Microfluidic Biofabrication of a Hydrogel Vessel-Like Structure for Interrogating Tumor Cell Propagation in a Breast...

Engineering physiologically relevant vascular models remains a challenge in cancer biology and tissue engineering. Here, we present a microfluidic wet-spinning methodology for the biofabrication of cell-laden alginate-gelatin methacryloyl (GelMA) hydrogel-based vessel-like structures with controlled geometry and perfusable architecture. Using a sacrificial gelatin core within a core-shell microfluidic device, tubular scaffolds were produced in a single continuous step under mild, cell-compatible conditions. The alginate-GelMA shell is fine-tuned and loaded with human umbilical vein endothelial cells (HUVEC), yielding an endothelialized-like, perfusable construct at the small-vein scale (∼0.6-0.7 mm lumen diameter). As a proof-of-concept use case, the biofabricated vessel-like structure was integrated into the breast cancer-on-a-chip (BCoC) platform to showcase its feasibility in a 3D vascularized-like tumor model for interrogating cancer cell propagation. Breast cancer spheroids were positioned in the surrounding GelMA matrix (perivascular-like compartment), and THP-1 monocytes were circulated through the perfusion platform. Cancer cell dissemination, quantified as circulating tumor cells (CTCs), was modulated by the immune microenvironment: interleukin-4 (IL-4, anti-inflammatory-like) conditions promoted peak CTC release, whereas lipopolysaccharide (LPS, pro-inflammatory-like) stimulation suppressed this dissemination. Our model integrates the vascular, tumor, and immune compartments within a single construct, providing a versatile platform for investigations of breast cancer dissemination and tumor-immune crosstalk.