Imaging with second-harmonic radiation probes in living tissue

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Nonlinear Optics

Background:

• Developing advanced imaging techniques is crucial for in vivo diagnostics.
• Nanoparticles offer unique optical properties for contrast enhancement.
• Second-harmonic generation (SHG) provides intrinsic signal generation without exogenous agents.

Purpose of the Study:

• To evaluate barium titanate (BaTiO3) nanoparticles as efficient contrast markers for second-harmonic radiation imaging in living tissues.
• To determine the penetration depth capabilities of these nanoparticles in biological samples.
• To validate experimental findings with computational simulations.

Main Methods:

• Utilized barium titanate (BaTiO3) nanoparticles of 100 nm and 300 nm sizes.
• Employed second-harmonic radiation imaging techniques.
• Conducted experiments on ex vivo and in vivo mouse tail tissue.
• Performed Monte Carlo simulations to model light propagation and scattering.

Main Results:

• Demonstrated successful detection of BaTiO3 nanoparticles as contrast markers.
• Achieved imaging through 50 μm of tissue with 100 nm nanoparticles.
• Showed detection through 120 μm of tissue with 300 nm nanoparticles.
• Found excellent agreement between experimental data and Monte Carlo simulations.

Conclusions:

• Second-harmonic radiation imaging probes, specifically BaTiO3 nanoparticles, are efficient biomarkers for deep tissue imaging.
• These nanoparticles exhibit significant penetration capabilities in biological tissues.
• The findings support the potential of SHG imaging with nanoparticle contrast agents for in vivo biomedical applications.