Probe Delivers Fluids, Light To Brain

Collaboration between neuroscientists and materials scientists has yielded a new minimally invasive neural probe and wireless device that delivers liquid pharmaceuticals and light stimulation to brain tissue in mice and rats (Cell 2015, DOI: 10.1016/j.cell.2015.06.058). At about 80 µm thick and 500 µm wide, the soft, flexible polydimethylsiloxane (PDMS) probe caused a less severe inflammatory response than did conventional metal cannulas and optic fibers. The system, mounted on a rodent’s head, pumps fluids from four reservoirs through four 10-µm-wide channels deep into brain tissue. A cellular-scale LED array on the transparent probe allows for photostimulation. In one experiment, rodents received an opioid agonist through the device that caused them to spin in circles—a behavior that stopped when the device switched to delivering a control substance. The researchers, led by electrical engineer Jae-Woong Jeong of the University of Colorado, Boulder; Washington University in St. Louis neuroscience graduate student Jordan G. McCall; and John A. Rogers of the University of Illinois, Urbana-Champaign, say the wireless optofluidic system may help neuroscientists study the brains of freely moving animals with less animal-researcher interaction, which can skew results.