Self-assembled AIEgen nanoparticles for multiscale NIR-II vascular imaging

Area of Science:

• Biomedical Engineering
• Materials Science
• Optical Imaging

Background:

• Aggregation-induced emission (AIE) fluorogens (AIEgens) are promising for biomedical applications but face challenges due to hydrophobicity.
• Encapsulating hydrophobic AIEgens in nanoparticles is a common strategy, yet achieving uniform size and stable loading remains difficult.
• Developing reliable methods for creating uniform AIE nanoparticles for biological applications is crucial.

Purpose of the Study:

• To design and synthesize novel amphiphilic AIEgens capable of self-assembly into uniform nanoparticles.
• To evaluate the performance of these AIE nanoparticles for fluorescence imaging in the second near-infrared window (NIR-II).
• To demonstrate a new strategy for constructing advanced AIE nanoparticles for angiography.

Main Methods:

• Rational design of amphiphilic AIEgens incorporating a hydrophobic donor-acceptor-donor (D-A-D) core and a hydrophilic polyethylene glycol (PEG) chain.
• Self-assembly of amphiphilic AIEgens into nanoparticles.
• Characterization of nanoparticle size, emission properties (wavelength, quantum yield), and application in intravital vascular fluorescence imaging in mouse and rabbit models.

Main Results:

• Amphiphilic AIEgens self-assembled into uniform nanoparticles with an average size of approximately 35 nm.
• The nanoparticles exhibited strong emission beyond 1000 nm with quantum yields exceeding 10%, suitable for NIR-II imaging.
• High-resolution (~38 μm) and deep-penetration (~1 cm) vascular imaging was achieved in animal models.

Conclusions:

• An efficient self-assembly strategy was developed for constructing advanced AIE nanoparticles.
• The designed amphiphilic AIEgens and their self-assembled nanoparticles are effective for multiscale intravital vascular imaging in the NIR-II window.
• This approach offers a promising method for developing AIE nanoparticles for angiography and other biomedical imaging applications.