Neurology Central

Self-tracking, wireless and implantable device may offer greater possibilities for optogenetic research

A newly engineered neuron-activating device intended for subcutaneous implantation and capable of wireless control in mice has been developed by researchers at Stanford University (CA, USA). The device, which was presented recently in Nature Methods, enables neural stimulation and modulation of nerves by a process known as optogenetics, in which nerves are engineered to contain light-sensitive proteins. The new technology may provide an opportunity to expand the scope of future investigations into neural modulation by allowing optogenetic studies of naturally behaving animals.

Optogenetics has been used to examine a range of topics within neurology, such as how to relieve tremors in Parkinson’s disease, exploring potential stroke treatments and studying the function of neurons that convey pain. Despite this, previously developed optogenetic devices have required larger head-mountable devices that employ fiber-optic cables and have prevented more complex movements associated with social functions from being analyzed due to the encumbering of both animal behavior and movement.

The newly engineered device weighs 20mg, has a surface area of 10mm3,causes minimal tissue heating of <1°C and contains a self-tracking system (range of 16 cm in diameter). Wireless powering of the device is enabled through a chamber that amplifies and stores radio frequency energy.

“This is a new way of delivering wireless power for optogenetics,” commented Ada Poon (Stanford University). “It’s much smaller and the mouse can move around during an experiment.” “I think other labs will be able to adapt this for their work.”

The miniature subcutaneous device may be used in the future to trigger nervous signals in muscles or other organs that were hitherto inaccessible to optogenetics. The authors attest that the new device offers greater possibilities for investigatory research into mental health, diseases of internal organs as well as movement disorders.

Sources: Stanford University press release; Montgomery KL, Yeh AJ, Ho JS et al. Wirelessly powered, fully internal optogenetics for brain, spinal and peripheral circuits in mice. Nat. Methods doi:10.1038/nmeth.3536 (2015) (Epub ahead of print); Ho JS, Tanabe Y, Iyer SM et al. Self-tracking energy transfer for neural stimulation in untethered mice. Phys. Rev. Appl. doi:10.1103/PhysRevApplied.4.024001 (2015) (Epub ahead of print).