Lian, Xiaojun Lance

Introduction Large-scale production of mammalian cells is pivotal for applications in biotechnology, regenerative medicine, and therapeutic manufacturing. However, current bioreactor technologies face significant technical and economic challenges, including excessive cell aggregation, shear stress-induced cell death, batch-to-batch inconsistencies, and limited scalability. We propose that engineering a cell-friendly microenvironment can enhance culture efficiency. Previously, we developed alginate hydrogel microtubes (AlgTubes) that significantly improved cell density and growth rates; however, AlgTubes lack adhesion sites essential for anchorage-dependent cells and frequently break, causing cell leakage and production inconsistencies. Methods To address these limitations, we reinforced AlgTubes with collagen nanofibers, creating collagen-alginate hybrid hydrogel microtubes (ColAlgTubes). Collagen was integrated to form a dense nanofiber network interwoven with the alginate mesh, with the dual aim of enhancing mechanical properties and providing cell adhesion sites. ColAlgTubes were fabricated to maintain cell mass within a 400 μm diameter to ensure efficient nutrient exchange and waste removal. Results ColAlgTubes successfully formed a reinforced hybrid hydrogel structure in which the collagen nanofiber network improved the mechanical integrity of the alginate matrix while supplying adhesion sites for anchorage-dependent cells. The optimized 400 μm diameter microenvironment supported high cell viability, rapid proliferation, and exceptional yields of 5 × 10 8 cells/mL. Discussion These results demonstrate that ColAlgTubes overcome the key limitations of AlgTubes by combining structural reinforcement with biological functionality. The improved mechanical properties reduce tube breakage and cell leakage, while collagen-derived adhesion sites broaden compatibility to anchorage-dependent cell types. With their scalability, cost-effectiveness, and high efficiency, ColAlgTubes represent a transformative solution for large-scale mammalian cell production across biotechnology, regenerative medicine, and therapeutic manufacturing.

AbstractProper cell‐cycle progression is essential for the self‐renewal and differentiation of human pluripotent stem cells (hPSCs). The fluorescent ubiquitination‐based cell‐cycle indicator (FUCCI) has allowed the dual‐color visualization of the G1 and S/G2/M phases in various dynamic models, but its application in hPSCs is not widely reported. In addition, lineage‐specific FUCCI reporters have not yet been developed to analyze complex tissue‐specific cell‐cycle progression during hPSC differentiation. Desiring a robust tool for spatiotemporal reporting of cell‐cycle events in hPSCs, we employed the CRISPR/Cas9 genome editing tool and successfully knocked the FUCCI reporter into the AAVS1 safe harbor locus of hPSCs for stable and constitutive FUCCI expression, exhibiting reliable cell‐cycle‐dependent fluorescence in both hPSCs and their differentiated progeny. We also established a cardiac‐specific TNNT2‐FUCCI reporter for lineage‐specific cell‐cycle monitoring of cardiomyocyte differentiation from hPSCs. This powerful and modular FUCCI system should provide numerous opportunities for studying human cell‐cycle activity, and enable the identification and investigation of novel regulators for adult tissue regeneration.