3D-Printed Cell-Instructive Scaffolds Based on <i>Chondrosia reniformis</i> Collagen and Sr-Doped Calcium Phosphates for Bone Tissue Engineering

Bone defects pose a global concern due to their high prevalence. Despite the significant advances in the development of novel therapies and sustainable biomaterial solutions, these still do not perfectly address the clinical needs, in particular, the paradigm shift of personalized treatments. In this sense, marine-origin materials allied to three-dimensional (3D) printing are arising as a feasible alternative to develop innovative personalized approaches, namely, bone tissue engineering (TE). In this study, novel 3D-printed scaffolds composed of collagen obtained from the maricultured marine sponge <i>Chondrosia reniformis</i> and calcium phosphates extracted from codfish (<i>Gadus morhua</i>) bones doped with strontium, and combined with alginate, were developed as a promising approach for bone regeneration. The 3D-printed scaffolds demonstrated suitable pore size and porosity and high interconnectivity, with adequate mechanical properties for bone TE. The <i>in vitro</i> assays conducted with a human osteosarcoma cell line (Saos-2 cells) cultured onto the 3D-printed scaffolds demonstrated a notable improvement in both cell viability and proliferation up to 14 days of culturing. This enhancement was particularly evident in the case of 3D-printed scaffolds containing Sr-doped calcium phosphates. Aligned with the principles of the blue economy and within a sustainable development approach, an innovative 3D-printed scaffold produced from sustainable marine-derived collagen and strontium-doped calcium phosphates with adequate mechanical properties, architecture, and encouraging <i>in vitro</i> performance was developed for bone tissue engineering scaffolding applications.