Methodological innovations in perfusable vascular networks: Advancing high-density tissue models.

Area of Science:

• Biomedical Engineering
• Tissue Engineering
• Vascular Biology

Background:

• Physiologically relevant in vitro tissue models are limited by the lack of perfusable vasculature.
• Low-density (LD) tissues rely on diffusion, overestimating drug penetration and missing metabolic gradients.
• High-density (HD) tissues mimic in vivo conditions but require vascularization to prevent necrosis.

Purpose of the Study:

• To review methodological innovations for creating perfusable vasculature in engineered tissues.
• To explore the functional consequences of vascularization in high-density tissue models.
• To highlight the potential of vascularized HD tissues as next-generation translational models.

Main Methods:

• Endothelial cell-based strategies (self-assembly, angiogenesis, co-culture).
• Microfluidic platforms for patterned conduits and angiogenesis studies.
• Bioprinting and sacrificial templating for scalable networks.
• Synthetic microvascular scaffolds (e.g., two-photon polymerization).
• Hybrid approaches integrating organoids, bioprinting, and microfluidics.

Main Results:

• Vascularization sustains metabolic activity and tissue-specific phenotypes in HD tissues.
• Vascularized HD tumor models replicate drug gradients, angiogenesis, and invasion.
• Vascularized liver and cardiac tissues enable accurate toxicity prediction and pharmacokinetic studies.
• Perfusion facilitates dynamic cell delivery, enabling modeling of immune infiltration and metastatic spread.

Conclusions:

• Vascularized HD tissues bridge the gap between in vitro models and in vivo physiology.
• These models enhance drug safety prediction, immunotherapy testing, and therapeutic development.
• Immune-integrated vascularized systems represent a frontier for modeling complex biological processes.