Surfactant‐Stripped Micelles for NIR‐II Photoacoustic Imaging through 12 cm of Breast Tissue and Whole Human Breasts

Surfactant‐stripped micelles are formed from a commercially available cyanine fluoroalkylphosphate (CyFaP) salt dye and used for high contrast photoacoustic imaging (PAI) in the second near‐infrared window (NIR‐II). The co‐loading of Coenzyme Q10 into surfactant‐stripped CyFaP (ss‐CyFaP) micelles improves yield, storage stability, and results in a peak absorption wavelength in the NIR‐II window close to the 1064 nm output of Nd‐YAG lasers used for PAI. Aqueous ss‐CyFaP dispersions exhibit intense NIR‐II optical absorption, calculated to be greater than 500 at 1064 nm. ss‐CyFaP is detected through 12 cm of chicken breast tissue with PAI. In preclinical animal models, ss‐CyFaP is visualized in draining lymph nodes of rats through 3.1 cm of overlaid chicken breast tissue. Following intravenous administration, ss‐CyFaP accumulates in neoplastic tissues of mice and rats bearing orthotopic mammary tumors without observation of acute toxic side effects. ss‐CyFaP is imaged through whole compressed human breasts in three female volunteers at depths of 2.6–5.1 cm. Taken together, these data show that ss‐CyFaP is an accessible contrast agent for deep tissue PAI in the NIR‐II window. A commercially available NIR‐II dye is encapsulated in Pluronic micelles and subjected to surfactant stripping. This results in the concentrated dye giving rise to absorption at 1064 nm. Photoacoustic imaging with a 1064 nm laser images the micelles though 12 cm of chicken breast tissue, a variety of preclinical animals models, and through whole human breasts of healthy adult female human volunteers.