Electrical stimulation may take a backseat as light drives biohybrid actuators

Biohybrid actuators combine an artificial component with living cells to perform an action, creating a unique platform for soft robotics and sensors. In general, the devices use electrodes to inject an electrical current and stimulate cells. However, this requires wiring that makes changing the design cumbersome. The current can heat and damage the tissue, and the electrode can release toxic materials.

Vurro et al. described possible approaches for using light stimulation in biohybrid actuators, which can avoid many of these issues.

“In principle, with light, you can even probe inside the cell,” said author Guglielmo Lanzani. “This high specificity in space and time is difficult to achieve using electrodes, because typically, current spreads around, and you lose resolution.”

One approach, optogenetics, involves introducing exogeneous DNA through a virus into a cell. The DNA expresses a protein that is light sensitive, transforming the cell from its initial transparent state. While this technique allows for good control and selectivity, it requires strong light sources, and the gene therapy aspect is questionable for human use.

Alternatively, the team discussed nongenetic approaches that use infrared light to heat the water within cells or phototransducers.

“We introduce a transducer, sort of a nanophotovoltaic cell, that absorbs light in an efficient way and is coupled to the cell,” said Lanzani. “How this occurs depends on the material you are using, and it is still under investigation.”

The researchers aim to make a proof of concept of these ideas using cell lines, with the ultimate goal of creating a fully biocompatible device that can be used in robotics and injury rehabilitation applications.

Source: “A perspective on the use of light as a driving element for bio-hybrid actuation,” by V. Vurro, I. Venturino, and G. Lanzani, Applied Physics Letters (2022). The article can be accessed at https://doi.org/10.1063/5.0078411 .