“Man is the center of the universe. We stand in the middle of infinity between outer and inner space, and there’s no limit to either.”
-Fantastic Voyage, 1966
In 1959, physicist Richard Feynman gave a talk at Caltech titled “There’s Plenty of Room at the Bottom
,” wherein he first introduced the concept of creating devices at the molecular level by manipulating individual atoms and molecules. It wasn’t until years later that the term “nanotechnology” was coined to refer to this concept, yet its principles had invoked imaginations everywhere, including Hollywood, and, in 1966, the film Fantastic Voyage
was released. In the movie, a submarine with a medical team onboard is shrunk to become microscopic and injected into a scientist with the intention of treating his life-threatening blood clot. Since its release over 40 years ago, countless references to this film have been made in literature, television, and cinema, and a remake is slated to be released in 2010, which will perhaps spark interest in nanotech among future generations.
While the concept of shrinking humans is quite fantastic and unrealistic (at least for the foreseeable future), scientists have already developed tiny vessels that can hunt down diseased cells and deliver precise drug doses. These tiny vessels are called nanocapsules or nanoparticles, and Russell Mumper, PhD, UNC Center for Nanotechnology in Drug Delivery, UNC Lineberger Comprehensive Cancer Center, has used them to overcome chemoresistance in mouse models. Dr. Mumper and his team found that when doxorubicin or paclitaxel were delivered using lipid nanocapsules, the growth of multidrug-resistant ovarian cancer lesions stopped completely in the mouse models that they examined, whereas these drugs were found to be ineffective when administered through conventional means. His research
is published in the May 1, 2009 issue of Cancer Research
, and he took the time to answer some of our questions on his findings and share his thoughts on nanotechnology and its medical applications.
Overcoming chemoresistance: A conversation with Dr. Mumper How do you think nanotechnology will impact medicine over the next decade—do you see this as the next frontier?
Nanotechnology is not new. In fact, it has been around for decades and arguably for much longer; however, it has more recently captured the imagination and interest of scientists and lay people alike. As of 2007, there were about 200 companies focusing on the use of nanotechnology to address medical issues. There are already over 40 nanomedicine products on the market with sales exceeding $7 billion annually. The use of nanotechnology for drug delivery captures the largest percentage of this market, about 78% of sales. I believe it is one of two next frontiers, those being the really small (nanotechnology) and the really large (outer space).How do nanocapsules work?
Our laboratory has been focused over the past decade on trying to put very potent cancer drugs in nanoparticles so that these small carriers can be injected into the body and potentially targeted to tumors. This endeavor has been challenging for many labs, including ours, since the task is multifaceted and there are many obstacles. We have discovered a very simple process to make oil-filled nanocapsules. Unlike nanoparticles that are solid throughout, these nanocapsules have a shell with a liquid oil on the inside. The engineering process to make the nanocapsules is rapid, cost-effective, and can be completed in a few minutes in one vessel. All of the materials used to make them are already in pharmaceutical products. The oil on the inside of the nanocapsules can dissolve the cancer drugs in high concentration, and the drugs remain stable in the vial or when injected into the bloodstream. Over time, the drug is released from the nanocapsules and the oil in the nanocapsules is actually metabolized by the body and used as nutrients.What were some of the key outcomes of your study?
Many types of cancers develop mechanisms to become resistant to otherwise potent cancer drugs. The most well-known mechanism of resistance is where a protein on the surface of the cells or sometimes in the cells can quickly and extensively pump the drug out of the cell. Resistance is a significant problem and leads to recurrence. The only solution is to choose a different drug and hope that the new drug can provide benefit before the tumor becomes resistant to it.