Objective: Articular cartilage lesions represent a major clinical challenge due to limited regenerative capacity, particularly in osteoarthritis (OA), and tissue engineering approaches combining a range of biomaterials, cells and growth factors may offer promising alternatives. Hydrogels, by mimicking the extracellular matrix (ECM), may influence cell behavior. Therefore, we aimed to evaluate whether injectable and bioprintable hydrogels contribute differently to the in vitro chondrogenic differentiation of human adipose-derived stromal cells (hASCs).

Materials and Methods: Two commercial hydrogels functionalized with arginine–glycine–aspartic acid (RGD) motifs, VG-RGD (injectable) and VINK-RGD (bioprintable) were evaluated using human adipose-derived stromal cells. Rheological and mechanical properties, printability, and cytocompatibility were assessed. Printing parameters were chosen to print 3D cell-embedded construct (Discovery 3D, RegenHu) with interconnected pores to guarantee nutrient permeability using extrusion technology. Chondrogenic differentiation was evaluated at multiple time points (day 2, 10, 28) via real-time PCR, immunohistochemistry, transmission electron microscopy (TEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR).

Results: ATR-FTIR showed that RGD-functionalized hydrogels exhibit the characteristic bands of sodium alginate. Rheological analysis revealed shear-thinning behavior in both VG-RGD and VINK-RGD, with stiffness range from 1.30 to 3.66 kPa, respectively. VINK-RGD exhibited superior shear-thinning behavior and structural fidelity post-printing. Both hydrogels effectively supported hASC viability and did not show cytotoxic effects. VG-RGD and VINK-RGD supported the expression of key chondrogenic markers COL2A1, SOX9 and ACAN, which significantly increased over time, while COL1A1 expression decreased in VINK-RGD by day 28. ATR-FTIR confirmed the formation of collagen type II in both hydrogels, while TEM revealed more organized fibrillar collagen structures in VG-RGD.

Conclusions: VG-RGD and VINK-RGD hydrogels both effectively support chondrogenic differentiation and extracellular matrix remodeling. This study provides the first direct comparison of injectable and bioprintable RGD-modified hydrogels under identical cell and culture conditions, offering critical insights for the rationale selection of materials in cartilage tissue engineering.