Monte Carlo modeling for implantable fluorescent analyte sensors

Area of Science:

• Biomedical Optics
• Biophotonics
• Medical Device Design

Background:

• Optical probes are crucial for implantable fluorescent sensors used in biomedical monitoring.
• Understanding photon propagation and interaction within biological tissues is essential for probe design.

Purpose of the Study:

• To develop a Monte Carlo simulation for photon propagation through human skin.
• To analyze light interaction with a subcutaneous fluorescent sensing layer.
• To guide the design of an optical probe for an implantable fluorescent sensor.

Main Methods:

• Monte Carlo simulation of photon propagation and interaction.
• Analysis of output light intensity, photon exit angle, and fluorescence ratios (sensor fluorescence vs. tissue autofluorescence).
• Sensitivity study on optical properties, tissue/sensor layer thickness, and quantum yields.

Main Results:

• Skin optical properties and layer thickness significantly impact signal output.
• Sensor fluorescence spatial emission is broader than tissue autofluorescence.
• The ratio of sensor to tissue fluorescence increases with distance from the source.

Conclusions:

• Simulation results provide critical insights for optimizing optical probe design.
• The study highlights the influence of tissue optical properties and geometry on sensor performance.
• Findings aid in developing effective optics for collecting fluorescence signals from subcutaneous sensors.