Multiplexed Shortwave Infrared Imaging Highlights Anatomical Structures in Mice.

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Quantum Dot Development

Background:

• Visible and traditional near-infrared (NIR-I) light imaging is limited by tissue scattering and attenuation.
• Shortwave infrared (SWIR, also known as NIR-II) imaging offers deeper tissue penetration and reduced background autofluorescence.
• SWIR-emitting quantum dots (QDs) are promising contrast agents but multiplexed SWIR imaging is underexplored.

Purpose of the Study:

• To engineer and demonstrate simultaneous three-color SWIR fluorescence imaging using novel quantum dots.
• To evaluate the application of these SWIR QDs for longitudinal lymphatic imaging.
• To visualize the lymphatic and vasculature systems in mice using multiplexed SWIR imaging.

Main Methods:

• Fabrication of three high-quality lead sulfide/cadmium sulfide (PbS/CdS) core/shell quantum dots with distinct SWIR emission peaks (1100-1550 nm).
• Longitudinal in vivo imaging of lymphatic drainage in mice using the photostable QDs over a 2-hour period.
• Multiplexed in vivo imaging of lymphatic and vasculature networks in mice using all three engineered SWIR QDs.

Main Results:

• Successfully achieved simultaneous three-color SWIR imaging in mice.
• Demonstrated non-invasive, longitudinal tracking of lymphatic drainage with detailed visualization of lymphatic vessels.
• Clearly distinguished overlapping lymphatic and vasculature networks, including specific organs like the liver and spleen.

Conclusions:

• Engineered SWIR QDs are optimized for next-generation multiplexed and longitudinal preclinical imaging.
• This technology enhances visualization of biological systems, overcoming limitations of traditional imaging wavelengths.
• Opens new avenues for preclinical studies on disease progression, drug delivery, and cell dynamics.