RGD-Alginate beads as scaffolds for culturing primary human dermal and pulmonary fibroblasts

The use of hydrogel microparticles as granular hydrogels is an emerging approach in tissue engineering, where microparticles offer printability, injectability, and serve as scaffolds for cell culture. While culturing dermal fibroblasts for tissue engineering applications is well reported, there is limited research on culturing primary human pulmonary fibroblasts on granular hydrogels. In this study, we grafted RGD-peptides to alginate, formed microbeads, and investigated the ability of granular hydrogels to support the adhesion and growth of primary normal human dermal fibroblasts (NHDFs) and human pulmonary fibroblasts (HPFa). NHDFs adhered to linear RGD (linRGD)-alginate microbeads and spread on the bead surfaces with increased adhesion with increased peptide concentration (0.3-1.3 mM). In contrast, HPFa did not adhere to the linRGD-alginate microbeads. However, HPFa adhered and spread on flat linRGD-alginate gels, indicating that HPFa do respond to linRGD as an adhesion ligand. Supplementation of Mn²⁺ resulted in cell adhesion to linRGD-alginate microbeads. Enhanced adhesion and spreading of HPFa to RGD-alginate microbeads were observed when using cyclic RGD. Hence, RGD-alginate microbeads is a promising material for structuring primary human dermal and pulmonary fibroblasts, showing the relevance of using alginate microbeads as scaffolds for 3D cultures with fibroblasts.