Skin-equivalent opto-/elastofluidic in-vitro microphysiological vascular models for translational studies of optical biopsies

Abstract

The skin equivalent opto-/elastofluidic in-vitro microphysiological vascular models are prepared as the functional validation test charts to evaluate the correctness of the bio-optical measurements/imaging. The opto-/elastofluidic models are constructed with the TiO2/molecular dye insertions. The tissue equivalences to the cutaneous tissue of human are characterized. It is proved that these opto-/elastofluidics can withstand high liquid pressure up to 6 bar and high flow rate of 10 mL/min to allow the simulation of the real blood hydraulics. It is also proved that the in-vivo skin optical parameters μa and μ‘s of the human volunteers match the elastofluidic phantoms. The Young’s moduli E of the elastofluidic phantom matrices are manipulated to give the same reaction to the mechanical load as the real soft skin cutis. The speed of sound propagating through the PVCp matrices is tailored at 1350 to 1500 m/s, which approach that in the real tissue of about 1540 m/s. The diffuse optical biopsy is built to measure the optical path length factors of all major chromophores of the artificial hemoglobin dilutions included in the phantoms. For both oxy- and deoxygenated hemoglobin, the concentration dependencies of the optical path length factors are defined as fPf (Ct) ~ Ct-0.5. Preliminary human experiments are done on the suspicious spider nevi and the embedded nodule lesion, and prove the tissue equivalences of the microphysiological elastofluidic skin models.