Structural changes to resorbable calcium phosphate bioceramic aged in vitro

•Porous 3D printed bone-like calcium phosphate scaffolds.•Effect of in vitro immersion on scaffold degradation is investigated.•Dissolution in surrounding medium results in structural changes.•High sera protein concentrations lead to the development of sub-micron pores.•Tenocyte seeding inhibited increases in scaffold porosity. This work investigates the effect of mammalian cell culture conditions on 3D printed calcium phosphate scaffolds. The purpose of the studies presented was to characterise the changes in scaffold properties in physiologically relevant conditions. Differences in crystal morphologies were observed between foetal bovine serum-supplemented media and their unsupplemented analogues, but not for supplemented media containing tenocytes. Scaffold porosity was found to increase for all conditions studied, except for tenocyte-seeded scaffolds. The presence of tenocytes on the scaffold surface inhibited any increase in scaffold porosity in the presence of extracellular matrix secreted by the tenocytes. For acellular conditions the presence or absence of sera proteins strongly affected the rate of dissolution and the distribution of pore diameters within the scaffold. Exposure to high sera protein concentrations led to the development of significant numbers of sub-micron pores, which was otherwise not observed. The implication of these results for cell culture research employing calcium phosphate scaffolds is discussed.