Team of students invents device to cut dialysis risk

Posted by Biomechanism 

Johns Hopkins University graduate students have invented a device to reduce the risk of infection, clotting and narrowing of the blood vessels in patients who need blood-cleansing dialysis because of kidney failure.

Caption: This illustration shows the Hermova Port attached to the femoral vein beneath the skin, where the student inventors say the risk of infection is reduced. Credit: Johns Hopkins University

The device, designed to be implanted under the skin in a patient’s leg, would give a technician easy access to the patient’s bloodstream and could be easily opened and closed at the beginning and end of a dialysis procedure.

The prototype has not yet been used in human patients, but testing in animals has begun.

The students learned about the need for such a device last year while accompanying physicians on hospital rounds as part of their academic program. They watched as one doctor performed a procedure to open a narrowed blood vessel at a kidney patient’s dialysis access site. They learned that this narrowing was a common complication facing kidney patients.

The students discovered that kidney failure each year requires 1.5 million people globally and 350,000 in the United States alone to undergo regular hemodialysis to prevent a fatal buildup of toxins in the bloodstream. The students also learned that the three most common ways to connect the machine to a patient’s bloodstream work only for a limited time because of problems with infection, blood clots and narrowing of the blood vessels. Current dialysis access options are “grossly inadequate,” contributing to increased healthcare expenses and, in some cases, patient deaths, the students say.

Caption: An illustration of a closeup view of the Hemova Port, connected below the skin in the patient's leg to a femoral vein. Credit: Johns Hopkins University

To address these problems, the students developed an access port that can be implanted in the leg beneath the skin, reducing the risk of infection. The Hemova Port’s two valves can be opened by a dialysis technician with a syringe from outside the skin. The technician can similarly close the valves when the procedure is over, an approach that helps avoid infection and clotting. The device also includes a simple cleaning system, serving as yet another way to deter infections.

Currently, most dialysis access sites are in the arm or the heart. The Hemova device instead is sutured to the leg’s femoral vein, avoiding the unnaturally high blood flows that cause vessel narrowing when dialysis machines are connected to veins and arteries in the arm. The student inventors say the Hemova Port’s leg connection should allow the site to remain in use for a significantly longer period of time.

The port won a $10,000 first prize for Johns Hopkins graduate students in the 2011 ASME Innovation Showcase. The competition, involving 10 collegiate teams, was conducted in Texas earlier this month at the annual meeting of ASME, founded in 1880 as the American Society of Mechanical Engineers. Judges based their awards on technical ingenuity, quality of business plans, potential for success in the marketplace and other factors.

Caption: The Hemova Port was developed by Johns Hopkins biomedical engineering graduate students, from left, Peter Li, Thora Thorgilsdottir, Sherri Hall, Mary O'Grady and Shishira Nagesh. Credit: Will Kirk/JHU

The five biomedical engineering students on the team were enrolled in a one-year master’s degree program in the university’s Center for Bioengineering Innovation and Design. Sherri Hall, Peter Li, Shishira Nagesh, Mary O’Grady and Thora Thorgilsdottir all recently graduated, but Li has remained in Baltimore to form a company that will continue to test and develop the project.

With help from the Johns Hopkins Technology Transfer staff, the team has filed for three provisional patents covering their technology. The patents list the five students and three medical faculty advisers as the inventors.

“Winning first-place in the ASME competition is a great honor,” Li said. “The award and the recognition will go a long way toward helping to continue further research, and we hope it will bring us closer to the day when our device is available to help dialysis patients.”

The Hemova team has applied for a $50,000 grant to conduct more animal testing in the coming months. Clinical trials involving human patients could begin as soon as 2013, the students said.

Nano-crystals make solar cells

Nano-crystals make solar cells

FRESHSCIENCE

Solar cells can be used to assemble large scale panels. Image: FernandoAH/iStockphoto Australian researchers have invented nanotech solar cells that are thin, flexible and use 1/100th the materials of conventional solar cells. Printable, flexible solar cells that could dramatically decrease the cost of renewable energy have been developed by PhD student Brandon MacDonald in collaboration with his colleagues from CSIRO’s Future Manufacturing Flagship and the University of Melbourne’s Bio21 Institute. Their patented technology is based on inks containing tiny, semiconducting nanocrystals, which can be printed directly onto a variety of surfaces. By choosing the right combination of ink and surface it is possible to make efficient solar cells using very little material or energy. “The problem with traditional solar cells,” Brandon says, “is that making them requires many complex and energy intensive steps.” “Using nanocrystal inks, they can be manufactured in a continuous manner, which increases throughput and should make the cells much cheaper to produce.” Nanocrystals, also known as quantum dots, are semiconducting particles with a diameter of a few millionths of a millimetre. Because of their extremely small size they can remain suspended in a solution. This solution can then be deposited onto a variety of materials, including flexible plastics or metal foils. It is then dried to form a thin film. Brandon and his colleagues discovered that by depositing multiple layers of nanocrystals they can fill in any defects formed during the drying process. The result is a densely packed, uniform film, ideal for lightweight solar cells. The nanocrystals consist of a semiconducting material called cadmium telluride, which is a very strong absorber of light. This means that the resulting cells can be made very thin. “The total amount of material used in these cells is about 1 per cent of what you would use for a typical silicon solar cell. Even compared to other types of cadmium telluride cells ours are much thinner, using approximately one-tenth as much material,” Brandon says. The technology is not limited to solar cells. It can also be used to make printable versions of other electronic devices, such as light emitting diodes, lasers or transistors. For his work Brandon has received the 2010/11 DuPont Young Innovator’s Award and has had his work published in the journal Nano Letters. Brandon MacDonald is one of 16 early-career scientists presenting their research to the public for the first time thanks to Fresh Science, a national program sponsored by the Australian Government.

Preterm babies risk kidneys

Preterm babies risk kidneys

MONASH UNIVERSITY

"Preterm babies had far fewer nephrons - the 'building blocks' that make our kidneys." Image: MichaelBlackburn/iStockphoto Babies born prematurely could be at greater risk of developing kidney diseases later in life according to a landmark study investigating the impacts of preterm birth on kidney development. The Monash University study is identifying new strategies for minimising the consequences of being born preterm, which accounts for around eight per cent of births each year in Australia. By comparing the kidneys of babies born prematurely with those born after the full nine-month gestation, the research team, led by Associate Professor Jane Black from the Department of Anatomy and Cell Biology, identified that preterm babies had far fewer nephrons – the ‘building blocks’ that make our kidneys. “An average person has around 800,000 to 1.5 million nephrons and the number we have at birth is the number we have for life,” Associate Professor Black said. “We have shown that babies born preterm have less nephrons, in the range of 400,000 – 600,000. This is because nephron development occurs in the last few weeks of pregnancy, so babies born preterm have not had time to complete the developmental process.” “Even moderate preterm babies, those born within four weeks of full gestation, who were previously considered to have achieved ‘normal’ development, were found to have far fewer nephrons and underdeveloped kidneys.” Associate Professor Black said the findings were of critical importance because of the known link between having fewer nephrons and renal, or kidney, diseases. “The more nephrons you have the more ‘solid’ a structure your kidneys will have. When we look at kidneys that have fewer nephrons, abnormalities are present, which indicates that preterm babies could be much more susceptible to renal disease and possible kidney failure later in life,” Associate Professor Black said. “Particularly in the last 30 years, we have had great successes with preterm births and today even babies born 26 weeks premature have an 80 per cent chance of survival. Preterm babies now account for around eight per cent of births in Australia and 12-14 per cent in the USA.” “Because the improvements in survival rates are only recent, we have not yet witnessed the impact of premature births on the health system.” Associate Professor Black has received two prestigious grants from the National Health and Medical Research Council (NHMRC) administered by Monash University. “The NHMRC funding will enable Monash researchers to study the development of kidneys and hearts in preterm babies,” Associate Professor Black said. “With the kidney studies, our aim is to develop strategies that will ensure these babies have the highest number of nephrons possible, in order to give them the best start in life.” “We need to know the things that restrict nephron development and are looking at a range of factors, including blood pressure, respiration, medications taken during pregnancy, and care following birth.” “We are also working with Indigenous communities in the Northern Territory so we can make a comparison between the renal development of Indigenous and non-Indigenous babies. This is timely as Indigenous people have 17 times greater incidence of renal disease than the non-Indigenous population,” said Associate Professor Black.