New material aids in neural stimulation using light

MXene flakes are effective for photostimulation. Credit: CMU College of Engineering
Targeting and stimulating neurons can bring many benefits, including improved understanding of brain function and treatment of neurological diseases. The current state-of the-art microelectrode arrays can stimulate neurons with high accuracy, but they lack cell type specificity, require invasive implantation that can cause tissue damage, and are not suitable for patients suffering from tremors. Tzahi Cohen Karni, Professor of Materials Science and Engineering and Biomedical Engineering has been researching new materials that allow remote photostimulation, which is the use of light to stimulate cell growth.

By sending and receiving electrical signals, cells can communicate with each other. A neuron in our brain, for example, has tiny pores called "ion channels" that allow ions to move inside the cell's membrane. Normal conditions dictate whether a cell sends an electrical signal to its neighbor. The fluxes of electrons across the membrane determine this. Researchers have demonstrated that pulses of light can be used to alter cell membrane properties and trigger an electrical signal that can control cell communication. Cohen-Karni's group aims to find materials that can control cell activity without causing distress. Multi-dimensional graphene (fuzzy or fuzzy graphene) was recognized as a potential candidate for cellular stimulation. However, they discovered that certain materials are difficult to make and can't efficiently transfer heat to light.

Cohen-Karni's current research was published by the American Chemical Society. It focused on MXenes flakes (transition metal carbides/nitrides) a unique 2-D nanomaterial discovered at Drexel University by Dr. Yury Ggotsi. MXenes are known for their outstanding mechanical properties, high electric conductivity, and excellent electrochemical properties. They also have a low cost of production.

Cohen-Karni's group measured the photothermal properties at one flake level, rather than studying the bulk properties of the material. The team spread flakes onto the dorsal root Ganglion (DRG) cells of the peripheral nervous system and lit them with short pulses light. Cohen-Karni was able to accurately measure the amount light needed to cause cellular change by studying the interaction between cells and the materials.

Cohen-Karni stated that the material that I am using in my lab doesn't require high energy pulses to stimulate. We found that the cell's electrophysiology was altered by shining short pulses light onto the DRG-MXene Interface.

What does this all mean for neurology's future? Remote photostimulation can be performed more efficiently with a better understanding of how to stimulate the brain and MXene production. Researchers could embed MXenes in artificial tissue designed to look like a brain and use light to control neural activity. This would further reveal the role of neurons during brain development. This material could eventually be used to treat neural function impairments, such as tremors, without the need for surgery.

The research was also carried out by Jane E. Hartung and Michael S. Gold, Materials Science and Engineering students Raghav Garg and Yingqaio Wu; Adam Goad and Dipna S. Patel, both from Drexel University; Flavia Vitale, University of Pennsylvania and Center for Neurotrauma, Neurodegeneration and Restoration.

Continue reading A remote control for neurons

More information: Yingqiao Zhang et al., Ti3C2TxMXene Flakes For Optical Control of Neuronal Electrical Activity. ACS Nano (2021). Information from the Journal: ACS Nano Yingqiao Zhang et al., Ti3C2TxMXene Flakes to Optical Control Neuronal Electrical Activity. (2021). DOI: 10.1021/acsnano.1c04431