Lifelike artificial lung does away with pure oxygen

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Summary: Researchers in Cleveland, Ohio have built an artificial lung that reaches functional parity with a human lung. The device uses oxygen sourced from the air rather than pure oxygen as current man-made lungs require.

Large mechanical ventilators in which blood from the patient is circulated through a machine to oxygenate it could one day be a thing of the past.

Researchers in Cleveland, Ohio, have built an artificial lung that reaches functional parity with a human lung. The device uses oxygen sourced from the air rather than pure oxygen as current man-made lungs require.

The artificial lung is a major step toward creating an easily portable and implantable artificial lung, said Joe Potkay, a research assistant professor in electrical engineering and computer science at Case Western Reserve University.

Potkay and his team fashioned microfluidic channels from an organic silicon polymer (PDMS) and created ever smaller channels until the rubber tubes measured less than one-fourth the diameter of human hair, similar to the arteries and capillaries in a real lung. They added blood and air flow outlets and inlets and coated all the channels in a gas exchange membrane.

By following the design of the natural lung and making the parts on the same scale, the researchers were able to create a very large surface-area-to-volume ratio and shrink the distances for gas diffusion compared to the current state of the art.

Tests using pig blood show oxygen exchange efficiency is three to five times better, which enables them to use plain air instead of pure oxygen as the ventilating gas. Current artificial lung systems require heavy tanks and can only be used on patients at rest due to their inefficient oxygen exchange.

“Based on current device performance, we estimate that a unit that could be used in humans would be about 6 inches by 6 inches by 4 inches tall, or about the volume of the human lung. In addition, the device could be driven by the heart and would not require a mechanical pump,” Potkay said.

Not envisioned as a permanent transplant, the device would buy patients time while their own diseased lungs healed, or could act as a bridge while awaiting a lung transplant –- a wait that lasts, on average, more than a year.

Next for the team is to develop a coating to prevent clogging in the narrow artificial capillaries, and eventually, create a durable artificial lung large enough to test in rodent models of lung disease.

Within a decade, Potkay and his co-workers expects to have human-scale artificial lungs in use in clinical trials.

Potkay is the lead author of the paper describing the device and research, in the journal “Lab on a Chip.”

Christopher Jablonski is a freelance technology writer.

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An artificial 'super skin' for androids

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Summary: Stanford researchers have developed a stretchable, transparent skin-like sensor that could have applications in prosthetic limbs, robotics, and touch displays.

Credit: Steve Fyffe, Stanford News Service

The wrinkle-smoothing wonder of Botox could some day be a thing of the past.

Stanford researchers have built a new transparent skin-like sensor that can stretch out to more than twice its normal length in any direction and bounce back to its original shape.

The sensor uses a transparent film of single-walled carbon nanotubes that are bent to act as tiny springs. The springs help the sensor to accurately measure almost any force applied on it–from a firm pinch to thousands of pounds.

“This sensor can register pressure ranging from a firm pinch between your thumb and forefinger to twice the pressure exerted by an elephant standing on one foot,” said Darren Lipomi, a postdoctoral researcher in Bao’s lab, who is part of the research team. “None of it causes any permanent deformation,” he added.

According to Lipomi and his team, the sensor could be used in making touch-sensitive prosthetic limbs or robots, for various medical applications such as pressure-sensitive bandages or in touch screens on computers.

Key to the skin-like sensor are the carbon “nano springs.” They are airbrushed onto a thin layer of silicone to form a transparent film of randomly oriented little clumps the researchers like to describe as “conductive spaghetti.”

When the silicone is stretched, some of the clumps get pulled into alignment in the direction of the stretching. When released, the sensor rebounds back to its original dimensions while the nanotubes buckle and form little nanostructures that look like springs.

Stretching the sensor in the perpendicular direction yields additional clumps that transform into nano springs when released. Afterwards, stretched or un-stretched, the sensor maintains its total rebounding and conductivity properties.

The artificial skin is built using two layers of the nanotube-coated silicone, oriented so that the coatings are face-to-face, with a layer of easily deformable silicone in the middle. The silicone stores an electrical charge, much like a battery.

When pressure is exerted on the sensor, the silicone compresses, which alters the amount of electrical charge it can store. That change is detected by the two films of carbon nanotubes, which act like the positive and negative terminals on a typical automobile or flashlight battery. The change in electrical is charge is how the sensor transmits what it is “feeling.”

“One of the long term applications is to use a stretchable, conformable, skin-like device in artificial intelligence systems. If you have a robot or android like Data from Star Trek, its skin can potentially be made out of something like this,” said Lipomi in a video.

The research team published a paper describing the sensor in the latest issue of Nature Nanotechnology.

Related:

Meet ‘e-skin’: Artificial skin made from nanowires
A better wearable brain-computer interface
5 surprising uses for carbon nanotubes

Christopher Jablonski is a freelance technology writer.

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