Summary: Researchers have created small, wireless devices that can fit around individual neurons, possibly assisting in the treatment of neurological conditions like multiple sclerosis.
These products, made from a gentle polymers, roll up tightly around cell structures when exposed to light, allowing exact dimension and modification of biological activity. As they’re battery-free and controlled noninvasively by light, hundreds of them could get deployed in the body together.
By acting as artificial myelin for axons that have been damaged, this innovative technique could recover neuron functionality. Integration circuits for nerve surveillance and treatments may be used in the future. The study suggests a novel approach to developing less restrictive neurological interface.
Important Facts:
- These cell-wearable tools are activated by lighting, making them battery-free.
- The devices cover around cerebral structures, offering chemical myelin benefits.
- Neuron repair and invasive neural modulation have potential applications.
Origin: MIT
Smart components, such as our heart rate or rest periods, interact with our body to assess and learn from internal procedures, such as ours.
Researchers at MIT have now created portable devices that could serve a similar purpose for personal cells inside the body.
These battery-free, subcellular-sized tools, made of a delicate polymer, are designed to gently wrap around different parts of cells, such as neurons and neurons, without damaging the cells, upon wireless steering with lighting.
They could be used to monitor or control a neuron’s electronic and physiological activity at a subcellular level by tightly wrapping synaptic processes.
The researchers believe that thousands of tiny, mobile devices could one day be injected and then actuated non-invasively with light because of how freely-floating and mobile they are.
By controlling how much light from outside the body was reflected off the cells, researchers could perfectly control how the wearables gently encircle them.
These gadgets could help reverse some cerebral degradation that occurs in conditions like multiple sclerosis by enfolding neurons that carry electrical impulses between cells and other organs. In the long run, the components could be combined with other components to create little circuits that can control and measure individual cells.
The AT&, T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, mind of the Nano-Cybernetic Biotrek Lab, and senior author of a report on this approach, says Deblina Sarkar, the senior writer of a report on this method.” The concept and platform technology we introduce these is like a founding stone.
Sarkar is joined on the paper by lead author Marta J. I. Airaghi Leccardi, a former MIT postdoc who is now a Novartis Innovation Fellow, Benoît X. E. Desbiolles, an MIT postdoc, Anna Y. Haddad ‘ 23, who was an MIT undergraduate researcher during the work, and MIT graduate students Baju C. Joy and Chen Song.
The research , appears today in , Nature Communications Chemistry.
Snugly wrapping cells
Due to the complexity of brain cells, it is extremely challenging to create a bioelectronic implant that can closely resemble neurons or neuronal processes. For instance, axons are slender, tail-like structures that attach to the cell body of neurons, and their length and curvature vary widely.
Axons and other cellular components are fragile at the same time, so any device that interacts with them must be soft enough to make good contact without causing any harm to them.
To overcome these challenges, the MIT researchers developed thin-film devices from a soft polymer called azobenzene, that do n’t damage cells they enfold.
Due to a material transformation, thin sheets of azobenzene will roll when exposed to light, enabling them to wrap around cells. By altering the light’s intensity, polarization, and device shape, researchers can precisely control the direction and diameter of the rolling.
The thin films can create tiny microtubes with a diameter less than a micrometer. This enables them to gently, but snugly, wrap around highly curved axons and dendrites.
” The diameter of the rolling can be very carefully controlled. You can stop if you want to go to a certain dimension by changing the light energy accordingly, says Sarkar.
The researchers used a number of different fabrication methods to find a process that was scalable and did n’t call for the use of a semiconductor clean room.
Making microscopic wearables
A water-soluble material is first deposited onto a sacrificial layer, which is then submerged in a drop of azobenzene. The researchers then adhere thousands of tiny devices to the sacrificial layer by stamping onto the drop of polymer. They can make complex structures, ranging from rectangles to flower shapes, thanks to stamping.
After the final batch of baking, the process uses etching to scrape any remaining material between the various devices. All solvents are completely evaporated. After the sacrificial layer is completely removed, thousands of microscopic devices are left floating in the water, free of charge.
Once they have a solution for their free-floating solutions, they wirelessly activate the solutions with light to cause them to roll. They discovered that free-floating structures can keep their shape for days after the illumination stops.
The entire process was tested by the researchers to make sure it was biocompatible.
They tested the devices on rat neurons after discovering they could tightly wrap around even highly curved axons and dendrites without causing damage.
The devices must be soft and able to conform to these complex structures in order to have intimate interfaces with these cells. That’s the issue we faced in this endeavor. We were the first to demonstrate that azobenzene can even encircle living cells,” she claims.
One of the biggest difficulties they encountered was creating a scalable fabrication procedure that could be carried out in a filthy environment. Additionally, they iterated on the device’s ideal thickness because making them too thick can cause cracking when rolling.
One obvious use for azobenzene as synthetic myelin for damaged axons is because it acts as an insulator. An insulating layer that covers axons allows electrical impulses to flow freely between neurons.
In non-myelinating diseases like multiple sclerosis, neurons lose some insulating myelin sheets. There is no biological way to regenerate them. The wearables may assist in recovering MS patients ‘ neuronal function by acting as synthetic myelin.
The researchers also demonstrated how to combine the devices with optoelectrical stimulators.
Moreover, atomically thin materials can be patterned on top of the devices, which can still roll to form microtubes without breaking. This opens up possibilities for incorporating sensors and circuits into the components.
One could also stimulate subcellular regions with very little energy because they have such a strong connection with cells. This might help a researcher or physician regulate the electrical activity of neurons in order to treat brain diseases.
” It is exciting to show how a cell and an artificial device interact at an unprecedented level. We have shown that this technology is possible”, Sarkar says.
The researchers want to try functionalizing the device surfaces with molecules that would allow them to target particular cell types or subcellular regions in addition to these applications.
This work represents a promising development of novel symbiotic neural interfaces that control the individual axons and synapses.
” When integrated with nanoscale 1- and 2D conductive nanomaterials, these light-responsive azobenzene sheets could become a versatile platform to sense and deliver different types of signals ( i. e., electrical, optical, thermal, etc. ) minimally or noninvasively to neurons and other cell types.
” Although preliminary, the cytocompatibility data reported in this work is also very promising for future use , in vivo“, says Flavia Vitale, associate professor of neurology, bioengineering, and physical medicine and rehabilitation at the University of Pennsylvania, who was not involved with this work.
The Swiss National Science Foundation and the American National Institutes of Health Brain Initiative provided funding for the study.
About this news from neurotech research
Author: Adam Zewe
Source: MIT
Contact: Adam Zewe – MIT
Image: The image is credited to Neuroscience News
Original Research: Open access.
Deblina Sarkar and colleagues ‘” Subcellular neuronal structures are wrapped in light-induced thin films made of azobenzene polymer..” Nature Communications Chemistry
Abstract
Subcellular neuronal structures are wrapped in light-induced thin films made of azobenzene polymer.
Neurons are essential cells composing our nervous system and orchestrating our body, thoughts, and emotions. Recent research efforts have focused on studying the single-cell properties as an individual complex system in addition to their collective structure and functions.
Nanoscale technology has the power to solve puzzles in neuroscience and support the neuron by examining and influencing various aspects of the cell.
We could envision a thousand times smaller interface to conform to subcellular regions of the neurons as wearable devices interact with various parts of our bodies for unprecedented contact, probing, and control.
However, it is important to create an interface that can bend into subcellular structures to accommodate their extreme curvatures.
We present a platform that can even be used to control small neuronal processes, which is a solution to this problem.
To accomplish this, we created a wireless platform made of an azobenzene polymer that has a sub-micrometer radius of curvature and undergoes on-demand light-induced folding.
We demonstrate that these platforms can be created with an adjustable form factor, micro-injected into neuronal cultures, and delicately wrapped in various neuronal processes ‘ morphologies in vitro to create seamless biointerfaces with increased coupling with the cell membrane. No adverse effects were observed when the platforms came into contact with the neurons during our in vitro tests.
Additionally, for future functionality, nanoparticles or optoelectronic materials could be blended with the azobenzene polymer, and 2D materials on the platform surface could be safely folded to the high curvatures without mechanical failure, as per our calculations.
Ultimately, this technology could lay the foundation for future integration of wirelessly actuated materials within or on its platform for neuromodulation, recording, and neuroprotection at the subcellular level.
