Hybrid PCL/CaCO3 scaffolds with capabilities of carrying biologically active molecules: Synthesis, loading and in vivo applications

Highlights: • The new tissue engineering polycaprolactone/CaCO₃ scaffolds enhanced with drug delivery function were designed. • CaCO₃ coating of polymeric scaffold induced intensive cells colonization and vascularization in implantation area of rats. • Loading of polymeric/CaCO₃ scaffold with tannic acid improved stabilization of blood vessels in the area of implantation. - Abstract: Designing advanced biomaterials for tissue regeneration with drug delivery and release functionalities remains a challenge in regenerative medicine. In this research, we have developed novel composite scaffolds based on polymeric polycaprolactone fibers coated with porous calcium carbonate structures (PCL/CaCO₃) for tissue engineering and have shown their drug delivery and release in rats. In vivo biocompatibility tests of PCL/CaCO₃ scaffolds were complemented with in vivo drug release study, where tannic acid (TA) was used as a model drug. Release of TA from the scaffolds was realized by recrystallization of the porous vaterite phase of calcium carbonate into the crystalline calcite. Cell colonization and tissue vascularization as well as transplantability of developed PCL/CaCO₃ + TA scaffolds were observed. Detailed study of scaffold transformations during 21-day implantation period was followed by scanning electron microscopy and X-ray diffraction studies before and after in vivo implantation. The presented results demonstrate that PCL/CaCO₃ scaffolds are attractive candidates for implants in bone regeneration and tissue engineering with a possibility of loading biologically active molecules and controlled release.