Near-infrared photoactivatable nitric oxide donors with photoacoustic readout

Nitric-Oxide-Releasing aza-BODIPY: A New Near-Infrared J-Aggregate with Multiple Antibacterial Modalities

The development of near-infrared (NIR) J-aggregates has received increasing attention due to their broad applications. Here, we report the nitrosation of an amine-containing aza-BODIPY precursor (BDP-NH₂ ), affording the first nitric oxide (NO)-releasing NIR J-aggregate (BDP-NO). The introduction of N-nitrosamine moieties efficiently inhibits the aromatic interactions of BDP-NH₂ , which instead promotes the formation of J-aggregates within micellar nanoparticles with a remarkable bathochromic shift of ≈109 nm to the NIR window (820 nm). Interestingly, the NO release and photothermal conversion efficiency (PTCE) can be delicately tuned by the loading contents of BDP-NO within micellar nanoparticles, thereby enabling multiple antibacterial modalities by exploring either NO release, photothermal therapy (PTT), or both. We demonstrate the combination of NO and PTT can elevate antibacterial activity while attenuating PTT-associated inflammation for the in vivo treatment of MRSA infection.

A general strategy to optimize the performance of aza-BODIPY-based probes for enhanced photoacoustic properties

In this chapter, we describe a generalizable strategy to obtain a high PA output platform that is optimized for ratiometric imaging. Our approach entails conformationally restricting pendant aryl rings on the aza-BODIPY core to enhance orbital overlap which consequently increases the extinction coefficient. This strategy can potentially be applied to other dye platforms to enhance their signal intensity. We provide detailed protocols for the synthesis, in vitro characterization, and in vivo application.