Transition metal ions and their oxide nanoparticles differentially regulate CHO cell growth, metabolism, and N-glycosylation

Trace metal ions act as essential cofactors but exhibit concentration-dependent cytotoxicity that shapes Chinese hamster ovary (CHO) cell culture performance. This work systematically evaluated six transition metal ions (Fe 3+ , Mn 2+ , Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ ) and their metal oxide nanoparticles for their impacts on cell proliferation, metabolism and protein N-glycosylation. Single-metal screening revealed dose-dependent effects: low Fe 3+ and Mn 2+ boosted cell growth, while high Cu 2+ and Zn 2+ triggered severe cytotoxicity. Nanoparticles displayed milder toxicity than ionic metals owing to slow dissolution kinetics. Moderate combined supplementation of Mn 2+ /Fe 3+ ions or as-synthesized layered double hydroxide (LDH) nanoparticles (MnFe-LDH) optimized 14-day batch culture, improving cell viability, protein yield and N-glycan galactosylation. Transcriptomic data identified mitochondrial respiratory chain as the primary responsive pathway, with six subunits of complexes I–V (COX2, COX3, ATP6, ND3, ND4, ND4L) upregulated in a dose-dependent fashion. This study offers mechanistic support for rational trace metal feeding strategies in CHO-based biopharmaceutical production, although practical translation of nanoparticle-based supplementation will additionally require control of particle dissolution behavior and removal of nanoparticle residues during downstream processing.