Development and comparison of two 3D printed scaffolds of biosilica from marine sponges for bone tissue engineering

This study compared the physicochemical characteristics and biological effects of two 3D printed biosilica (BS) scaffolds (grid and gyroid). Methods included Scanning Electron Microscopy (SEM), Micro-Computed Tomography (Micro-CT), Mass Loss and pH Assessment, Fourier-Transform Infrared Spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS). The mechanical evaluation involved a Compression Test, and in vitro tests used cell adhesion assays with osteoblastic (MC3T3-E1) and fibroblastic (L929) cell lines. SEM showed BS spicules in both models on day 0, with signs of degradation along the experimental periods of immersion, forming a homogeneous network with the interaction with alginate. Micro-CT revealed rough surfaces in both models, with the gyroid model being more homogeneous and porous, with larger pores compared to the grid model. The gyroid model demonstrated higher values in the compression test and a decrease in pH on the first day and no differences for both models on days 3, 7, and 14. The mass loss was higher in the gyroid model by day 21. FTIR tests showed characteristic peaks for ALG and BS. EDS detected silica (Si), chlorine (Cl), calcium (Ca), carbon (C), and oxygen (O). In cell adhesion assays, both models supported adhesion and proliferation of L929 and MC3T3-E1 cells, with the gyroid model showing better cell elongation and morphology. Overall, the gyroid model demonstrated superior physicochemical properties, greater mechanical strength, and enhanced biological performance compared to the grid model, making it more promising for tissue engineering applications.