Design and Integration of a Fiber-Optic Platform for Multi-Metabolite Sensing
The project aims at the development of an optical fiber-based sensor for continuous, minimally invasive monitoring of multiple metabolites in the interstitial fluid. The sensing mechanism relies on Aggregation-Induced Emission luminogens (AIEgens) immobilized in a coating matrix at the fiber tip. Upon LED excitation, the AIEgens emit fluorescence with spectral features that depend on the local metabolite concentration. The signal is guided through a multi-mode optical fiber terminated with a custom microlens and recorded by a spectrometer.
A central challenge in this architecture is the efficient coupling of light at the fiber–coating–tissue interface. The microlens geometry at the fiber facet directly determines excitation efficiency, collection angle, and signal-to-noise ratio, and therefore the limit of detection of the sensor. With the generous support of the Berne University Research Foundation, we acquired a licensed version of Ansys Academic Research Optics (Zemax). This optical design software enables quantitative ray-tracing simulations and tolerance analysis of the fiber tip geometry, the coating matrix, and the coupling optics. It allows us to model and optimize microlens shapes on the fiber facet, evaluate optical losses at material interfaces, and refine fiber coupling strategies prior to fabrication, thereby reducing trial-and-error iterations in the experimental workflow.
Dr. Guglielmo Risi
Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism
samlab.org
