Posts tagged 3d printing
Articles and news from the latest research reports.
Brain surgery through the cheek
For those most severely affected, treating epilepsy means drilling through the skull deep into the brain to destroy the small area where the seizures originate – invasive, dangerous and with a long recovery period.
Five years ago, a team of Vanderbilt engineers wondered: Is it possible to address epileptic seizures in a less invasive way? They decided it would be possible. Because the area of the brain involved is the hippocampus, which is located at the bottom of the brain, they could develop a robotic device that pokes through the cheek and enters the brain from underneath which avoids having to drill through the skull and is much closer to the target area.
To do so, however, meant developing a shape-memory alloy needle that can be precisely steered along a curving path and a robotic platform that can operate inside the powerful magnetic field created by an MRI scanner.
The engineers have developed a working prototype, which was unveiled in a live demonstration this week at the Fluid Power Innovation and Research Conference in Nashville by David Comber, the graduate student in mechanical engineering who did much of the design work.
The business end of the device is a 1.14 mm nickel-titanium needle that operates like a mechanical pencil, with concentric tubes, some of which are curved, that allow the tip to follow a curved path into the brain. (Unlike many common metals, nickel-titanium is compatible with MRIs). Using compressed air, a robotic platform controllably steers and advances the needle segments a millimeter at a time.
According to Comber, they have measured the accuracy of the system in the lab and found that it is better than 1.18 mm, which is considered sufficient for such an operation. In addition, the needle is inserted in tiny, millimeter steps so the surgeon can track its position by taking successive MRI scans.
According to Associate Professor of Mechanical Engineering Eric Barth, who headed the project, the next stage in the surgical robot’s development is testing it with cadavers. He estimates it could be in operating rooms within the next decade.
To come up with the design, the team began with capabilities that they already had.
“I’ve done a lot of work in my career on the control of pneumatic systems,” Barth said. “We knew we had this ability to have a robot in the MRI scanner, doing something in a way that other robots could not. Then we thought, ‘What can we do that would have the highest impact?’”
At the same time, Associate Professor of Mechanical Engineering Robert Webster had developed a system of steerable surgical needles. “The idea for this came about when Eric and I were talking in the hallway one day and we figured that his expertise in pneumatics was perfect for the MRI environment and could be combined with the steerable needles I’d been working on,” said Webster.
The engineers identified epilepsy surgery as an ideal, high-impact application through discussions with Associate Professor of Neurological Surgery Joseph Neimat. They learned that currently neuroscientists use the through-the-cheek approach to implant electrodes in the brain to track brain activity and identify the location where the epileptic fits originate. But the straight needles they use can’t reach the source region, so they must drill through the skull and insert the needle used to destroy the misbehaving neurons through the top of the head.
Comber and Barth shadowed Neimat through brain surgeries to understand how their device would work in practice.
“The systems we have now that let us introduce probes into the brain – they deal with straight lines and are only manually guided,” Neimat said. “To have a system with a curved needle and unlimited access would make surgeries minimally invasive. We could do a dramatic surgery with nothing more than a needle stick to the cheek.”
The engineers have designed the system so that much of it can be made using 3-D printing in order to keep the price low. This was achieved by collaborating with Jonathon Slightam and Vito Gervasi at the Milwaukee School of Engineering who specialize in novel applications for additive manufacturing.
Kids outfitted with new hands made on 3-D printers
Hopkins doctor joins big volunteer network using high-tech printers to fill need for little prosthetic hands
Chinese Doctors Use 3D-Printing in Pioneering Surgery to Replace Half of Man’s Skull
Surgeons at Xijing Hospital in Xi’an, Shaanxi province in Northwest China are using 3D-printing in a pioneering surgery to help rebuild the skull of a man who suffered brain damage in a construction accident.
Hu, a 46-year-old farmer, was overseeing construction to expand his home in Zhouzhi county last October when he was hit by a pile of wood and fell down three storeys.
Although he survived the fall, the left side of his skull was severely crushed and the shattered bone fragments needed to be removed, which has led to a depression of one side of his head.
Due to his injuries, Hu cannot see well out of his left eye, experiences double vision (diplopia) and is also unable to speak and write.
Accidentally cut your ear off? Just 3D print a new one
It’s way too late for Vincent van Gogh, but cutting off your ear is a much less impressive gesture now you can get a new one printed.
This week, researchers at Hangzhou Dianzi University in China unveiled their Regenovo 3D printer. Unlike more familiar 3D printers, which work with plastic or metal dust, Regenovo prints living tissue – such as these little ears.
The Hangzhou team aren’t the only ones 3D-printing spare parts for people. Earlier this year, a team at Cornell University in Ithaca, New York, also demonstrated an ear printer, and Organovo in San Diego, California, are on the way to building fresh human livers.
Meanwhile a team at Heriot-Watt University in Edinburgh, UK, has turned human embryonic stem cells into 3D-printer ink. Things are more advanced when it comes to making new bones, as a woman with a 3D-printed titanium jawbone could tell you.
Printable ‘bionic’ ear melds electronics and biology
Scientists at Princeton University used off-the-shelf printing tools to create a functional ear that can “hear” radio frequencies far beyond the range of normal human capability.
The researchers’ primary purpose was to explore an efficient and versatile means to merge electronics with tissue. The scientists used 3D printing of cells and nanoparticles followed by cell culture to combine a small coil antenna with cartilage, creating what they term a bionic ear.
"In general, there are mechanical and thermal challenges with interfacing electronic materials with biological materials," said Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton and the lead researcher. "Previously, researchers have suggested some strategies to tailor the electronics so that this merger is less awkward. That typically happens between a 2D sheet of electronics and a surface of the tissue. However, our work suggests a new approach — to build and grow the biology up with the electronics synergistically and in a 3D interwoven format."
McAlpine’s team has made several advances in recent years involving the use of small-scale medical sensors and antenna. Last year, a research effort led by McAlpine and Naveen Verma, an assistant professor of electrical engineering, and Fio 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.
This 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.”
Standard tissue engineering involves seeding types of cells, such as those that form ear cartilage, onto a scaffold of a polymer material called a hydrogel. However, the researchers said that this technique has problems replicating complicated three dimensional biological structures. Ear reconstruction “remains one of the most difficult problems in the field of plastic and reconstructive surgery,” they wrote.
To solve the problem, the team turned to a manufacturing approach called 3D printing. These printers use computer-assisted design to conceive of objects as arrays of thin slices. The printer then deposits layers of a variety of materials – ranging from plastic to cells – to build up a finished product. Proponents say additive manufacturing promises to revolutionize home industries by allowing small teams or individuals to create work that could previously only be done by factories.
Creating organs using 3D printers is a recent advance; several groups have reported using the technology for this purpose in the past few months. But this is the first time that researchers have demonstrated that 3D printing is a convenient strategy to interweave tissue with electronics.
The technique allowed the researchers to combine the antenna electronics with tissue within the highly complex topology of a human ear. The researchers used an ordinary 3D printer to combine a matrix of hydrogel and calf cells with silver nanoparticles that form an antenna. The calf cells later develop into cartilage.
Manu Mannoor, a graduate student in McAlpine’s lab and the paper’s lead author, said that additive manufacturing opens new ways to think about the integration of electronics with biological tissue and makes possible the creation of true bionic organs in form and function. He said that it may be possible to integrate sensors into a variety of biological tissues, for example, to monitor stress on a patient’s knee meniscus.
David Gracias, an associate professor at Johns Hopkins and co-author on the publication, said that bridging the divide between biology and electronics represents a formidable challenge that needs to be overcome to enable the creation of smart prostheses and implants.
"Biological structures are soft and squishy, composed mostly of water and organic molecules, while conventional electronic devices are hard and dry, composed mainly of metals, semiconductors and inorganic dielectrics," he said. "The differences in physical and chemical properties between these two material classes could not be any more pronounced."
The finished ear consists of a coiled antenna inside a cartilage structure. Two wires lead from the base of the ear and wind around a helical “cochlea” – the part of the ear that senses sound – which can connect to electrodes. Although McAlpine cautions that further work and extensive testing would need to be done before the technology could be used on a patient, he said the ear in principle could be used to restore or enhance human hearing. He said electrical signals produced by the ear could be connected to a patient’s nerve endings, similar to a hearing aid. The current system receives radio waves, but he said the research team plans to incorporate other materials, such as pressure-sensitive electronic sensors, to enable the ear to register acoustic sounds.
In addition to McAlpine, Verma, Mannoor and Gracias the research team includes: Winston Soboyejo, a professor of mechanical and aerospace engineering at Princeton; Karen Malatesta, a faculty fellow in molecular biology at Princeton; Yong Lin Kong, a graduate student in mechanical and aerospace engineering at Princeton; and Teena James, a graduate student in chemical and biomolecular engineering at Johns Hopkins.
The team also included Ziwen Jiang, a high school student at the Peddie School in Hightstown who participated as part of an outreach program for young researchers in McAlpine’s lab.
"Ziwen Jiang is one of the most spectacular high school students I have ever seen," McAlpine said. "We would not have been able to complete this project without him, particularly in his skill at mastering CAD designs of the bionic ears."
(Source: eurekalert.org)
These days, 3D printing is being used to mock up far more complex systems, says Arthur Olson, who founded the molecular graphics lab at the Scripps Research Institute in La Jolla, California, 30 years ago. These include molecular environments made up of thousands of interacting proteins, which would be onerous-to-impossible to make any other way. With 3D printers, Olson says, “anybody can make a custom model”. But not everybody does: many researchers lack easy access to a printer, aren’t aware of the option or can’t afford the printouts (which can cost $100 or more).