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Polymer coatings test for cancer, prevent infections, detect bacterial contamination

Polymer coatings test for cancer, prevent infections, detect bacterial contamination

03-Aug-17

A range of polymer coatings are available in the form of lubrications, anti-microbial liquids, water repellent polymers.  Each variant is used for different applications. Besides sanitation, the other concerns about coatings are allergenic substances, risk of new infections, FDA compatibility standards, resistance to microbe absorption and transference. Research has seen developments in coatings to enhance performance of devices.

For many types of implants, including stents, endotracheal tubes, urinary catheters and vascular grafts, there is a risk of infection. Some present issues with blood clotting as well. Infections from medical implants can pose major problems to public health. Dr. Hitesh Handa, an assistant professor at the University of Georgia in the School of Chemical, Materials, and Biomedical Engineering and his team are developing polymer coatings for medical implants to reduce health risks. These coatings help prevent growth of bacteria clusters, called biofilm, which can form on medical implants and lead to infection. This work involves a lot of different people including collaborators in Michigan, some UGA students and the Veterinary School at UGA.
The my group is trying to develop coatings that can release nitric oxide gas, which can mimic what the body does to prevent clotting and infection. Nitric oxide is a gas that is produced in the human body. The gas is released by the veins and arteries in order to prevent platelet activation, which helps prevent blood clotting. Nitric oxide is also released in the sinuses and by white blood cells to fight harmful bacteria. Handa said by “minimally hurting” animals, the research team will be able to find out if the medical coatings are really working.
A timeline for when people can expect to have access to these type of treatments on a large scale is largely an estimation at this point.

Australian scientists have developed a polymer coating that can test for bladder cancer more simply and much cheaper than current invasive techniques. Professor Krasi Vasilev, from the University of South Australia's Future Industries Institute, told Plastics News that his team was researching antibiotic properties of polyoxazoline-based polymers and discovered a polymeric compound that will bind to cancer-specific antibodies in urine. That enabled the researchers to develop a portable, non-invasive devise to test for bladder cancer. Vasilev said bladder cancer is difficult to diagnose and the probability of recurrence is high — about 75% within five years.
Survivors have regular cytoscopies, which involve inserting a thin tube with a camera attached through the urethra to the bladder. This is a very invasive procedure, is expensive, requires hospitalization and can lead to complications. The new test exposes a urine sample to a 20-nanometer-thick polymer coating on a substrate. The compound binds to antibodies when it recognizes a protein on the surface of cancer cell membranes. The device uses biosensors and micro-optics to identify the presence of those cells.
The research is led by Adelaide, South Australian-based SMR Technologies, a unit of SMR Automotive Australia Pty. Ltd. Vasilev said the polyoxazoline-based polymer technology, which has been patented, has potential for other medical uses. Its antibacterial properties may be useful for implantable devices. Valisev said almost half of hospital-based infections occur after medical devices, like artificial knees and hips, are implanted.
Infections caused by bacterial colonization of medical devices are a substantial problem for patients and the health-care industry but the polyoxazoline coatings are a potential solution. Vasilev is also researching ways to use them in antifouling applications for ships. He said "undesirable biological adhesion" also has detrimental effects in food processing and a wide range of other industries. Using plasma polymerization to form nanoscale coatings on a solid substrate means no prior substrate preparation is required and eliminates use of organic solvents "so it's a greener technology," Vasilev said.

A team is working to reduce infections with a smart polymer that changes color and activates natural antimicrobial enzymes when bacterial contamination is detected.
Constant exposure to salivary bacteria makes dental tools, such as reusable X-ray imaging plates, ideal environments for virulent biofilms. Associate Professor Niveen Khashab, her Ph.D. student Shahad Alsaiari and colleagues from the University's Advanced Membranes and Porous Materials Center realized that switching to gold nanoparticles could give antimicrobial coatings detection capabilities—these tiny crystals have sensitive optical properties that can be tuned to spot specific biomolecular interactions. But incorporating them safely into polymers required new types of nanofillers.
The team's approach uses gold nano clusters treated with lysozyme enzymes that have innate defenses against pathogens, such as Escherichia coli, commonly known as E. coli. They attached these colloids to the surface of slightly larger, porous silica nanoparticles stuffed with antibiotic drug molecules. Normally, this gold-silica complex emits glowing, red fluorescent light. But when the lysozyme units encounter bacteria, a strong attraction for cell walls rips the gold nanoclusters from their silica partners—an action that simultaneously switches off fluorescence and releases the antibiotic cargo.
Blending experiments revealed the gold-based nanofillers integrated thoroughly into polymer composites and exhibited minimal leaching during trials with E. coli. Khashab attributes these favorable polymer interactions to the sharp exposed edges of gold clusters on the silica spheres. The researchers tested their concept by comparing X-ray dental plates with and without the smart polymer coating. Both samples yielded the same high-resolution images of teeth and bone structure. However, only the coated plate enabled rapid visual assessment of bacterial contamination, simply by illuminating the device with a UV-lamp and looking for color change. Successful release of the antibacterial agent also drastically decreased biofilm buildup.

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