Novel lactone-layered double hydroxide ionomer powders for bone tissue repair

This article describes the use of a novel lactone-layered double hydroxide polymer network (PN), derived from a poly(lactide-co-caprolactone) copolymer, as a controlled ion-release agent for artificial bone tissue regeneration. The osteogenic cell culture Saos-2 is used as a test culture to investigate the PN's performance as an extracellular ion-release agent. The compelling performance of this PN is demonstrated in both growth and osteogenic media compared with a control of cells grown on tissue culture plastic (TCP) without PN. Firstly, the PNs released concentration of magnesium ions over time ranging from 10 to 60 mM after 24 hr, depending on the PN sample. After incubation of Saos-2 with the PN, while no difference was seen in cell number, there was significant upregulation of bone-related gene expression at 14 days-~5fold increase in Bone Morphogenetic Protein 2, ~3fold increase in osteopontin and ~2fold increase in collagen Type I. In addition, normalized alkaline phosphatase activity was seen to significantly increase by ~2fold with PN presence. A ~4fold increase in collagen Type I protein expression (via Gomori Trichrome Stain) was observed with PN presence. In addition, a ~4fold increase in phosphate deposits (as seen with Von Kossa staining analysis) was seen with PN presence. It is found that this novel PN material has a significant potential for bone tissue regeneration.