Plasmonic Copper Sulfide Nanoparticles Enable Dark Contrast in Optical Coherence Tomography

Area of Science:

• Biomedical Optics
• Nanotechnology
• Medical Imaging

Background:

• Optical coherence tomography (OCT) is a key noninvasive imaging technique.
• Contrast agents enhance biological feature discernment in OCT.
• Existing OCT contrast agents are primarily "bright" (scattering-based), with no "dark" counterparts developed.

Purpose of the Study:

• To develop the first dark contrast agents for OCT.
• To utilize plasmonic copper sulfide nanoparticles for this purpose.
• To explore their application in the second optical transparency window.

Main Methods:

• Synthesis of plasmonic copper sulfide nanoparticles.
• Characterization of nanoparticle optical properties at ≈1300 nm (second optical transparency window).
• Assessment of nanoparticle light scattering and absorption capabilities.
• Evaluation of nanoparticle cytotoxicity for biomedical applications.

Main Results:

• Copper sulfide nanoparticles function as the first dark contrast agents for OCT.
• These nanoparticles exhibit minimal light scattering and strong light absorption at ≈1300 nm, producing dark contrast.
• The nanoparticles are small and show no apparent cytotoxicity.
• A library of copper sulfide nanoparticles with tunable plasmonic resonances across three optical transparency windows was created.

Conclusions:

• Plasmonic copper sulfide nanoparticles are effective dark contrast agents for OCT.
• They offer a novel approach for enhanced biomedical imaging.
• Their tunable optical properties highlight their potential in various light-controlled biomedical applications.