Author: Natasha Hochlowski
Institution: Princeton University
One of the most difficult obstacles for cancer researchers to overcome in the past several decades has been the development of methods to detect cancerous cells. If such a method could be perfected, diseased cells could be easily identified and treated. What would this mean for cancer patients? Could this help doctors move closer to finding a "cure for cancer"? The answers to these questions are being explored by Dr. Issa A. Katime and his research team at the Department of Physical Chemistry at the University of the Basque Country (UPV/EHU).
Dr. Katime's research team has worked to develop intelligent nano-hydrogels, small particles that can detect areas that are diseased and release medication to these specific cells. Previous to now, diseased cells were nearly impossible to target and medicine could only be delivered to a general site, affecting both healthy and unhealthy cells. Professor Robert Langer from the Departments of Biological and Chemical Engineering at the Massachusetts Institute of Technology stated that the lack of ability to distinguish cancerous from non-cancerous cells is what makes it very difficult to target drugs to the diseased cells. He believes that "If you detect cancer and deliver the drug to the site, it should be safer and more effective."
These nanohydrogels are a new advancement in the field of nanotechnology. Nanotechnology, according to the National Cancer Institute, is "the creation of useful materials, devices, and systems used to manipulate matter at an incredibly small scale." "Small" is somewhat of an understatement, as devices on the nanomolecular scale tend to be about the size of 1/1000 of a human hair.
The hydrogels being used in cancer treatments are polymers, small molecules linked by covalent, or electorn-sharing, bonds in the shape of a net. They can detect changes in pH, making it easy to determine whether cells are cancerous. Blood generally has a pH of around 7.4,close to that of water,whereas cancerous zones have more acidic pHs, between 4.7 and 5.2,closer to the pH of coffee. The hydrogels contain folic acid which "tricks" cancerous cells into allowing the hydrogels inside the cells. Once inside, the change in pH causes the hydrogels to swell and release whatever pharmaceutical drug is contained within, thus treating the disesased cells.
But according to Professor Chun Li of the Department of Experimental Diagnostic Imaging at the University of Texas M.D. Anderson Cancer Center in Houston, "There are many biological barriers to effective use of nanoparticles, with the liver and spleen being the most important." One of the biggest problems with using nanotechnology to treat cancer is that once the particles containing the pharmaceuticals enter the body, the patient's immune system will identify the particles as foreign threats and target them for destruction. However, if the particles are small enough, they cannot be detected. Dr. Katime's team has developed a technique to manufacture hydrogels that are only 15-30 nanometers, or about the size of a virus,so small that they can safely enter the body without being detected and destroyed. Then, after serving their purpose, they will pass through the membrane of the kidney, eventually being exreted with the patient's urine.
In mid-February of 2009, teams led by Dr. José María Teijón, Professor at the Faculty of Medicine at the Complutense University in Madrid and Dr. Antonio Quintana, Professor at the Faculty of Medicine at the UPV/EHU, began "in vivo" trials of these nanoparticles. "In vivo," Latin for "within the living," indicates that these experiments are being done on living tissue so as to project the effects and level of success when used in humans.
If proven successful, the hydrogels may greatly aid the performance of cancer treatments. Li states that "active targeting of nanoparticles to tumors is the Holy Grail of therapeutic nanotechnology for cancer." Not only will these hydrogels affect treatment of cancer, but they may be useful for treating other diseases as well. Currently, people suffering from tuberculosis need to receive anti-tubercular pharmaceuticals several times a day. However, with the application of this new discovery, the medicine may need to be injected much less frequently since the distribution of the pharmaceuticals would be regulated by the nano-hydrogels.
The medical team is now awaiting a patent on the nano-hydrogels, forthcoming in the next several months. After the in vivo trials are concluded, the polymers will be ready to be further tested for eventual release on the market. Although the research teams still have a lot of tests to perform, we may one day see these tiny molecules present the solution to one of medicine's biggest problems.