Mesenchymal stem cells (MSCs) hold significant potential in regenerative medicine, tissue engineering, and cultivated meat production. However, large-scale MSC production is limited by their need for surface adherence during growth. This study evaluates two biocompatible materials—collagen-coated alginate microcarriers and polylactic-co-glycolic acid (PLGA) nanofibers—as novel growth substrates to enhance MSC proliferation. Physicochemical characterization confirmed successful collagen integration on both materials. In vitro, bone marrow-derived MSCs (bmMSCs) cultured on collagen-coated alginate microcarriers exhibited significantly enhanced growth compared to commercial microcarriers, while PLGA nanofibers supported bmMSC growth comparable to traditional growth surfaces. Scanning Electron Microscopy (SEM) revealed that bmMSCs adhered not only to the surface but also grew within the porous structure of the alginate microcarriers. Mycoplasma testing confirmed that the bmMSCs were free from contamination. Both materials were assessed for biocompatibility using ISO-10993 guidelines, demonstrating no skin or ocular irritation, supporting their potential for in situ applications in clinical and therapeutic settings. This study highlights the promise of collagen-coated alginate microcarriers and PLGA nanofibers for scalable MSC production, offering efficient, biocompatible alternatives to traditional growth surfaces in regenerative medicine and cultivated meat manufacturing. Future research should focus on optimizing these materials for larger-scale production and exploring specific applications in therapeutic and food sectors.