Multiplexed Short-wave Infrared Imaging Highlights Anatomical Structures in Mice

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Optical Engineering

Background:

• Multiplexed fluorescence imaging is limited in vivo by light scattering and attenuation at visible and traditional near-infrared (NIR-I) wavelengths.
• Short-wave infrared (SWIR, 1000–1700 nm, also known as NIR-II) imaging offers deeper tissue penetration and reduced background autofluorescence for preclinical applications.
• Current SWIR imaging is typically limited to two-color schemes, restricting multiplexing capabilities.

Approach:

• Engineered three distinct, high quantum yield lead sulfide/cadmium sulfide (PbS/CdS) core/shell quantum dots (QDs) with tunable SWIR emissions (1100–1550 nm).
• Utilized these QDs for simultaneous three-color fluorescence imaging in mouse models.
• Demonstrated non-invasive tracking of lymphatic drainage and visualization of lymphatic and vasculature networks.

Key Points:

• Achieved simultaneous three-color SWIR imaging in mice using novel PbS/CdS core/shell QDs.
• Successfully visualized detailed lymphatic vessel networks over a 2-hour period.
• Distinguished spatially overlapping lymphatic and vasculature networks using multiplexed SWIR imaging.

Conclusions:

• Developed optimized SWIR QDs for next-generation multiplexed preclinical imaging, surpassing previous dual-labeling limitations.
• The ability to discriminate multiple fluorescent labels via NIR-I excitation and SWIR detection opens new avenues for disease progression, drug biodistribution, and cell trafficking studies.
• This technique enhances non-invasive anatomical imaging in small animal models.