Polyacrylamide-based phantoms of human skin for hyperspectral fluorescence imaging and spectroscopy

Based on the combined use of polymerisable polyacrylamide, collagen and an aqueous solution of Flavin adenine dinucleotide (FAD), we have developed a new technique for fabrication of composite phantoms mimicking fluorescence properties of human skin. A comparative analysis of the absorption and scattering coefficients, refractive indices, as well as fluorescence spectra of phantoms with different concentrations of FAD measured with the combined use of a CCD spectrometer and a hyperspectral camera is presented. To obtain values of scattering coefficients close to those for human skin, zinc oxide (ZnO) nanoparticles are added to the polyacrylamide polymer structure. Variations both in the shape of the spectrum and in the intensity of the fluorescence signal in the phantoms are provided by the changes in the volume fraction of FAD and collagen. It is shown that the model fluorescence spectra are in good agreement with the results of direct human skin measurements in vivo.