title: Critical factors in the design of growth factor releasing scaffolds for cartilage tissue engineering.
abstract: BACKGROUND
  Trauma or degenerative diseases of the joints are common clinical problems resulting in high morbidity. Although various orthopedic treatments have been developed and evaluated, the low repair capacities of articular cartilage renders functional results unsatisfactory in the long term. Over the last decade, a different approach (tissue engineering) has emerged that aims not only to repair impaired cartilage, but also to fully regenerate it, by combining cells, biomaterials mimicking extracellular matrix (scaffolds) and regulatory signals. The latter is of high importance as growth factors have the potency to induce, support or enhance the growth and differentiation of various cell types towards the chondrogenic lineage. Therefore, the controlled release of different growth factors from scaffolds appears to have great potential to orchestrate tissue repair effectively.
  
  
  OBJECTIVE
  This review aims to highlight considerations and limitations of the design, materials and processing methods available to create scaffolds, in relation to the suitability to incorporate and release growth factors in a safe and defined manner. Furthermore, the current state of the art of signalling molecules release from scaffolds and the impact on cartilage regeneration in vitro and in vivo is reported and critically discussed.
  
  
  METHODS
  The strict aspects of biomaterials, scaffolds and growth factor release from scaffolds for cartilage tissue engineering applications are considered.
  
  
  CONCLUSIONS
  Engineering defined scaffolds that deliver growth factors in a controlled way is a task seldom attained. If growth factor delivery appears to be beneficial overall, the optimal delivery conditions for cartilage reconstruction should be more thoroughly investigated.
authors.affiliation: Laboratory for osteo-articular and dental tissue engineering (LIOAD), Faculté de chirurgie dentaire de Nantes, Inserm U791, 1 Place Alexis Ricordeau, 44042 Nantes Cedex 1, France. jerome.sohier@univ-nantes.fr
authors.forename: J
authors.initials: J
authors.lastname: Sohier
authors.forename: L
authors.initials: L
authors.lastname: Moroni
authors.forename: C
authors.initials: C
authors.lastname: van Blitterswijk
authors.forename: K
authors.initials: K
authors.lastname: de Groot
authors.forename: J M
authors.initials: JM
authors.lastname: Bezemer
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002356:Cartilage / Q000502:physiology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000008:administration & dosage / Q000494:pharmacology; D011108:Polymers; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D036341:Intercellular Signaling Peptides and Proteins; D011108:Polymers