Researchers, publishing in Nature Biomedical Engineering, believe the device can accelerate efforts to uncover brain diseases such as Parkinson's, Alzheimer's, addiction, depression, and pain.
The device, using Lego-like replaceable drug cartridges and Bluetooth low-energy, can target specific neurons of interest using drug and light for prolonged periods.
"The wireless neural device enables chronic chemical and optical neuromodulation that has never been achieved before," said lead author Raza Qazi, a researcher with the Korea Advanced Institute of Science and Technology (KAIST) and University of Colorado Boulder.
In a statement, Qazi said this technology overshadows conventional methods used by neuroscientists, which often involve rigid metal tubes and optical fibres to deliver drugs and light. Apart from limiting the subject's movement because of the physical connections with the equipment, their relatively rigid structure eventually causes lesion in soft brain tissue, making them unsuitable for long-term implantation.
To mitigate against this, efforts have been made to incorporate soft probes and wireless platforms, but these solutions have been limited by their inability to deliver drugs for long periods of time and their bulky and complex control setups.
To achieve chronic wireless drug delivery, scientists had to solve the dual challenge of exhaustion and evaporation of drugs. Researchers from the Korea Advanced Institute of Science and Technology (KAIST) and the University of Washington in Seattle collaborated to invent a neural device with a replaceable drug cartridge, which could allow neuroscientists to study the same brain circuits for several months without worrying about running out of drugs.
These 'plug-n-play' drug cartridges were assembled into a brain implant for mice with a soft and ultrathin probe - which consisted of microfluidic channels and tiny LEDs - for unlimited drug doses and light delivery.
Controlled with a user interface on a smartphone, neuroscientists can trigger any specific combination or precise sequencing of light and drug deliveries in any implanted target animal without the need to be inside the laboratory. Using these wireless neural devices, researchers could also easily set up fully automated animal studies where behaviour of one animal could positively or negatively affect behaviour in other animals by conditional triggering of light and/or drug delivery.
"This revolutionary device is the fruit of advanced electronics design and powerful micro and nanoscale engineering," said Jae-Woong Jeong, a professor of electrical engineering at KAIST. "We are interested in further developing this technology to make a brain implant for clinical applications."
Michael Bruchas, a professor of anaesthesiology and pain medicine and pharmacology at the University of Washington School of Medicine, said this technology will help researchers in many ways.
"It allows us to better dissect the neural circuit basis of behaviour, and how specific neuromodulators in the brain tune behaviour in various ways," he said. "We are also eager to use the device for complex pharmacological studies, which could help us develop new therapeutics for pain, addiction, and emotional disorders."