VITRO‐P: Revolutionizing Optical Tissue Phantoms with Tailored Vascular Structures

Abstract Advancements in optical sensors and spectroscopy have transformed biomedical research, but the lack of standardized benchmarks for evaluating these tools hampers progress. Existing tissue‐mimicking phantoms, essential for testing optical technologies, often lack embedded vasculature, limiting their ability to mimic human tissues. While techniques like bioprinting and millifluidics have made strides in replicating vascular structures, they lack flexibility to control vascular architecture or capture human variability. Using animal or human vasculature scans to fabricate vasculature in optical tissue phantoms often requires extensive effort to clean geometries or modify networks for specific research needs. Here, a novel approach using generative computational design and 3D‐printed sacrificial molds is presented to create customizable, intricate vascular networks inside optical tissue phantoms made of various base materials. This generative design method allows tailoring vascular structures to mimic human tissue variability and complexity, providing a more accurate platform for non‐invasive optical measurements. The Vascular Integrated Tissue Replica Optical – Phantom (VITRO‐P) supports continuous dynamic fluid flow at physiologically relevant rates for over three weeks. Precise flow velocity measurements and beats‐per‐minute (bpm) detection under pulsatile flow are demonstrated, showcasing the platform's versatility. This work sets a new standard for customizable, biomimetic phantoms in biomedical research and clinical testing.