Sr2+ vs. Ca2+ as post-processing ionic crosslinkers: implications for 3D bioprinting of polysaccharide hydrogels in tissue engineering

Among the possible ionic crosslinkers Ca2+ is most widely used. However, due to its numerous physiological functions, other cations such as Sr2+ may be more suitable depending on application. Because a systematic comparison currently lacking, this work aims compare solutions of CaCl2 and SrCl2 alginate- cellulose-based materials investigate their effects structural biological properties 3D bioprinted scaffolds. In particular, swelling degradation under cell culture conditions, mechanical (with quasi-static compression tests), surface topology scanning electron microscopy atomic force microscopy) elemental composition were investigated. addition, cytotoxicity pancreatic islet cells was assessed by measuring viability, metabolic activity morphology. The obtained results show that Sr2+-crosslinked scaffolds have higher compressive strength, swell faster degrade slowly conditions rougher surface. Both crosslinking agents gentle cells, either when directly embedded into or in contact with scaffold extracts, allowed stable for 30 days. elicited activity. Overall, are viable alternative allow expanding range adjusting concentration ratio mixed solution.