Alginate-Coated Collagen Hydrogel Tubes for Scalable Cell and Biotherapeutic Particle Manufacturing

Efficient, scalable, and cost-effective production of mammalian cells and biotherapeutic particles remains a major challenge for both research and clinical applications. Conventional 2D and 3D culture systems suffer from low volumetric yields, poor scalability, and high costs. Previously, we developed collagen hydrogel tube microbioreactors (ColTubes) that support high-density, high-viability cell culture by preventing excessive cell aggregation and minimizing hydrodynamic stress. However, ColTubes exhibit adhesion to culture vessels and to each other, and leaked cells frequently attach to outer tube surfaces -- behaviors that would limit scalability. Here we introduce AlgColTubes: collagen hydrogel tubes coated with a thin, ionically crosslinked alginate layer to overcome these limitations. Scanning electron microscopy confirms that alginate penetrates the collagen wall and forms a stable interpenetrating hydrogel network, whose depth can be tuned by coating concentration and duration. The alginate coating remains structurally intact under static and dynamic culture conditions without impairing nutrient transport or cell growth. AlgColTubes eliminate tube-tube and tube-vessel adhesion, and prevent exogenous cell attachment to the outer surface, while maintaining cell viability and proliferation comparable to uncoated ColTubes. Their unique architecture -- an adhesive collagen interior and non-adhesive alginate exterior -- further enables a truncated-tube format for continuous release of biotherapeutic particles through open tube ends. We demonstrate that lentivirus is released from truncated AlgColTubes in a segment length-dependent manner, reaching ~100% release efficiency at 1-mm segment lengths. AlgColTubes provide a scalable, cost-effective platform for high-yield cell and particle manufacturing, with broad potential across basic research, translational studies, and industrial bioprocessing.