanomedicine products beyond Phase II clinical trials.
"Many developing drug-delivery platforms take advantage of liposome or emulsion formulations," he said. Nano-formulated drugs accounted for sales of $3 billion in 2006, according to The Nanotech Report, 5th Edition, published by Lux Research.
Their analysis indicates that nanomedicine biologicals -- medical therapies that contain sugars, proteins, nucleic acids or cells -- are poised to represent a larger segment of the field than they have in the past, Etheridge said.
"Nanoparticles are also being used to enhance imaging techniques," he said, adding that passive and active targeting of diseased cells will continue to be an important focus in nanomedicine.
The study authors found two examples of implantable soft-tissue scaffolds with nanostructured surfaces and concluded that, "it is likely that nanomaterials will be critical in developing these surfaces and structures required for ex vivo tissue growth and implantation of engineering tissues."
"Much of the forecasted promise of nanotechnology in medicine takes the form of smart technologies," Etheridge said, citing platforms in development that can target, diagnose, and administer treatment for different disease states.
"The next phases of development in nanomedicine are likely to take advantage of combined applications," he said. Two ways this could happen is by using nanomedicine in combination with current treatments or applying single nanomedicine applications for multiple modes of action, like diagnosis and treatment.
While more nanomedicine products are becoming available to consumers, big questions remain about their long-term impact on the environment and human health, experts say.
"The great unknown in nanotechnology is whether the increased production, handling and exposure of nanomaterials and products will lead to adverse effects in humans and the environment," said Dr. W. Shane Journeay, a Toronto-based physician and nanotoxicology consultant, who was not involved with this study. "Toxicity could be the limiting factor to the commercial success and public acceptance of nanotechnology based products."
"At present, those wishing to commercialize, invest in, or regulate nanotechnology do not have the resources in which to guide the decision making with respect to human and environmental health," he said. "Human health and environmental impacts will directly relate to the financial success of a product."
Disclosure(s): Julielynn Wong, MD, conducted nanotoxicology research while teaching nanomedicine at the College of Nanoscale Science and Engineering of the University at Albany - State University of New York. Dr. Wong recently co-authored "The Clinical Nanomedicine Handbook." She has no investments or direct commercial relationships for nanomedicines or other nanoscale products in this article.
Follow Julielynn Wong, M.D. on Twitter: www.twitter.com/julielynnwong