Development of fluorescent materials for Diffuse Fluorescence Tomography standards and phantoms

Area of Science:

• Biomedical Optics
• Materials Science

Background:

• Fluorescence imaging and diffuse optical tomography require reliable standards.
• Developing materials with stable and predictable fluorescence is essential for accurate measurements.

Purpose of the Study:

• To investigate methods for creating diffuse fluorescent materials for use as standards in diffuse fluorescent tomography.
• To evaluate silicone rubber and polyester casting resin as base materials for fluorescence standards.

Main Methods:

• Two base materials (silicone rubber, polyester casting resin) were modified with pigments or nanoparticles to tune optical properties.
• Time-resolved methods were used to characterize optical properties.
• Various near-infrared fluorophores (hydrophobic and hydrophilic) were incorporated to assess fluorescence characteristics.

Main Results:

• Both silicone and resin materials exhibited diffusive fluorescence properties when incorporating appropriate fluorophores.
• Hydrophobic fluorophores (IR 676, IR 780 Iodide) in silicone and hydrophilic fluorophores (Cy5.5, AF 750) in resin were successfully incorporated.
• Only the hydrophobic fluorophores embedded in silicone demonstrated stable fluorescence intensity over time and a linear relationship with concentration, meeting standard criteria.

Conclusions:

• Silicone rubber serves as a suitable base material for developing stable fluorescence standards.
• Hydrophobic fluorophores are recommended for creating reliable diffuse fluorescence standards due to their stability and concentration linearity.