Sensing Reactive Oxygen Species with Photoacoustic Imaging Using Conjugation-Extended BODIPYs.

Area of Science:

• Biomedical Engineering
• Chemical Biology
• Molecular Imaging

Background:

• Reactive oxygen species (ROS) are crucial in physiology but implicated in tissue dysfunction when overproduced.
• Noninvasive detection of ROS is challenging but vital for understanding disease.
• Existing methods struggle to differentiate pathological ROS levels from physiological concentrations.

Purpose of the Study:

• To develop a novel method for noninvasive detection of reactive oxygen species (ROS) overproduction.
• To utilize conjugated BODIPY probes (ROS-BODIPYs) for photoacoustic (PA) and fluorescence imaging.
• To create a probe system that can distinguish between physiological and overproduced ROS levels.

Main Methods:

• Conjugated BODIPY probes (ROS-BODIPYs) were synthesized and characterized.
• The probes' spectral and fluorescence properties upon reaction with ROS were analyzed.
• In vivo photoacoustic and fluorescence imaging were performed using ROS-BODIPYs.
• Reversibility of the probe activation was tested using reducing agents like citric acid.

Main Results:

• ROS interaction with ROS-BODIPYs caused a ~100 nm redshift in absorption (700-800 nm) and fluorescence quenching.
• Strong photoacoustic signals were generated upon ROS activation.
• ROS-BODIPY activation was reversible with reducing agents, returning to the original state.
• The probe system successfully detected overproduced ROS in vivo, distinguishing it from physiological levels.

Conclusions:

• ROS-BODIPYs enable sensitive and specific detection of ROS overproduction using photoacoustic and fluorescence imaging.
• The reversibility of ROS-BODIPY activation allows for selective imaging of pathological ROS levels.
• ROS-BODIPYs show significant translational potential for diagnosing conditions associated with ROS overproduction.