Although nanomedicine has no official definition yet, most experts describe it as using nanometer-sized particles -- which are thousands of times thinner than a human hair -- to detect and treat diseases at the molecular level. As it stands now, the majority of commercial nanoparticle applications in medicine are geared towards drug delivery, but the real goal of nanomedicine is to create medically useful devices that can function inside the body.
There are some developments in directing and remotely controlling the functions of nano-probes, for example driving magnetic nanoparticles to the tumour and then making them either to release the drug load or just heating them in order to destroy the surrounding tissue. The major trend in further development of nanomaterials is to make them multifunctional and controllable by external signals or by local environment thus essentially turning them into nano-devices.
Although they are tiny, nanoparticles may well become one of the most significant new products in the biomedical field thanks to three Indian American researchers at University of Missouri-Columbia, who have developed a procedure to make them that is 240 times faster than previous methods.
Kattesh Katti, professor of radiology, physics and a senior research scientist at the MU Research Reactor; Raghuraman Kannan, research assistant professor of radiology and Kavita Katti, senior research chemist in radiology, have reduced the time to create gold and silver nanoparticles at room temperature to five to 10 minutes.
Today, nanoparticles are used in applications as varied as making laundry detergent to medicines. However, for them to be beneficial in biomedical applications, they must be manufactured quickly under biologically friendly conditions. Currently that process takes 20 to 40 hours.
"If nanoparticles are to be used for optical imaging within the body, it is pivotal to be able to generate silver nanoparticles at a specific site within the body almost instantaneously," Kattesh Katti said. "Methods that require excessive heating for long durations will have limited biomedical utility."
Gold nanoparticles are biologically benign and are used to make biosensors for disease detection, produce electronic materials and treat cancer. Silver nanoparticles have potential applications in diagnostic biomedical optical imaging. Silver nanoparticles also are extensively used as anti-bacterial agents in the health industry, food storage, textile coatings and a number of environmental applications. They are superior to nanoparticles made of other materials because of their imaging capabilities and their resonance.
Katti said nanoscience represents an exciting new area of science for the 21st century. He says his lab will be able to supply nanoparticles for other research labs. "Our objective is to develop our own research and student training in nanoscience and nanotechnology and assist with research across the campus," Katti said. "Once we have done that, we will certainly be able to help researchers all across the United States."
Working with MU Physics Professor Meera Chandrasekhar, Assistant Professor of Physics Suchi Guha, and graduate assistant Vijaya Kattumuri, Katti and Kannan also are examining the light imaging properties of nanoparticles.
BREAKTHROUGH FOR WILSON’S DISEASE
Meanwhile another discovery by the same team has led to the development of a new drug for the treatment of Wilsonīs Disease, a liver disorder. Katti said animal trials of the drug "MU-TAM" have been successful and he expects human trials to follow after obtaining an industrial sponsor for the pharmaceutical.
Typically, water forms small ring structures with six or eight sets of water molecules. The researchers found structural evidence for a large water ring structure with 18 sets of water molecules when water was mixed with the experimental pharmaceutical. After further testing, the researchers discovered MU-TAM was an amphiphile, a molecule with both hydrophobic, or water repelling, and hydrophilic, or water loving, qualities.
In patients with Wilsonīs Disease, the liver is unable to rid itself of excess copper. Katti says too much copper can produce "free radicals" in the body that attack the patientīs DNA, protein and tissue. MU-TAMīs amphiphile attributes help the body fight Wilsonīs Disease directly.
"The hydrophobic portion of this drug delivers the drug to the liver to rid it of the excess copper," Katti said. "The water loving, or hydrophilic portion, then carries excess copper out of the liver through the urine. The cleansing properties of MU-TAM will have important implications in the treatment of various other diseases that affect the liver."
Katti says animal trials were conducted on pigs in cooperation with Stan Casteel, MU professor of veterinary medicine. Katti said the pigs provided an ideal test model because they are so similar to humans in size and physiology. Following the issuance of a patent from the federal government, Katti hopes to secure an industrial sponsor to support human trials within the next three to five years.
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