Researchers at Mayo Clinic, Harvard Medical School and the Massachusetts Institute of Technology are developing a biomaterial that has potential to protect patients at high risk for bleeding in surgery.
The Nov. 16 cover article, “An Injectable Shear-Thinning Biomaterial for Endovascular Embolization,” in the journal Science Translational Medicine reports on a universal shear-thinning biomaterial that may provide an alternative for treating vascular bleeding.
Endovascular embolization is a minimally invasive procedure that treats abnormal blood vessels in the brain and other parts of the body beginning with a pinhole puncture in the femoral artery. This procedure is accomplished by inserting metallic coils through a catheter into a vessel, which induces clotting to prevent further bleeding.
For patients unable to form a clot within the coiled artery or patients on high doses of blood thinners for their mechanical valves or cardiac assist devices, coil embolization could lead to complications, such as breakthrough bleeding, according to the study.
Despite its improvement over open surgical procedures, rebleeding after coil embolization is common and can be life-threatening, states the study.
The study’s lead co-author Rahmi Oklu, M.D., Ph.D., a vascular interventional radiologist at Mayo Clinic’s Arizona campus, explains shear-thinning biomaterial offers many advantages over metallic coils, the current gold standard.
“Coils require your body’s ability to create a clot in order to create that occlusion. Our shear-thinning biomaterial, regardless of how anticoagulated the patient may be, will still create that occlusion,” says Dr. Oklu, who began researching the shear-thinning biomaterial three years ago while working at Massachusetts General Hospital, Harvard Medical School, in collaboration with his colleague, Ali Khademhosseini, Ph.D., of Brigham and Women’s Hospital in Boston.
Dr. Oklu says the shear-thinning biomaterial, which can be injected through an endovascular catheter, creates an impenetrable cast of the vessel, preventing further bleeding. This shear-thinning biomaterial is easier to deliver and see on a CT and on MRI, enabling physicians to better assess the outcomes of the procedure, says Dr. Oklu.
Research on the shear-thinning biomaterial continues at Mayo Clinic. The goal is to address unmet patient needs, including possible treatment of vascular malformations, varicose veins, aneurysms and traumatic vascular injuries, as well as a drug delivery device in cancer treatment.
Biocompatible fibers could use light to stimulate cells or sense signs of disease
Researchers from MIT and Harvard Medical School have developed a biocompatible and highly stretchable optical fiber made from hydrogel — an elastic, rubbery material composed mostly of water. The fiber, which is as bendable as a rope of licorice, may one day be implanted in the body to deliver therapeutic pulses of light or light up at the first sign of disease.
The researchers say the fiber may serve as a long-lasting implant that would bend and twist with the body without breaking down. The team has published its results online in the journal Advanced Materials.
Using light to activate cells, and particularly neurons in the brain, is a highly active field known as optogenetics, in which researchers deliver short pulses of light to targeted tissues using needle-like fibers, through which they shine light from an LED source.
“But the brain is like a bowl of Jell-O, whereas these fibers are like glass — very rigid, which can possibly damage brain tissues,” says Xuanhe Zhao, the Robert N. Noyce Career Development Associate Professor in MIT’s Department of Mechanical Engineering. “If these fibers could match the flexibility and softness of the brain, they could provide long-term more effective stimulation and therapy.”
Getting to the core of it
Zhao’s group at MIT, including graduate students Xinyue Liu and Hyunwoo Yuk, specializes in tuning the mechanical properties of hydrogels. The researchers have devised multiple recipes for making tough yet pliable hydrogels out of various biopolymers. The team has also come up with ways to bond hydrogels with various surfaces such as metallic sensors and LEDs, to create stretchable electronics.
The researchers only thought to explore hydrogel’s use in optical fibers after conversations with the bio-optics group at Harvard Medical School, led by Associate Professor Seok-Hyun (Andy) Yun. Yun’s group had previously fabricated an optical fiber from hydrogel material that successfully transmitted light through the fiber. However, the material broke apart when bent or slightly stretched. Zhao’s hydrogels, in contrast, could stretch and bend like taffy. The two groups joined efforts and looked for ways to incorporate Zhao’s hydrogel into Yun’s optical fiber design.
Yun’s design consists of a core material encased in an outer cladding. To transmit the maximum amount of light through the core of the fiber, the core and the cladding should be made of materials with very different refractive indices, or degrees to which they can bend light.
“If these two things are too similar, whatever light source flows through the fiber will just fade away,” Yuk explains. “In optical fibers, people want to have a much higher refractive index in the core, versus cladding, so that when light goes through the core, it bounces off the interface of the cladding and stays within the core.”
Happily, they found that Zhao’s hydrogel material was highly transparent and possessed a refractive index that was ideal as a core material. But when they tried to coat the hydrogel with a cladding polymer solution, the two materials tended to peel apart when the fiber was stretched or bent.
To bond the two materials together, the researchers added conjugation chemicals to the cladding solution, which, when coated over the hydrogel core, generated chemical links between the outer surfaces of both materials.
“It clicks together the carboxyl groups in the cladding, and the amine groups in the core material, like molecular-level glue,” Yuk says.
The researchers tested the optical fibers’ ability to propagate light by shining a laser through fibers of various lengths. Each fiber transmitted light without significant attenuation, or fading. They also found that fibers could be stretched over seven times their original length without breaking.
Now that they had developed a highly flexible and robust optical fiber, made from a hydrogel material that was also biocompatible, the researchers began to play with the fiber’s optical properties, to see if they could design a fiber that could sense when and where it was being stretched.
They first loaded a fiber with red, green, and blue organic dyes, placed at specific spots along the fiber’s length. Next, they shone a laser through the fiber and stretched, for instance, the red region. They measured the spectrum of light that made it all the way through the fiber, and noted the intensity of the red light. They reasoned that this intensity relates directly to the amount of light absorbed by the red dye, as a result of that region being stretched.
In other words, by measuring the amount of light at the far end of the fiber, the researchers can quantitatively determine where and by how much a fiber was stretched.
“When you stretch a certain portion of the fiber, the dimensions of that part of the fiber changes, along with the amount of light that region absorbs and scatters, so in this way, the fiber can serve as a sensor of strain,” Liu explains.
“This is like a multistrain sensor through a single fiber,” Yuk adds. “So it can be an implantable or wearable strain gauge.”
The researchers imagine that such stretchable, strain-sensing optical fibers could be implanted or fitted along the length of a patient’s arm or leg, to monitor for signs of improving mobility.
Zhao envisions the fibers may also serve as sensors, lighting up in response to signs of disease.
“We may be able to use optical fibers for long-term diagnostics, to optically monitor tumors or inflammation,” he says. “The applications can be impactful.”
“Hydrogel fibers are very interesting and provide a compelling direction for embedding light within the human body,” says Fiorenzo Omenetto, a professor of biological engineering at Tufts University, who was not involved in the work. “These efforts in optimizing and managing the physical and mechanical properties of fibers are necessary and important next steps that will enable practical applications of medical relevance.”
The eye’s lacrimal gland is small but mighty. This gland produces moisture needed to heal eye injuries and clear out harmful dust, bacteria and other invaders.
If the lacrimal gland is injured or damaged by aging, pollution or even certain pharmaceutical drugs, a person can experience a debilitating condition called aqueous deficiency dry eye (ADDE)—sometimes called “painful blindness.”
Now a new study in animal models, led by scientists at The Scripps Research Institute (TSRI), suggests that lacrimal glands can be repaired by injecting a kind of regenerative “progenitor” cell.
“This is the first step in developing future therapies for the lacrimal gland,” said TSRI biologist Helen Makarenkova, who led the study.
The findings were published this week in the online Early Edition of the journal Stem Cells Translational Medicine.
Up for the Challenge
If injured, a healthy lacrimal gland naturally regenerates itself in about seven days. When diseased and chronically inflamed, however, regeneration stops—and scientists are not sure why.
In the new study, Makarenkova and her colleagues looked at whether they could kick start regeneration by injecting progenitor cells into the lobes that make up the lacrimal gland. Progenitor cells are similar to stem cells in their ability to differentiate into different kinds of tissue. In this study, the researchers used progenitor cells that were poised to become epithelial tissue, a key component of the lacrimal gland.
The researchers knew they faced a major challenge: sorting and separating “sticky” epithelial cell progenitors without destroying them.
“We had to figure out how to dissociate the tissue into single cells without completely obliterating everything,” said Anastasia Gromova, the study’s first author, now a graduate student at the University of California, San Diego, who spearheaded the project while interning at TSRI during her undergraduate years.
The researchers solved this problem by developing markers to label the cells of interest and then testing different enzymes and other reagents to draw them out of tissues.
Restoring Eye Health
With these cells in hand, the researchers injected them into the lacrimal glands of mouse models of Sjogren’s syndrome, an autoimmune disease that results in ADDE, dry mouth and other symptoms. The team used only older, female mice because ADDE most commonly strikes that demographic in humans.
The treated mice showed a significant increase in tear production, indicating—for the first time—that epithelial cell progenitors could repair the lacrimal gland. Further tests suggested that epithelial cell progenitors helped by restoring the connection between cells called myoepithelial contractile cells and the lacrimal gland’s secretory cells, which produce tears.
The next step in this research will be to study how long the improvement in the lacrimal gland lasts after progenitor cell injections. Makarenkova said the eventual goal is to develop therapies to boost a patient’s own regenerative abilities.
In addition to Makarenkova and Gromova, authors of the study, “Lacrimal Gland Repair Using Progenitor Cells,” were Dmitry A. Voronov of TSRI, the Russian Academy of Sciences and the A.N. Belozersky Institute of Physico-Chemical Biology of the Lomonosov Moscow State University; Miya Yoshida and Suharika Thotakura of TSRI; Robyn Meech of Flinders University; and Darlene A. Dartt of the Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard Medical School.
Human and computer analyses together identify cancer with 99.5% accuracy
Pathologists have been largely diagnosing disease the same way for the past 100 years, by manually reviewing images under a microscope. But new work suggests that computers can help doctors improve accuracy and significantly change the way cancer and other diseases are diagnosed.
A research team from Beth Israel Deaconess Medical Center (BIDMC) and Harvard Medical School (HMS) recently developed artificial intelligence (AI) methods aimed at training computers to interpret pathology images, with the long-term goal of building AI-powered systems to make pathologic diagnoses more accurate.
“Our AI method is based on deep learning, a machine-learning algorithm used for a range of applications including speech recognition and image recognition,” explained pathologist Andrew Beck, MD, PhD, Director of Bioinformatics at the Cancer Research Institute at Beth Israel Deaconess Medical Center (BIDMC) and an Associate Professor at Harvard Medical School. “This approach teaches machines to interpret the complex patterns and structure observed in real-life data by building multi-layer artificial neural networks, in a process which is thought to show similarities with the learning process that occurs in layers of neurons in the brain’s neocortex, the region where thinking occurs.”
The Beck lab’s approach was recently put to the test in a competition held at the annual meeting of the International Symposium of Biomedical Imaging (ISBI), which involved examining images of lymph nodes to decide whether or not they contained breast cancer. The research team of Beck and his lab’s post-doctoral fellows Dayong Wang, PhD and Humayun Irshad, PhD, and student Rishab Gargya, together with Aditya Khosla of the MIT Computer Science and Artificial Intelligence Laboratory, placed first in two separate categories, competing against private companies and academic research institutions from around the world. The research team today posted a technical report describing their approach to the arXiv.org repository, an open access archive of e-prints in physics, mathematics, computer science, quantitative biology, quantitative finance and statistics.
Harvard Medical School (HMS) is the graduate medical school of Harvard University.
It is located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts. It is currently ranked the #1 research medical school in the United States by U.S. News & World Report.
The school has a large and distinguished faculty to support its missions of education, research, and clinical care. These faculty hold appointments in the basic science departments on the HMS Quadrangle, and in the clinical departments located in multiple Harvard-affiliated hospitals and institutions in Boston. There are approximately 2,900 full- and part-time voting faculty members consisting of assistant, associate, and full professors, and over 5,000 full or part-time, non-voting instructors.
The Latest Updated Research News:
Harvard Medical School research articles from Innovation Toronto
- Artificial Intelligence Achieves Near-Human Performance in Diagnosing Breast Cancer – June 23, 2016
- Bionic leaf turns sunlight into liquid fuel at 10 times the efficiency of photosynthesis – June 3, 2016
- Finding Zika one paper disc at a time in 2 to 3 hours – May 7, 2016
- Biosensors on demand by designer proteins – February 14, 2016
- Diagnosing depression before it starts – January 27, 2016
- Microbiomes could hold keys to improving life as we know it – October 30, 2015
- Researchers Develop Techniques to Bypass Blood-Brain Barrier, Deliver Drugs to Brain and Nervous System – October 24, 2015
- Synthetic biology needs robust safety mechanisms before real world application – September 20, 2015
- Scientists Develop Antibody to Treat Traumatic Brain Injury and Prevent Long-Term Neurodegeneration – July 17, 2015
- Revolutionary £16 blood test reveals every virus you’ve ever had – June 6, 2015
- Medical millirobots offer hope for less-invasive surgeries – May 31, 2015
- New Biosensing Platform Could Quickly and Accurately Diagnose Disease and Monitor Treatment Remotely – April 4, 2015
- USC scientists open door for asthma cure – March 11, 2015
- A Breakthrough in Artificial Photosynthesis – February 11, 2015
- ‘Smart’ Bandage Emits Phosphorescent Glow for Healing Below – October 3, 2014
- Revisiting LSD as a Treatment for Alcoholism – August 24, 2014
- USC Stem Cell researcher targets the “seeds” of breast cancer metastasis – July 13, 2014
- ‘Heart disease-on-a-chip’ – May 12, 2014
- Promising results for Swedish cancer drug candidate
- Cross-Disciplinary Team From Harvard and Dana-Farber Brings Novel Therapeutic Cancer Vaccine to Human Clinical Trials
- High-octane bacteria could ease pain at the pump
- Reversing aging? Factor That Reverses Aging of Heart Discovered
- Oil for the Joints: Grinstaff Advances New Osteoarthritis Treatment
- Mass. Eye and Ear Researchers Regenerate Sensory Hair Cells, Restore Hearing to Noise-Damaged Ears
- Precisely engineering 3-D brain tissues
- Happiness Is The Ultimate Economic Indicator
- The New Generation of Microbe Hunters
- Cancer Testing? There’s an App for That
- New Device to Test Blood Can Spot Cancer Cells, HIV on the Fly
- Researchers Create Self-Assembling Nanodevices That Move and Change Shape on Demand
New system surpasses efficiency of photosynthesis
The days of drilling into the ground in the search for fuel may be numbered, because if Daniel Nocera has his way, it’ll just be a matter of looking for sunny skies.
Nocera, the Patterson Rockwood Professor of Energy at Harvard University, and Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, have co-created a system that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels.
The paper, whose lead authors include postdoctoral fellow Chong Liu and graduate student Brendan Colón, is described in a June 3 paper published in Science.
“This is a true artificial photosynthesis system,” Nocera said. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.”
While the study shows the system can be used to generate usable fuels, its potential doesn’t end there, said Silver, who is also a founding core member of the Wyss Institute at Harvard University.
A novel, inexpensive method for detecting the Zika virus could help slow spread of outbreak, and potentially other future pandemic diseases
An international, multi-institutional team of researchers led by synthetic biologist James Collins, Ph.D., at the Wyss Institute for Biologically Inspired Engineering at Harvard University, has developed a low-cost, rapid paper-based diagnostic system for strain-specific detection of the Zika virus, with the goal that it could soon be used in the field to screen blood, urine, or saliva samples.
“The growing global health crisis caused by the Zika virus propelled us to leverage novel technologies we have developed in the lab and use them to create a workflow that could diagnose a patient with Zika, in the field, within 2-3 hours,” said Collins, who is a Wyss Core Faculty member, and Termeer Professor of Medical Engineering & Science and Professor of Biological Engineering at the Massachusetts Institute of Technology (MIT)’s Department of Biological Engineering.
Building off previous work done at Harvard’s Wyss Institute by Collins and his team, along with collaborators from Massachusetts Institute of Technology (MIT), the Broad Institute of Harvard and MIT, Harvard Medical School (HMS), University of Toronto, Arizona State University (ASU), University of Wisconsin-Madison (UW-Madison), Boston University (BU), Cornell University, and Addgene, joined their efforts to quickly prototype the rapid diagnostic test and describe their methods in a study published online May 6 in the journal Cell, all within a matter of six weeks. Collins is the paper’s corresponding author.
Emerging innovation during the Ebola health crisis
In October 2014, Collins’ team developed a breakthrough method for embedding synthetic gene networks — which could be used as programmable diagnostics and sensors – on portable, small discs of ordinary paper.
Brain scans may identify children who are vulnerable to depression, before symptoms appear
A new brain imaging study from MIT and Harvard Medical School may lead to a screen that could identify children at high risk of developing depression later in life.
In the study, the researchers found distinctive brain differences in children known to be at high risk because of family history of depression. The finding suggests that this type of scan could be used to identify children whose risk was previously unknown, allowing them to undergo treatment before developing depression, says John Gabrieli, the Grover M. Hermann Professor in Health Sciences and Technology and a professor of brain and cognitive sciences at MIT.
Read more: Diagnosing depression before it starts