Vascular tree structure-based perfusion phantom fabrication using modified Hele-Shaw cell method

Abstract

Tissue phantoms mimicking microvasculature and perfusion are essential for vasculature modelling and calibrating imaging systems, which require faithful replication of vascular geometry and flow. Conventional fabrication methods, including lithographic micromachining and additive manufacturing remain constrained by predefined designs, rectangular channel cross-sections, limited scalability, and high production costs. Here we present a lithography-free approach based on a modified lifted Hele-Shaw cell method where, unlike above-mentioned methods, random fractal-like vascular structures emerge naturally. This results in channels of widths 100-1000 μm with smooth Gaussian cross-section and natural diameter tapering. We demonstrate this with four phantom designs: a planar vascular tree, a cerebral vasculature-mimicking guided tree network, a conformable curved substrate and a retinal vasculature-mimicking network. Flow visualisation with laser speckle contrast imaging shows close agreement with in vivo observations and consistency with the generalized Murray’s law. This approach uniquely combines fractal-like network formation leading towards realistic vascular geometry and flow characteristics, offering an in vitro alternative to small animal vascular models.