nano applications / nano medicine / nanofabrication

Scientists roll up and inject brain implants using a syringe (just like a drug)!

The day has come! Scientists now can just inject the electronics in to living things (and the subject lives) just like any other drug. Amazingly, they picked the most complex place to begin with; brain. The work was truly groundbreaking in its field and described in Nature Nanotechnology journal two months back. The research was a collaboration between Harvard University, USA and National center for Nanoscience and Technology, China and who discovered a novel type of flexible electronic device that can be directly injected to brain through a regular medical syringe.

Injecting hope

Slotting in a circuit in to the brain may not seem like a good idea. But being able to do this without a major brain surgery that involves opening up the skull and inserting electrodes, presents a great achievement. This is especially true for people who are suffering from brain related neurodegenerative diseases like Parkinson’s and Alzheimer’s disease and other brain disorders like schizophrenia and Dystonia. Traditional therapeutic approach for these brain diseases includes deep brain stimulation or electrical brain stimulation, which is a FDA approved technique. It is carried out by implanting electrodes in to strategic regions of the brain to stimulate or to produce electrical pulses to normalize the abnormal ones. These devices also referred to as brain pacemakers due to its ability to perform electric brain simulation using an electric pulse, which presents larger portion of current implanted electronics used in therapeutic applications.

One other application of brain implants is as an interface between brain and a computer. This can greatly help people who are disabled and suffering from conditions like paralysis. Such an interface would allow direct control of a device such as a smart wheelchair or a prosthetic limb.

Understanding the secrets of brain and how it works is a big research area in modern science. Deciphering the information hidden in the brain waves can one day enable telepathic communication or in near terms, disable people to communicate through a computer. Infect, brain implants, including circuits and electronics presents a huge step towards transhumanism; a movement towards greatly enhanced human intellectual, physical, and psychological capacity building.

Jumping the hurdle

Current brain implant systems are mostly electrodes with no circuits and electronics and mainly used for extraction of electrical signals that neurons produce. However, present systems provide a poor interface between the brain tissues and electrodes. They are large and rigid. These rigid structures often cause tissue damage triggering an immune response which can render these devices less useful in long term use. They also lose their ability to optimally function with the time due to mechanical mismatch and repositioning with the time.

Although years of research has led to lot of progress in implantable devices in terms of flexibility and biocompatibility, poor tissue-electrode interface and requirement of complex surgical procedures remained as a major hurdle to cross. However, an ingenious device made possible by nanotechnology could finally break this limitation. This new brain implant is a mesh device, with features in the size range of the biological cells. This could make the device more biocompatible and provide a better interface with biological tissues. Mesh circuit in this new device is highly flexible, at least several orders compared to the conventional electronic implants.

mesh electrode,construction of the brain implant, mesh electrode

Team used well established photolithographic techniques to fabricate the brain implant. The device is fabricated mainly with nanoscale wires made of metals and nanocoatings of polymers to insulate them. Scientists can also built in sensors, electronic devices like transistors and receiver pins to the device. All this is fabricated in a mesh of centimeter and a half in width.

Cell interface between the brain implant and nujrons

The most outstanding feature of the device is its ability to be rolled in to a size that can fit the space in a hypodermic needle whose diameters is only few hundreds of micrometers. This allows scientists to inject the device directly in to the brain, typically near to a ventricular cavity where it unfolds to 80% of its original size conforming to the three dimensional environment around it. The biocompatible nanocoating allows the growth of the brain cells and neurons on the mesh electrode making a near perfect interface between the two.

unravelling of the mesh electrode brain implant

The research paper reports how scientists used a syringe to inject the mesh electrode directly in to brains of live mice. They successfully gathered the brain signals including brain waves through the section of the implant that remained outside of the body. The team has gathered data using the brain implant for several months in live mice, without any signal degradation. The implant triggered very little immune response which is natural. The team aims to test the system on primates as the next step to test its effectively in long durations, before moving in to human trials.

Further reading

  1. Liu, Jia, Tian-Ming Fu, Zengguang Cheng, Guosong Hong, Tao Zhou, Lihua Jin, Madhavi Duvvuri et al. “Syringe-injectable electronics.” Nature nanotechnology(2015).

  2. Sun, Mingui, Marlin Mickle, Wei Liang, Qiang Liu, and Robert J. Sclabassi. “Data communication between brain implants and computer.” Neural Systems and Rehabilitation Engineering, IEEE Transactions on11, no. 2 (2003): 189-192.


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