Optogenetics moves toward clinical trials, treatments for diseases like Alzheimer’s

Optogenetics—the use of light to control living cells that have been genetically modified to be light-sensitive—could transform neuroscience if the technique could safely be applied to humans.

Optogenetics requires, first, “…genetic engineering of neurons to insert molecular switches to activate or switch off the cells,” as Stephani Sutherland puts it in Scientific American. The second step involves getting light to the sensitized cells.

This second step was the focus of research described by imec, KU Leuven, and Neuro-Electronics Research Flanders at last month’s IEEE International Electron Devices Meeting (IEDM 2015). The researchers presented a set of silicon neural probes that combine 12 monolithically integrated nanophotonic circuits, or optrodes, using a CMOS-compatible process. The probes enable optical stimulation and electronic detection of individual neurons. The probes can help pave the way to a greater understanding of the brain and towards the development of novel treatments for brain disorders such as Alzheimer’s, schizophrenia, autism, and epilepsy.

The researchers note that the brain is composed of many genetically and functionally distinct neuron types and that the new probes overcome the limitations of conventional probes, which cannot disambiguate recorded electrical signals with respect to their source.

Imec’s and KU Leuven’s probes are fully integrated implantable neural microsystems that can detect, process, and interpret neural data at a cellular scale. The systems feature a high density of electrodes and optrodes; the latter optically stimulate single neurons.

Be on the lookout for EE-Evaluation Engineering’s April print edition for more on the work of the imec and KU Leuven researchers. Meanwhile, Sutherland’s January 5 Scientific American article provides a concise overview of optogenetics’ history and promise. She quotes neuroscientist Robert Gereau of Washington University in Saint Louis as saying, “Optogenetics is not just a flash in the pan. It allows us to do experiments that were not doable before. This is a true game changer like few other techniques in science.” Gereau has tested on rodents fully implantable and wirelessly powered devices that sit atop peripheral nerves sensitized to light via the implanting of genes carried by viruses.

Sutherland cites startups that have formed to move the technology forward. For example, Circuit Therapeutics wants to begin clinical trials using optogenetics to treat chronic pain. And RetroSense Therapeutics plans to soon begin human trials of optogenetics for treating a genetic condition that causes blindness.

Sutherland concludes her article by again quoting Gereau: “I certainly believe there is therapeutic potential for optogenetics. Sutherland adds, “Within a decade, turning off pain neurons may differ little from flipping a light switch.”