The long-term behaviors and differences in bone reconstruction of three polymer-based scaffolds with different degradability

J Mater Chem B. 2019 Dec 11;7(48):7690-7703. doi: 10.1039/c9tb02072a.

Abstract

Scaffolds composed of polymers and nano-hydroxyapatite (n-HA) have received extensive attention in bone reconstructive repair; however there is a lack of in-depth and long-term comparative study on the effect of scaffold degradability on bone reconstruction. In this study, the osteogenic behaviors of three polymeric composite scaffolds based on fast degradable poly(lactic-co-glycolic acid) (PLGA), slowly degradable polycaprolactone (PCL) and non-degradable polyamide 66 (PA66) were investigated and compared via implanting the scaffolds into rabbit femoral defects for 1, 3, 6 and 12 months. The in vivo results demonstrated that although the n-HA/PLGA scaffold could obtain higher new bone volume at 3 months, its fast degradation caused the loss of scaffold structural integrity and led to reduction of bone volume after 3 months. The n-HA/PCL scaffold displayed slow degradation mainly after 6 months (∼20% degradation) and the n-HA/PA66 scaffold showed no degradation during the entire 12 months; these two scaffolds could maintain their structural integrity and exhibited a constant increase in bone volume with the implantation time, and even achieved higher bone volume than the n-HA/PLGA scaffold at 12 months. The year-long in vivo research revealed the following important aspects: (1) bone reconstruction is strongly related to scaffold degradability, and the scaffold structural integrity should be maintained at least for one year before complete degradation in vivo; (2) the in vivo experiment of a bone scaffold must take more time than the conventional 3 or 6 months, which is normally neglected. The study suggests a principle for future design and application of bone scaffolds that must have a relatively stable osteogenic space and scaffold interface, or have a scaffold degradation speed slower than the time of bone reconstruction completion.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Regeneration*
  • Durapatite
  • Femur / physiology
  • Nylons / standards
  • Polyesters / standards
  • Polylactic Acid-Polyglycolic Acid Copolymer / standards
  • Rabbits
  • Time Factors
  • Tissue Scaffolds / chemistry
  • Tissue Scaffolds / standards*

Substances

  • Nylons
  • Polyesters
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • polycaprolactone
  • Durapatite