Phthalocyanine-based photoacoustic contrast agents for imaging and theranostics.

Phthalocyanine, as an organic dye, has attracted much attention due to its high molar absorption coefficient in the near-infrared (NIR) region. It is precisely because of this advantage that phthalocyanine is very beneficial to photoacoustic imaging (PAI). At present, many different strategies have been adopted to design phthalocyanine-based contrast agents with photoacoustic (PA) effect, including increasing water solubility, changing spectral properties, prolonging circulation time, constructing activatable supramolecular nanoparticles, increasing targeting, etc. Based on this, this minireview highlights the above ways to enhance the PA effect of phthalocyanine. What`s more, the application of phthalocyanine-based PA contrast agents in biomedical imaging and image-guided phototherapy are discussed, herein, in this minireview. Finally, this minireview also provides the prospects and challenges of phthalocyanine-based PA contrast agents. In order to provide some reference for the application of phthalocyanine-based PA contrast agent in biomedical imaging and guiding tumor treatment.