Development of solid-state fluorescence lifetime standards for clinical applications using dyed epoxy resins

Area of Science:

• Biophotonics and Medical Imaging
• Materials Science for Biomedical Applications

Background:

• Fluorescence lifetime imaging (FLIm) provides label-free contrast using intrinsic tissue properties, showing promise for clinical diagnostics and intraoperative guidance.
• Current limitations include a lack of robust, reproducible standards for system validation, hindering cross-platform comparability, quality assurance, and clinical translation.

Purpose of the Study:

• To develop and characterize stable solid-state fluorescence lifetime (FLT) standards using dyed epoxy resins.
• To enable reliable calibration, benchmarking, and validation of FLIm systems for research and clinical use.

Main Methods:

• Fabrication of solid standards with various dyes spanning sub-nanosecond to over 3.5 ns lifetimes.
• Evaluation of FLT, emission intensity, photostability, and fabrication repeatability.
• Assessment of dye concentration and microstructural uniformity via confocal microscopy; validation of a chip-on-tip FLIm micro-camera.

Main Results:

• Dyed epoxy standards exhibited consistent, reproducible lifetimes and good photostability with scalable fabrication.
• Confocal imaging showed some microstructural heterogeneity, but bulk measurements were robust.
• Standards effectively validated the FLIm micro-camera, assessing resolution and revealing platform-dependent lifetime estimation biases.

Conclusions:

• Dyed epoxy materials offer a practical and scalable solution for FLIm system calibration and quality assurance.
• These standards can facilitate cross-platform validation and benchmarking of FLIm technologies.
• The developed standards may aid in establishing future regulatory frameworks for clinical adoption of FLIm.