AP Biology class blog for discussing current research in Biology

Tag: prosthetics

Printing More Than Just Pictures

3-D printing is an increasingly accessible technology that is bringing manufacturing into the home. Now these marvels of technology are being used in medicine. With children growing rapidly, expensive prosthetics are not an option for most families. Customized 3-D printed prosthetics are becoming more common and are helping out these families by making prosthetics less expensive.



3-D Printed Prosthetic Hand

Usually, 3-D printers only print hard material such as plastic and metal. This is very useful while creating bone replacements and customizable prosthetics, but is not ideal for printing organic tissue.

Bioprinting, or the printing of organic tissues, is a rising and feasible option in medical treatments. This advance would be a huge improvement to many practices such as medical testing and organ transplants. The ability to print organic tissue would eliminate the need for long donor list that many people wait on, but never receive an organ. With bioprinting doctors would be able to test their medicine on organic human tissue rather than animals. This all may sound like science fiction, however it is happening right now.

Carnegie Mellon recently bought a commercial 3-D printer for around 1,000 dollar and after some modifications began to print soft materials. Associate professor at Carnegie Mellon Adam Feinberg and others have developed a way to print soft materials in-expensively. The main problem with printing soft materials is the prints would collapse on the weight of itself. To prevent this the researchers at Carnegie Mellon created a process they now call FRESH (Freeform Reversible Embedding of Suspended Hydrogels). In this process the nozzle prints with a gel inside a petri dish filled with a supportive gel. Then they heat up the petri dish and the supportive gel melts away leaving the print.

As this technology is open source and inexpensive, hopefully many patients will be receiving their very own custom printed organs soon.


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A Step in the Right Direction: Advancement in Robotics Leading to Better Prosthetics

3356514403_e378d11342New strides in robotics technology have made it possible to create new types of prosthetics, which can function more naturally than a passive artificial leg. The H. Fort Flowers Professor of Mechanical Engineering at Vanderbilt University, Michael Goldfarb and his colleagues at the Vanderbilt’s Center for Intelligent Mechatronics are the leaders in lower-limb prosthetic research and have expressed their views on robotic prosthetics in an article in Science Translational Medicine‘s November issue. Goldfarb’s team developed the first robotic prosthesis, which included a powered knee and ankle joints. Their design became the first artificial leg controlled by thought after researchers at the Rehabilitation Institute of Chicago added a neural interface to it.

Technological advances, such as lithium-ion batteries, powerful brushless electric motors with rare-Earth magnets, and miniaturized sensors built into semiconductor chips, have allowed for new developments in robotic prosthetics. The electric motors, whose batteries store a single charge with enough power to last a full day, serve as the “muscles” of the prosthetic. The sensors function as its “nerves” like those in the peripheral nervous system by providing information like the angle between the thigh and lower leg and the force exerted on the bottom of the foot. The microprocessor acts as the central nervous system by providing coordination.

In order to recognize a user’s intent to do different activities, there must be and effective control system that provides some type of connection with the central nervous system. There are many different methods available, but it is still undecided which of these is best. The least invasive approach uses physical sensors to differentiate between the user’s intentions and his or her body language. Electromyography interface is a different approach that places electrodes within the user’s leg muscles. The most invasive techniques entail electrode implants inside the user’s peripheral nerves or directly into his or her brain.

Bionic legs seem to provide many possible advantages over passive artificial legs. Lower-limb prostheses with a powered knee and heel joints have demonstrated faster walking speed and decreased hip effort while using less energy. Robotic prosthesis could also decrease the rate of falls leading to hospitalization due to the leg’s natural movement, improved compensation for uneven ground, and ability to help users recover from stumbling. Despite their benefits, robotic legs face some issues before being launched in the United States. These challenges include approval from the United States Food and Drug Administration (FDA) and additional robotics training for clinicians prescribing these types of prostheses.

In spite of these challenges, this new development of robotic legs will surely prove beneficial to amputees across the country. Is there a more efficient way to help the public gain access to this type of technology? What can be learned from these new advances?

Photograph by Andy Polaine

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