3D-bioprinted Phantom with Human Skin Phototypes for Biomedical Optics.

We report 3D-bioprinted skin-mimicking phantoms with skin colors ranging across the Fitzpatrick scale. These tools can help understand the impact of skin phototypes on biomedical optics. Synthetic melanin nanoparticles of different sizes (70-500 nm) and clusters were fabricated to mimic the optical behavior of melanosome. The absorption coefficient and reduced scattering coefficient of the phantoms are comparable to real human skin. We further validated the melanin content and distribution in the phantoms versus real human skins via photoacoustic (PA) imaging. The PA signal of the phantom could be improved by (i) increasing melanin size (3-450-fold), (ii) increasing clustering (2-10.5-fold), and (iii) increasing concentration (1.3-8-fold). We then used multiple biomedical optics tools (e.g., PA, fluorescence imaging and photothermal therapy) to understand the impact of skin tone on these modalities. These well-defined 3D-bioprinted phantoms may have value in translating biomedical optics and reducing racial bias. This article is protected by copyright. All rights reserved.