Rechargeable afterglow nanotorches for in vivo tracing of cell-based microrobots

Abstract

As one of the self-luminescence imaging approaches that require pre-illumination instead of real-time light excitation, afterglow luminescence imaging has attracted increasing enthusiasm to circumvent tissue autofluorescence. In this work, we developed organic afterglow luminescent nanoprobe (nanotorch), which could emit persistent luminescence more than 10 days upon single light excitation. More importantly, the nanotorch could be remote charged by 660 nm light in a non-invasive manner, which showed great potential for real-time tracing the location of macrophage cell-based microrobots. A near-infrared (NIR) rechargeable nanotorch was devised for in vivo tracking of cell-based microrobots (MRs). The as-prepared nanotorch uses faPT, a methylene blue analog, as a NIR transducer, generating singlet oxygen that prompts the SA570, a modified version of Schaap's 1,2-dioxetane, to produce a 10-day-lasting afterglow. Once its glow fades, the nanotorch can be non-invasively recharged using 660 nm light, highlighting its potential for continuous in vivo MR tracking. image