Size-Controlled Self-Assembly for Bimodal In Vivo Imaging

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Contrast agents (CAs) are crucial for disease diagnosis and therapy monitoring in biomedical imaging.
• Current CAs are limited to single modalities and possess fixed properties, hindering comprehensive biological process visualization.
• Developing versatile CAs is essential for advancing diagnostic capabilities.

Purpose of the Study:

• To introduce a novel platform of rationally designed dye assemblies for simultaneous multimodal and multiscale biomedical imaging.
• To synthesize amphiphilic aza-BODIPY dyes and investigate their self-assembly into nanostructures with tunable properties.
• To establish the utility of these nanostructures for advanced in vitro and in vivo imaging applications.

Main Methods:

• Synthesis of amphiphilic aza-BODIPY dyes with varying hydrophobic alkyl chain lengths (C1, C8, C12, C16).
• Characterization of self-assembly into nanostructures in aqueous media with tunable size (50 nm-1 µm) and photophysical properties.
• Establishment of fluorescence reflectance and photoacoustic imaging (in vitro and in vivo), cell viability assays, and biodistribution studies.

Main Results:

• Aza-BODIPY dyes self-assembled into nanostructures with J-type aggregation, exhibiting near-infrared (NIR) absorption/emission and photoacoustic properties (C8-C16).
• Demonstrated successful semi-quantitative fluorescence reflectance and photoacoustic imaging in vitro and in vivo.
• Confirmed excellent biocompatibility and size-dependent biodistribution of nanostructures in vivo.

Conclusions:

• Rationally designed aza-BODIPY dye assemblies provide a versatile platform for multimodal and multiscale biomedical imaging.
• The self-assembly approach allows for tunable nanostructure size and photophysical properties, overcoming limitations of traditional CAs.
• This technology holds significant potential for addressing complex biomedical questions and advancing diagnostic imaging.