Portable Multi-Wavelength Fluorescence Measurement Device

Monitoring-based preventive medicine relies heavily on minimal or noninvasive, portable and cost-effective measurement solutions. This work presents a portable multi-wavelength fluorescence measurement system. The pinhole collimator, Fresnel focusing lens and PIN photo diode provide a cost-effective fluorescent light detection path. The with matte black filament 3D printed housing reduces unwanted reflections along the detection path. The integrated laser diode drivers ensure constant optical output power during operation. This is achieved by utilizing a laser diode package which incorporates both a laser and monitor diode. The monitor diode's output photocurrent is proportional to the optical output power, and thus provides, a feedback path for the driver. An optical diffuser is pre-mounted on each laser diode, providing a uniform illumination of the measurement area. The device adapts to a wide variety of fluorescent dyes by offering exchangeable laser diode modules and support of standard-sized optical thin film filters. The precision integrator transimpedance amplifier applies a switched-input photocurrent measurement technique that ensures the level of sensitivity required for clinical usage. Experimental validation indicates sensitivity in the pico-ampere range. Ex vivo and in vivo measurements, performed by the Faculty of Pharmacy at the Universite de Montreal, confirm that the instrument matches its intended application.