High-efficiency optical systems for interrogation of dermally-implanted sensors

Area of Science:

• Biomedical Engineering
• Optical Sensing Technologies
• Implantable Biosensors

Background:

• Ratiometric luminescent microparticle sensors are developed for biochemical targets like glucose in interstitial fluid.
• Dermal implants enable on-demand monitoring, requiring a matched optoelectronic system for in vivo interrogation.
• Previous system evaluations revealed compromised efficiency due to photon losses in fiber connections and spectrometer components.

Purpose of the Study:

• To investigate methods for overcoming photon loss in optoelectronic systems for dermal implant sensors.
• To address the trade-off between spectral resolution and input light power in existing spectrometer designs.
• To enhance the efficiency and reliability of in vivo biochemical monitoring systems.

Main Methods:

• Investigated replacement of the CCD spectrometer with a two-detector system for spectral information extraction.
• Explored free-space coupling of the optical probe to a custom low-resolution spectrometer.
• Evaluated photon loss through experiments and simulations; constructed preliminary hardware for the two-detector system.

Main Results:

• Identified photon loss points in fiber connections, entrance aperture, and spectrometer slit.
• Developed and simulated two distinct optimization strategies to mitigate these losses.
• Preliminary hardware for a two-detector system was successfully constructed.

Conclusions:

• Two novel methods show promise for enhancing the efficiency of optoelectronic systems for luminescent microparticle sensors.
• These optimizations are crucial for the successful in vivo deployment of dermal implants for continuous monitoring.
• Further development and validation are needed for the proposed custom spectrometer and two-detector system.