Laser-excited photoluminescence of Cs-137 gamma-preconditioned ZnO on ex vivo chicken skin: Concentration-dependent optical enhancement and Biophotonic Implications.

This exploratory study compared surface and optical properties of non-equivalent ZnO formulations deposited on ex vivo chicken skin. Non-irradiated ZnO mixture was compared to nominally 137 Cs-exposed ZnO prepared in multiple dilutions. An approximate unshielded air-kerma of 81.6 mGy nominal was obtained by point-source calculation. The irradiation was performed for 24 h using a source of 119 μCi. The Non-irradiated ZnO showed only hexagonal wurtzite ZnO from XRD results. FESEM images projected minor-axis widths of the specimens varied between 11.5 nm and 19.9 nm. FTIR bands were distinct and in agreement with the surface species with O-H, depending on the formulation. EDX showed only elemental peaks of Zn and O. Single AFM scans and UV-vis spectra revealed differences in formulation. Sample 2 showed the narrowest PL band (FWHM = 14.2 nm) under 355 nm excitation, compared to the other samples, and Sample 3 showed the highest raw peak intensity. ZnO mass, water volume, coating thickness, dispersion and skin-specimen variability were confounders of irradiation status. The differences observed could not be explained by gamma exposure alone. Hence, these hypothesis-generating results define the controls, replication and dosimetry required for a confirmatory study.