An upconverted afterglow color conversion strategy for in-situ activated persistent luminescent imaging of medical implants

Abstract

Upconverted afterglow imaging presents a promising avenue for long-term auto-fluorescence-free imaging applications without the necessity of expensive time-resolved equipment. In this research, inspired by LED design, we devised a straightforward ternary upconverted afterglow conversion (UAC) strategy that amalgamates upconversion NaYbF4: Tm0.005 (UP), afterglow ZnS:Cu,Co (AP), and color conversion CaAlSiN3:Eu phosphors (CP). This fusion resulted in a UAC composite that displays a deep-red to near-infrared (NIR) afterglow with a peak at 663 nm, following a brief activation period by 980 nm light. Importantly, an enhancement of 116 times was realized by using the UAC strategy when comparing with a typical single phase afterglow phosphor, Zn3Ga2SnO8:Cr,Yb,Er. The NIR-rechargeable afterglow sustained for a minimum of 100 min after a mere 3 s of NIR wireless charging process and is chemically stable. This makes it highly suitable for long-term luminescence imaging applications. To demonstrate its potential, we employed our ternary UAC phosphor to image medical plastic prostheses through pig skin in vitro and simulated a plastic surgery on a mouse model in vivo. Such luminescent information could prove invaluable for planning future surgical interventions, such as prosthesis replacement, removal, or necessary debris cleaning.