@Article{C9NR07583F,
author ="Wang, Ying and Xie, Kai and Yue, Haibing and Chen, Xian and Luo, Xuan and Liao, Qinghai and Liu, Ming and Wang, Feng and Shi, Peng",
title  ="Flexible and Fully Implantable Upconversion Device for Wireless Optogenetic Stimulation of Spinal Cord in Behaving Animals",
journal  ="Nanoscale",
year  ="2019",
pages  ="-",
publisher  ="The Royal Society of Chemistry",
doi  ="10.1039/C9NR07583F",
url  ="http://dx.doi.org/10.1039/C9NR07583F",
abstract  ="Wireless optogenetics based on upconversion technique recently provides an effective and interference-free alternative for remote brain stimulation and inhibition in behaving animals{,} which is of great promises for neuroscience research. However{,} more versatile upconversion devices are yet implemented for neural tissues other than the brain. In this study{,} a flexible and fully implantable upconversion device is developed for epidural spinal cord stimulation. The upconversion device is fabricated via a straightforward two-step heat-pulling process using biocompatible thermoplastic polypropylene as a backbone{,} which is mixed with upconversion nanoparticles (UCNPs) to form a flexible optrode device that converts near infrared (NIR) irradiation to visible lights for optogenetic manipulation of spinal cord tissues. In this system{,} the flexible upconversion device is fully-implantable within the rigid spine structure{,} and shows excellent long-term biocompatibility even after four month experiment. In anesthetized mice{,} the UCNPs device implanted at L4 vertebra can be used to reliably evoke hindlimb muscular activity upon NIR triggering. In behaving mice{,} neural modulation by the same UCNPs devices effectively inhibits the animals’ movement as a result of remote spinal cord stimulation. We believe that the flexible upconversion device provides new possibilities for wireless neural modulation in spinal cord tissues{,} and will become a valuable supplement to the current toolsets of upconversion based wireless optogenetics."}