Aminophenoxazinone near-infrared fluorescent probes for myelin-specific imaging

Myelin sheath is one of the important tissues in protecting neurons for rapid and accurate signal transduction in the central nervous system. Direct detection and quantification of myelin content in vivo can facilitate diagnosis and therapeutic treatment of myelin-related diseases such as multiple sclerosis. In this work, two aminophenoxazinone derivatives, 2-amino-7-(dimethylamino)-3H-phenoxazin-3-one (ADMPO) and 2-amino-7-(diethylamino)-3H-phenoxazin-3-one (ADEPO), were designed and synthesized using a new method. Their structures were confirmed by 1H NMR, 13C NMR and HRMS analysis. They fluoresce in the near-infrared range with emission wavelengths ranging at 657 nm and 664 nm, respectively. In vitro assays demonstrated that they can specifically bind to myelinated fibers, and ADEPO is superior. This study suggests that aminophenoxazinone derivatives can be used as novel myelin-specific near-infrared fluorescent molecular probes.