Stain-free LED scanning lifetime imaging system for diabetes modified tissue matrices

Area of Science:

• Biophotonics
• Medical Imaging
• Biochemistry

Background:

• Histological techniques for diabetic ulcers are labor-intensive and destructive.
• Intrinsic autofluorescence lifetimes of extracellular matrix proteins offer label-free imaging of tissue modifications.
• Current instrumentation for fluorescence lifetime analysis is complex and costly.

Purpose of the Study:

• To design and demonstrate a low-complexity, accessible imaging system for analyzing diabetic tissue.
• To characterize autofluorescent and fluorogenic proteins in diabetic ulcers using fluorescence lifetime measurements.
• To establish lifetime standards for developing a biophotonic model of diabetic ulcers.

Main Methods:

• Developed a frequency domain light-emitting diode (LED) modulation imaging system using off-the-shelf components.
• Optimized system performance for scanning and signal acquisition based on etendues.
• Measured fluorescence lifetimes of purified and pentosidine-modified collagen I, collagen III, and elastin.
• Applied phasor analysis to interpret lifetime images of a diabetic foot ulcer.

Main Results:

• Pentosidine modification led to a decrease in autofluorescent lifetimes.
• Elevated collagen III in diabetic ulcers showed increased fluorescence lifetimes.
• Successfully imaged a 3 cm × 3 cm diabetic foot ulcer using the developed system.

Conclusions:

• Achieved a compact biophotonic imaging system for diabetic tissue analysis.
• The system provides a more accessible method for fluorescence lifetime imaging in clinical histology.
• Established baseline lifetime measurements for key proteins in diabetic ulcers, enabling future diagnostic models.