Flexible polymer reinforces padding of helmets, shoes- aids shock absorption
A biomechanical engineer is applying his expertise in materials science, mechanical engineering and bioengineering to protect the brain from the forces that cause concussions and traumatic brain injury. He has created a polymer that could diminish the force of helmet-to-helmet hits on a football field or shockwaves from explosive devices on a battlefield. This innovation can be credited to UCLA professor Vijay Gupta. The human head - which encases a 3 lb brain, suspended in cerebral-spinal fluid in the hard shell of the skull –is one of the best shock-absorbing systems. Unfortunately, it was not designed to withstand the shockwaves at a force above 90 Gs, resulting from a collision with a 250 lbs football player wearing a helmet-herein there is an almost 90% probability of a concussion. The impact literally causes a stress wave to pulse through the brain, hit the other side of the skull and rebound back through the brain. These reverberations cause pushing and pulling forces that tear apart tissue like blood vessels and neurons. Concussions can also result from the head being violently shaken. Gupta deduced that if he succeeded in cutting down the level of force, it would help concussion reduction. To improve on the shock-absorbing ability of the standard football helmet without radically changing its design, the team added a 2 mm thick wafer of a firm, but flexible polymer devised to reinforce the helmet’s foam padding. If the helmet is altered too much, the concern is that it might affect how players are forced to play and they might not want to wear it. Gupta and his team have been able to achieve up to a 25% reduction in the force a person would feel. This translates to a similar reduction in the probability of getting a concussion. The material would absorb shock for runners. A significant reduction in shock has been noticed by placing just a 1.5 mm thick layer of the material below the sock liner. Gupta estimates that runners who run 5-10 miles per week could increase the life of their knee cartilage life by 10 to 15 years (depending upon the age of the runners). This is shock absorption is similar to the insoles currently available but with this polymer, it is just one-tenth as thick. Gupta sees possible military applications for the polymer. Soldiers are subjected to powerful shockwaves from explosive blasts on the battlefield, and Gupta thinks adding his polymer to military helmets could help diminish those effects and reduce traumatic brain injuries.
Ferrying chemo drugs to brain tumors via polymer microencapsulation
Chemotherapy suffers from poor targeting and leads to patients absorbing considerably more than is needed to attack their cancers. Brain tumors in particular, are hard to treat with chemo because the blood-brain barrier is very choosy about what it lets through, so even higher doses have to be used. No method currently exists that allows for timed release of the drug in a localized fashion, so the only option is repeated opening of the skull in a lot of cases. One alternative approach that is being investigated is using biodegradable polymers to encapsulate chemo drugs and deliver them in a more targeted fashion to the site of a tumor. Researchers at Penn State have developed a way to produce biodegradable polymer microcapsules that are all of uniform size and shape, and can be injected directly into the brain to degrade as pre-planned by a physician for most effectiveness. Mohammad Reza Abidian, (assistant professor of bioengineering, chemical engineering and materials science and engineering) , working with Pouria Fattahi and Ali Borhan, professor of chemical engineering, looked at using an electrojetting technique to encapsulate BCNU in poly(lactic-co-glycolic) acid, an FDA-approved biodegradable polymer. In electrojetting, a solution containing the polymer, drug and a solvent are rapidly ejected through a tiny nozzle with the system under a voltage as high as 20 kilovolts but with only microamperage. The solvent in the liquid quickly evaporates leaving behind anything from a perfect sphere to a fiber. The researchers tested solutions of polymer from 1% by weight to 10% by weight and found that at 1-2% they obtained flattened microspheres, at 3-4% they had microspheres, at 4-6% they had microspheres and microfibers, at 7-8% they had beaded microfibers and above 8% they obtained only fibers.