Friday, 1 of August of 2014

Category » Biomedical Engineering

Silk-Based Surgical Implants an Orthopedic Innovation

silkscrewThe latest silk-inspired innovation from the lab of biomedical engineering Professor David Kaplan is receiving media attention: silk-protein surgical screws that could transform the way we heal broken bones. Researchers from Kaplan’s lab and Beth Israel Deaconess Medical Center published their findings in the journal Nature Communications this March.

Surgical screws and plates, or “fixation devices” are used to repair fractured bones and are often made of metal alloys or synthetic polymers. However, metal implants place undue stress on the bone, are prone to infection, and must be surgically removed from the body once a fracture has healed. Synthetic screws are designed to be absorbed by the body, but they can be difficult to set and may cause inflammation.

The research team manufactured plates and screws from the silk protein produced by the Bombyx mori (B. mori) silkworm cocoons. A silk solution was cured into molds that produced easily machinable plates and screws. The silk screws are self-tapping, an improvement from conventional resorbable screws that require careful drilling of a screw hole before insertion of the hardware. In vivo tests showed the screws remain fixed in the bone at four and eight weeks with notable improvements in the healing and resorbtion process.

Professor Kaplan told BBC News: “The future is very exciting. We envision a whole set of orthopaedic devices for repair based on this – from plates and screws to almost any kind of device you can think of where you don’t want hardware left in the body.”

Some added benefits to the silk technology over metal fixation devices include decreased sensitivity to the cold and zero interference with X-ray technology or metal detectors. “One of the other big advantages of silk is that it can stabilize and deliver bioactive components, so that plates and screws made of silk could actually deliver antibiotics to prevent infection, pharmaceuticals to enhance bone regrowth and other therapeutics to support healing,” says Kaplan.

This research was supported by the National Institutes of Health (EB002520).

More coverage on this story: TuftsNow, New Scientist, The Telegraph, and Popular Science


Tufts University Alumni Association 2014 Senior Award Honorees

Each year, the Tufts University Alumni Association (TUAA) recognizes members of the senior class for academic achievement, participation in campus and community activities, and leadership. Twelve students are chosen from a pool of nominees for the TUAA Senior Award. This year’s cohort of Senior Award Honorees includes two engineering students: Briana Bouchard and Laura Burns.

Briana BouchardBriana Bouchard will graduate with a Bachelor of Science degree in mechanical engineering. Bouchard served as Corporate Relations Chair and Publicity Chair for Tufts Society for Women Engineers, Tufts Admissions Tour Guide and Engineering Panelist, Senior Representative and Academic Chair for the American Society of Mechanical Engineers, Residential Assistant for Tufts University Office of Residential Life. As a researcher, she designed a medical device to assist in the insertion of IV catheters in babies and children, was part of a team that designed an award winning audio speaker, and has researched the use of silk for breast implants for women who have had mastectomies.


Laura BurnsLaura Burns will graduate with a Bachelor of Science degree in biomedical engineering. At Tufts, Burns was a Stern Family Scholar, was on the Dean’s List all semesters, a member of Tau Beta Pi (Engineering National Honor Society), President and Board Member of the Tufts University Engineering Student Council, Secretary and Board Member for Tufts University Society for Women Engineers, Captain of the Varsity Swim Team, and a volunteer at Tufts University Admissions Office. Burns was a research assistant in Assistant Professor Lauren Black’s Lab, where she worked with tissue engineering of cardiac tissue and design of an optical device to measure the thickness of delicate tissues.


Aldridge Wins NIH New Innovator Award

Bree Aldridge

Bree Aldridge, Assistant Professor of Molecular Biology & Microbiology

Assistant Professor Bree Aldridge has received a 2013 National Institutes of Health Director’s New Innovator Award. Aldridge is an assistant professor in molecular biology and microbiology at Tufts University School of Medicine, a member of the Molecular Microbiology and Immunology program faculties at the Sackler School of Graduate Biomedical Sciences at Tufts, and adjunct assistant professor in biomedical engineering. She has been awarded a five-year, $1.5 million grant for her research focused on improving drug treatments for tuberculosis.

Aldridge’s research addresses a major obstacle in controlling tuberculosis, which is the lengthy multi-drug therapy currently required to effectively cure the disease. Due to the prolonged treatment, adherence to the drug therapy can be difficult. In addition, when these drugs are misused or mismanaged, multi-drug resistance can develop. To improve health outcomes for patients, and reduce the emergence of drug-resistant strains of the disease, she hopes to shorten and simplify treatments for tuberculosis. The Aldridge lab includes a multidisciplinary team of researchers who combine molecular approaches with mathematical modeling to study the bacterium that causes tuberculosis.


Kaplan’s Team On Board for Continued Regenerative Medicine Research

Today, the Institute for Regenerative Medicine at Wake Forest University School of Medicine announced that the second phase of the Armed Forces Institute of Regenerative Medicine (AFIRM) project will move ahead with involvement from researchers on Stern Family Professor David Kaplan’s biomedical engineering team. The five-year, $75 million federally funded project focuses on applying regenerative medicine to battlefield injuries.

Anthony Atala, M.D., director of the Wake Forest Institute for Regenerative Medicine, is the lead investigator for AFIRM-II. He will direct a consortium of more than 30 academic institutions, including Tufts School of Engineering, and industry partners.

In the first phase of AFIRM, which began in 2008, Kaplan’s group looked at soft tissue reconstruction and peripheral nerve repair research. During this phase, Kaplan will focus on muscle regeneration.


Silkworms Stitch Together Engineering and Art

Professor Fiorenzo Omenetto in the Department of Biomedical Engineering collaborated with the Mediated Matter Research Group at the MIT Media Lab to produce the Silk Pavilion–a stunning geometric structure constructed by silkworms and guided by engineers.

The Silk Pavilion explores the relationship between digital and biological fabrication on product and architectural scales.

SILK PAVILION from Mediated Matter Group on Vimeo.

The primary structure was created of 26 polygonal panels made of silk threads laid down by a CNC (Computer-Numerically Controlled) machine. Inspired by the silkworm’s ability to generate a 3D cocoon out of a single multi-property silk thread (1km in length), the overall geometry of the pavilion was created using an algorithm that assigns a single continuous thread across patches providing various degrees of density.

Overall density variation was informed by the silkworm itself deployed as a biological “printer” in the creation of a secondary structure. A swarm of 6,500 silkworms was positioned at the bottom rim of the scaffold spinning flat non-woven silk patches as they locally reinforced the gaps across CNC-deposited silk fibers. Following their pupation stage the silkworms were removed. Resulting moths can produce 1.5 million eggs with the potential of constructing up to 250 additional pavilions.

Affected by spatial and environmental conditions including geometrical density as well as variation in natural light and heat, the silkworms were found to migrate to darker and denser areas. Desired light effects informed variations in material organization across the surface area of the structure. A season-specific sun path diagram mapping solar trajectories in space dictated the location, size and density of apertures within the structure in order to lock-in rays of natural light entering the pavilion from South and East elevations. The central oculus is located against the East elevation and may be used as a sun-clock.

Parallel basic research explored the use of silkworms as entities that can “compute” material organization based on external performance criteria. Specifically, we explored the formation of non-woven fiber structures generated by the silkworms as a computational schema for determining shape and material optimization of fiber-based surface structures.

Research and Design by the Mediated Matter Research Group at the MIT Media Lab in collaboration with Prof. Fiorenzo Omenetto and Dr. James Weaver (WYSS Institute, Harvard University). Mediated Matter researchers include Markus Kayser, Jared Laucks, Carlos David Gonzalez Uribe, Jorge Duro-Royo and Neri Oxman (Director).


Trimmer to Head New Journal on Soft Material Robotics

Barry Trimmer heads up a new journal, SoRo, focusing on soft material robotics.

Barry Trimmer heads up a new journal, SoRo, focusing on soft material robotics.

Barry Trimmer, Henry Bromfield Pearson Professor of Natural Sciences, adjunct professor of biomedical engineering, and Director of the Neuromechanics and Biomimetic Devices Laboratory, has been named editor-in-chief of a new journal dedicated to soft material robotics.

The new journal, called Soft Robotics (SoRo), will be published quarterly online with Open Access options and in print. SoRo combines advances in biomedical engineering, biomechanics, mathematical modeling, biopolymer chemistry, computer science, and tissue engineering to present new approaches to the creation of robotic technology and devices that can undergo dramatic changes in shape and size in order to adapt to various environments.

“The next frontier in robotics is to make machines that can assist us in everyday activities, at home, in the office, in hospitals, and even in natural environments,” says Trimmer director of the Soft Material Robotics | IGERT doctoral program at Tufts. “Soft Robotics provides a forum, for the first time, for scientists and engineers across diverse fields to work together to build the next generation of interactive robots. This journal provides biologists, engineers, materials specialists, and computer scientists a common meeting place, and we are very excited about this new forum.”

This article first appeared as a press release from Mary Ann Liebert, Inc. publishers, July 18, 2013.


Omenetto’s Research Provides Basis for Bionic Ears

Last year, a research effort led by Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton, Naveen Verma, an assistant professor of electrical engineering, and Professor Fiorenzo Omenetto of Tufts University, resulted in the development of a “tattoo” made up of a biological sensor and antenna that can be affixed to the surface of a tooth.

Scientists used 3-D printing to merge tissue and an antenna capable of receiving radio signals. (Credit: Frank Wojciechows

Scientists used 3-D printing to merge tissue and an antenna capable of receiving radio signals. (Credit: Frank Wojciechowski)

A new project, however, is the team’s first effort to create a fully functional organ: one that not only replicates a human ability, but extends it using embedded electronics.

“The design and implementation of bionic organs and devices that enhance human capabilities, known as cybernetics, has been an area of increasing scientific interest,” the researchers wrote in the article which appears in the scholarly journal Nano Letters. “This field has the potential to generate customized replacement parts for the human body, or even create organs containing capabilities beyond what human biology ordinarily provides.

This story appeared as a press release on EurekAlert, May 1, 2013.

 


Levin Lab Looks at Cell Voltage as Cancer Treatment

Professor Michael Levin, in the Department of Biology in the School of Arts and Sciences, and doctoral student Brook Chernet, are exploring how changes in cell voltage affect cellular development and, potentially, cancer treatment.

“We have to get away from the idea that it’s always physical matter that’s at the root of the problem – that there’s a damaged gene, or a chemical toxin,” says Levin, also an adjunct biomedical engineering professor. “It’s not always that.”

Levin and Chernet injected messenger RNA that encodes human oncogenes – genes that can transform normal cells into tumor cells – into tadpoles. Next, they soaked the frog larvae in fluorescent dye. This dye was voltage-sensitive, fluorescing more brightly when the cell polarization was greater.

In Michael Levin's lab, fluorescence is used to highlight cellular development in tadpoles.  (Credit: Brook Chernet)

In Michael Levin’s lab, fluorescence is used to highlight cellular development in tadpoles. (Credit: Brook Chernet)

Levin and Chernet separated out tadpoles exhibiting a dark patch of low fluorescence. They found that, over several days, such patches of lowered polarization nearly always developed into tumors, confirming the link between cell polarization and cancer.

Cells become polarized when there is an imbalance of the positive and negative ions that flow in and out of cells through channels in cell membranes. But polarization itself regulates the operation of so-called transporter proteins, which pump signalling molecules through the channels. Through their experiments, Levin and Chernet have found that a lowered polarization inhibits the function of a transporter protein that draws in the signalling molecule butyrate, which, through various enzymes, controls the expression of growth genes. With less butyrate in the cell, these genes are free to instigate abnormally high, cancerous growth.

As a next step, Levin and Chernet split their oncogene-injected tadpoles into two groups. One group received injections of messenger RNA that encodes proteins for new ion channels. The new ion channels drew more negative ions into the tadpole cells, thereby increasing the cells’ polarization. The injected group of tadpoles did not develop nearly so many tumors as the untreated group, demonstrating that polarization is indeed a way to reign in tumors – at least in tadpoles (Dis. Model Mech. 6 595). To pave the way for clinical trials, Levin and Chernet will now have to show that the same results can be found in mammals.

This article was originally published in the July 2013 issue of Physics World magazine, a special issue on the physics of cancer. For a limited time only, you can download a PDF of the issue free of charge from physicsworld.com.

 

 


Xu Named Pew Scholar in Biomedical Sciences

 Assistant professor of biomedical engineering Qiaobing Xu was recently named a Pew scholar for his work in nanotechnology related to tissue regeneration. (Credit: Kelvin Ma/Tufts University)

Assistant Professor of biomedical engineering Qiaobing Xu was named a Pew scholar for his work in nanotechnology related to tissue regeneration. (Credit: Kelvin Ma/Tufts University)

Assistant Professor Qiaobing Xu in the Department of Biomedical Engineering was named a Pew Scholar in Biomedical Sciences by the Pew Charitable Trusts. The highly competitive program, whose past winners have included Nobel Prize winners, MacArthur Fellows and recipients of the Albert Lasker Basic Medical Research Award, identifies talented researchers in medicine or biomedical sciences. Xu’s work focuses on nanotechnology for biomedical uses. He will receive $240,000 over four years to advance his research.

Xu’s research delves into tissue engineering and nanomedicine. His lab has pioneered the use of nature-derived nanostructured tissue—decellularized tendon— as a source of biomaterials and works to engineer these materials through a combination of tissue sectioning, multilayer stacking and rolling into structures with innovative biomedical functions.

This press release first appeared in Tufts Now, June 13, 2013.


Strongest Spider Silk Produced in Bacteria

Engineering students from Northeastern University worked with Professor and Chair David Kaplan in the Department of Biomedical Engineering to engineer a theoretical method for producing spider silk in bacterial cells at currently unmatched concentrations. Silk from the Caerostris darwini spider of Madagascar is more robust than any material at ten times the toughness of Kevlar.

Credit: Thinkstock

The team’s project won first place at this year’s New Eng­land Bio­engi­neering Con­fer­ence.

Read more about the technology in Kaplan’s paper in Proceedings of the National Academy of Sciences (PNAS).

Xiao-Xia Xia, Zhi-Gang Qian, Chang Seok Ki, Young Hwan Park, David L. Kaplan, and Sang Yup Lee. Native-sized recombinant spider silk protein produced in metabolically engineered Escherichia coli results in a strong fiber. PNAS, 2010; DOI: 10.1073/pnas.1003366107

This story by Angela Herring first appeared in news@Northeastern on May 10, 2013.