In- vivo wireless neuropharmacology and optogenetics

Optogenetics, an approach in which light is used to control the activity of brain cells in animal models, relies on bulky and rigid probes surgically implanted into the brain and tethered to external devices. Current equipment can damage brain tissue, impede animals’ natural movements and behavior, and induce experimental artifacts.

Researchers developed a lightweight, wireless, injectable system of soft microscale LED probes encased in a coating of biocompatible polymers that simultaneously enables both optogenetic and pharmacologic experiments.

The system uses magnetic resonance coupling to wirelessly power the device from strategically placed external antennas. Refill ports on the sides of reservoirs allow drugs to be delivered in a consistent and controlled fashion.

Using the device, the authors wirelessly triggered the delivery of artificial cerebrospinal fluid and an opioid receptor agonist into the brains of mice following surgical implantation and stimulated GABAergic neurons in the brain’s ventral tegmental area during a behavioral test, demonstrating the device’s dual—pharmacologic and optogenetic—use.

Additional tests revealed that optogenetically induced animal movement can be pharmacologically blocked using the same device, indicating integrated function. The authors note that the 100-µm-thin, soft microfluidic probes circumvent the tissue inflammation and damage tied to stainless steel probes, and the design and manufacturing process are easily scalable in academic laboratories.

According to the authors, the optofluidic device could vastly enhance researchers’ ability to conduct sophisticated experiments in neuroscience.