A new printable and durable N,O-carboxymethyl chitosan–Ca2+–polyphosphate complex with morphogenetic activity

Biomimetic materials have been gaining increasing importance in tissue engineering since they may provide regenerative alternatives to the use of autologous tissues for transplantation. In the present study, we applied for bioprinting of a functionalized three-dimensional template, N,O-carboxymethyl chitosan (N,O-CMC), mimicking the physiological extracellular matrix. This polymer, widely used in tissue engineering, has been provided with functional activity by integration of polyphosphate (polyP), an osteogenically acting natural polymer. The two polymers, N,O-CMC and polyP, are linked together via Ca2+ bridges. This N,O-CMC + polyP material was proven to be printable and durable. The N,O-CMC + polyP printed layers and tissue units retain their properties to induce SaOS-2 bone-like cells to biomineralization. Subsequent in vivo experiments revealed a strong regeneration-inducing activity of the material in the rat calvarial defect model. In turn, N,O-CMC + polyP represents a promising hybrid material useful as a potential custom-designed scaffold for alternative tissue-engineering solutions.