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New nanoparticle "nose" sniffs out cancer earlier |
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Jun 29, 2009 at 05:30 PM |
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Researchers at the University of Massachusetts, Amherst and the Georgia Institute of Technology have developed a novel "chemical nose" based on an array of nanoparticles and polymers that can differentiate not only between healthy and cancerous cells but also between metastaic and non-metastatic cancer cells (Proceedings of the National Academy of Science, 23 June online). The research team, led by Vincent Rotello at Amherst, designed the new detection system by combining three gold nanoparticles that have special affinity for the surface of chemically abnormal cells, plus a polymer known as PPE, or para-phenyleneethynylene. As an indicator PPE fluoresces or glows when displaced from the nanoparticle surface. By adding PPE bound with gold nanoparticles to human cells incubating in wells on a culture plate, the researchers were able to induce a response called "competitive binding." Cell surfaces bind the nanoparticles, displacing the PPE from the surface. This turns on PPE's fluorescent switch. Cells are then identified from the patterns generated by different particle-PPE systems. Rotello says the chemical nose approach is so named because it works like a human nose, which is arrayed with hundreds of very selective chemical receptors. These bind with thousands of different chemicals in the air, some more strongly than others, in endless combinations. The receptors report instantly to the brain, which recognizes patterns such as, for example, "French fries," or it creates a new smell pattern. Chemical receptors in the nose plus the brain's pattern recognition skills together are extremely sensitive at detecting subtly different combinations, Rotello notes. For example, we can routinely detect the presence of tiny numbers of bacteria in meat that is going bad. Like a human nose, the chemical version being developed for use in cancer also remembers patterns experienced, even if only once, and creates a new one when needed. The team plan further studies in an animal model to see if the chemical nose approach can identify cell status in real tissue. Also, more work is required to learn how to train the chemical nose's sensors to give more precise information to physicians who will be making judgment calls about patients' cancer treatment. But the future is promising, Rotello adds, "We're getting complete identification now, and this can be improved by adding more and different nanoparticles. So far we've experimented with only three, and there are hundreds more we can make." Source: PhysOrg.com |
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Multifunctional nanoparticles seek out early pancreatic cancers |
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Jun 29, 2009 at 04:43 PM |
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Pancreatic cancer has a very low survival rate (less than 5% after 5 years) because it is usually diagnosed at an advanced stage. The initial symptoms, such as pain, jaundice, or weight loss, often do not allow the disease to be detected early enough for surgery and chemotherapy to be effective. Researchers at Emory University in the United States, led by Dr Lily Yang, Dr Hui Mao, and Dr Shuming Nie, have recently created nanoscale tools for the early diagnosis of pancreatic cancer by attaching a molecule that binds specifically to pancreatic cancer cells to iron oxide nanoparticles that are clearly visible under magnetic resonance imaging (MRI). When tested in mice with implanted human tumors, the particles also can be seen by scanning the mice with a specialized camera because the particles are studded with near-infrared dyes. The iron oxide particles have a core 10nm in diameter with a polymer coating. The molecule that allows the particles to discriminate between pancreatic cancer cells and healthy cells is an engineered small protein based on a natural protein found in humans, urokinase plasminogen activator (uPA), which binds to its receptor (uPAR) on cancer cells. The researchers found that particles coated with a fragment of uPA are taken up by pancreatic cancer cells and not by normal pancreatic tissue. Tumour endothelial cells, which line blood vessels, also take up the particles, and a low signal is seen in liver and spleen. Tumours as small as 1mm across can be detected by MRI or optical imaging. The technology now needs to be refined so that it is ready to test in patients. Groups of patients that are at increased risk of pancreatic cancer, such as those with inherited cancer risk factors, chronic pancreatitis, or new-onset diabetes, could benefit in the future from the new nanoparticle approach. Source: Nanowerk Paper: Gastroenterology, Volume 136, Issue 5, Pages 1514-1525 |
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Novel nanoparticles seek out brain infections |
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Jun 29, 2009 at 04:14 PM |
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Major brain infections such as meningitis and encephalitis are a leading cause of death, hearing loss, learning disability and brain damage in patients. Researchers at the Institute of Bioengineering and Nanotechnology (IBN) have developed novel peptide nanoparticles that can pass readily through the blood-brain barrier to parts of the brain infected by bacterial infections such as meningitis. IBN's peptide nanoparticles contain a membrane-penetrating component that enables them to pass through the blood brain barrier to the infected areas of the brain that require treatment. The ability of IBN's peptide nanoparticles to traverse the blood brain barrier may therefore offer a superior alternative to existing treatments for a range of brain infections. According to on of the lead researchers, Dr Yiyan Yang, the IBN oligopeptide has a unique chemical structure that forms nanoparticles with membrane penetrating components on their surface. Dr Yang also explains that the nanoparticles can easily enter bacteria, yeast or fungal cells and destabilize them to cause cell death. For example, the nanoparticles cause damage to bacteria cell walls and prevent further bacterial growth. Pre-clinical tests have shown that IBN's peptide nanoparticles are biocompatible and cause no damage to the liver or kidneys at tested doses. Highly anti-infective, the therapeutic doses of the peptide nanoparticles are expected to be safe for use because they also do not damage red blood cells. Source: Nanowerk Paper: Nature Nanotechnology |
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