Remote diffuse reflectance spectroscopy sensor for tissue engineering monitoring based on blind signal separation

Spatial frequency domain imaging: a quantitative, noninvasive tool for in vivo monitoring of burn wound and skin graft healing

There is a need for noninvasive, quantitative methods to characterize wound healing in the context of longitudinal investigations related to regenerative medicine. Such tools have the potential to inform the assessment of wound status and healing progression and aid the development of new treatments. We employed spatial frequency domain imaging (SFDI) to characterize the changes in optical properties of tissue during wound healing progression in a porcine model of split-thickness skin grafts and also in a model of burn wound healing with no graft intervention. Changes in the reduced scattering coefficient measured using SFDI correlated with structural changes reported by histology of biopsies taken concurrently. SFDI was able to measure spatial inhomogeneity in the wounds and predicted heterogeneous healing. In addition, we were able to visualize differences in healing rate, depending on whether a wound was debrided and grafted, versus not debrided and left to heal without intervention apart from topical burn wound care. Changes in the concentration of oxy- and deoxyhemoglobin were also quantified, giving insight into hemodynamic changes during healing.

In-vivo, non-invasive detection of hyperglycemic states in animal models using mm-wave spectroscopy

Chronic or sustained hyperglycemia associated to diabetes mellitus leads to many medical complications, thus, it is necessary to track the evolution of patients for providing the adequate management of the disease that is required for the restoration of the carbohydrate metabolism to a normal state. In this paper, a novel monitoring approach based on mm-wave spectroscopy is comprehensively described and experimentally validated using living animal models as target. The measurement method has proved the possibility of non-invasive, in-vivo, detection of hyperglycemia-associated conditions in different mouse models, making possible to clearly differentiate between several hyperglycemic states.

Dual electro-optic optical frequency combs for multiheterodyne molecular dispersion spectroscopy

In this paper, a multiheterodyne architecture for molecular dispersion spectroscopy based on a coherent dual-comb source generated using a single continuous wave laser and electro-optic modulators is presented and validated. The phase-sensitive scheme greatly simplifies previous dual-comb implementations by the use of an electro-optic dual comb and by phase-locking all the signal generators of the setup eliminating, in this way, the necessity of any reference optical path currently mandatory in absorption-based instruments. The architecture is immune to the classical baseline and normalization problems of absorption-based analyzers and provides an output linearly dependent on the gas concentration. In addition, the simultaneous parallel multi-wavelength measurement approach has the ability to deliver an improved output bandwidth (measurement speed) over gas analyzers based on tunable lasers.