Contrasting properties of zinc oxide nanoparticles and titanium dioxide nanoparticles for optical coherence tomography imaging of human normal endometrium tissues and uterine leiomyoma tissues in ex vivo study combined with microneedle

The aims of this study were to monitor and contrast the diffusion of zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles' (NPs) penetration and accumulation in human normal endometrium (NE) tissues and uterine leiomyoma (UL) tissues combined with microneedles (MN) in vitro using optical coherence tomography (OCT) and diffuse reflectance (DR) spectral. Continuous OCT and DR spectra monitoring showed that, after application of ZnO or TiO2 NPs, the OCT signal intensities of NE and UL both increase with time, and the TiO2 NPs tend to produce a greater signal enhancement than ZnO NPs in the same type of tissue. And for the same type of NPs, they penetrate faster in NE tissue compared with UL tissue. In addition, the use of MN can significantly enhance the penetration of topically applied ZnO or TiO2 NPs in the tissue. The attenuation coefficients of NE tissue are about 5.01 +/- 0.35 mm(-1) for ZnO NPs treatment at 195 min and 4.62 +/- 0.29 mm(-1) for ZnO NPs/MN at 179 min, 4.73 +/- 0.30 mm(-1) for TiO2 NPs at 183 min, 4.05 +/- 0.25 mm(-1) for TiO2 NPs/MN at 147 min when the penetration process reached the stable state. And the attenuation coefficients of UL tissue are about 5.0 +/- 0.34 mm(-1) for ZnO NP treatment at 191 min and 4.20 +/- 0.26 mm(-1) for ZnO NPs/MN at 169 min, 4.33 +/- 0.27 mm(-1) for TiO2 NPs at 176 min, 3.53 +/- 0.20 mm(-1) for TiO2 NPs/MN at 141 min when the penetration process reached the stable state. This suggests that TiO2 NPs penetrate faster and reach the maximum amount of penetration earlier than ZnO NPs with the same condition. The results of attenuation coefficients and reflectance intensity of NE and UL tissue suggests that the accumulation of the TiO2 or ZnO NPs in both NE and UL tissue greatly influenced the tissue optical properties.