Microfluidics + Carbon Nanotubes = Safer Brain Implantation

According to a report by Rices, researchers at Rice University have developed a new device that uses microfluidic technology to implant flexible conductive carbon nanotube fibers into the brain to help record neuronal activity and is expected to replace Traditional methods of implantation that may damage brain tissue.

Researchers at Rice University said that implant technology can improve the treatment of neuronal signals through electrodes and treat patients with epilepsy and other related diseases. Similarly, nanotube electrodes can help researchers and scientists identify the mechanisms behind cognitive processes that enable patients to see, hear, and control prosthetic limbs.

The device uses the force generated by the rapidly moving fluid to gently push the insulated flexible fibers into the brain tissue without deformation. This approach can replace traditional methods—using hard shuttles and biodegradable sheaths to introduce wires into the brain, which can cause damage to sensitive tissue.

In vivo experiments have shown that microfluidic devices are capable of forcing viscous fluids to flow around the fine fiber electrodes. The fast moving liquid pulls the fiber through a small hole leading to the brain tissue. Despite the high flexibility of the wire, once it enters the brain tissue, it remains completely straight.

One of the University's engineers, Project Coordinator Jacob Robinson said in a press release that "the electrode is like a cooked noodle, you try to put it in a bowl of jelly. It doesn't do anything." But when you put the noodles under water, the water will straighten the noodles. Even if the microfluids flow very fast, the wires will move slowly. Researchers point out that pulling something that is elastic is easier than pushing it.

Caleb Kemere, an electrical and computer engineer at Rice University, specializing in neuroscience, explains, "The most important thing is that we don't just pull the end or a certain position of the wire. We pull along the entire cross section of the electrode and distribute the tension evenly."

The holes through which the fibers are to be passed are three times the size of the fibers. However, it is still small and can only pass a small amount of fluid. The researchers said that fluid does not enter the brain tissue along the wire. The small gap between the microfluidic device and the brain tissue keeps the fiber in a defined path.

Robinson said, "We use this very short, unsupported length to penetrate into the brain and use the liquid flowing in the back end to maintain the hardness of the electrode and eventually penetrate it into the brain tissue."

Carbon nanotube fibers are capable of conducting electricity in all directions, but if they wish to communicate with neurons, they can only be conducted through their tips.

One of the researchers, Kemere, said, "We think insulation is a matter of course. But it's not easy to coat carbon nanotube fibers with a substance that keeps the integrity of the carbon nanotubes and prevents ions from entering from the side."

He developed a coating technology for carbon nanotube fibers that is kept between 15-30 microns wide and thinner than human hair. Robinson added, “Once we know the size of the fiber, we can make a device that matches its size. It turns out that we can make the diameter of the outlet channel twice or three times the diameter of the electrode, and there will be no A lot of fluid passes through."

Researchers hope they can further shrink the device with microfluidic technology to deliver multiple densely packed microelectrodes into the brain, making the implant safer and easier to embed.

The researchers published their findings in the Nano Letters, which was obtained from the Defense Advanced Research Project Agency, the Welch Foundation, and the United States. The Natio nal Science Foundation, the Air Force Office of Scientific Research, the Natio nal Institutes of Health, and the Citizens United for Research in Epilepsy Strong support for the Taking Flight bonus.