Multifunction‐Harnessed Afterglow Nanosensor for Molecular Imaging of Acute Kidney Injury In Vivo

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-06, Vol.18 (22), p.e2200245-n/a
• Main Authors: Anjong, Tikum Florence, Choi, Honghwan, Yoo, Jounghyun, Bak, Yecheol, Cho, Yuri, Kim, Dojin, Lee, Seokyung, Lee, Kangwon, Kim, Bong‐Gi, Kim, Sehoon
• Format: Article
• Language: English
• Subjects: afterglow; Biomedical materials; Imaging; Injuries; Iridium compounds; Kidneys; Luminescence; multifunctional iridium complexes; Nanoparticles; Nanosensors; Nanotechnology; Phosphorescence; Singlet oxygen; Substrates; superoxide‐activatable afterglow systems
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202200245

Afterglow is superior to other optical modalities for biomedical applications in that it can exclude the autofluorescence background. Nevertheless, afterglow has rarely been applied to the high‐contrast “off‐to‐on” activatable sensing scheme because the complicated afterglow systems hamper the additional inclusion of sensory functions while preserving the afterglow luminescence. Herein, a simple formulation of a multifunctional components‐incorporated afterglow nanosensor (MANS) is developed for the superoxide‐responsive activatable afterglow imaging of cisplatin‐induced kidney injury. A multifunctional iridium complex (Ir‐OTf) is designed to recover its photoactivities (phosphorescence and the ability of singlet oxygen‐generating afterglow initiator) upon exposure to superoxide. To construct the nanoscopic afterglow detection system (MANS), Ir‐OTf is incorporated with another multifunctional molecule (rubrene) in the polymeric micellar nanoparticle, where rubrene also plays dual roles as an afterglow substrate and a luminophore. The multiple functions covered by Ir‐OTf and rubrene renders the composition of MANS quite simple, which exhibits superoxide‐responsive “off‐to‐on” activatable afterglow luminescence for periods longer than 11 min after the termination of pre‐excitation. Finally, MANS is successfully applied to the molecular imaging of cisplatin‐induced kidney injury with activatable afterglow signals responsive to pathologically overproduced superoxide in a mouse model without autofluorescence background. An activatable afterglow nanosensor formulated with two multifunctional components (MANS) is developed for the superoxide‐responsive afterglow imaging of cisplatin‐induced kidney injury in vivo. MANS enables activatable afterglow imaging of O2·− overproduced in the injured kidney tissue of an AKI mouse model by in situ pre‐excitation, demonstrating potential of the background‐free afterglow signal for diagnostic molecular imaging in vivo.