title: Tunability of collagen matrix mechanical properties via multiple modes of mineralization.
abstract: Functionally graded, mineralized collagen tissues exist at soft-to-hard material attachments throughout the body. However, the details of how collagen and hydroxyapatite mineral (HA) interact are not fully understood, hampering efforts to develop tissue-engineered constructs that can assist with repair of injuries at the attachments of soft tissues to bone. In this study, spatial control of mineralization was achieved in collagen matrices using simulated body fluids (SBFs). Based upon previous observations of poor bonding between reconstituted collagen and HA deposited using SBF, we hypothesized that mineralizing collagen in the presence of fetuin (which inhibits surface mineralization) would lead to more mineral deposition within the scaffold and therefore a greater increase in stiffness and toughness compared with collagen mineralized without fetuin. We tested this hypothesis through integrated synthesis, mechanical testing and modelling of graded, mineralized reconstituted collagen constructs. Results supported the hypothesis, and further suggested that mineralization on the interior of reconstituted collagen constructs, as promoted by fetuin, led to superior bonding between HA and collagen. The results provide us guidance for the development of mineralized collagen scaffolds, with implications for bone and tendon-to-bone tissue engineering.
authors: Department of Orthopaedic Surgery , Washington University , St Louis, MO 63130 , USA.
authors: Lester J
authors: LJ
authors: Smith
authors: Department of Orthopaedic Surgery , Washington University , St Louis, MO 63130 , USA.
authors: Alix C
authors: AC
authors: Deymier
authors: Department of Orthopaedic Surgery, Washington University, St Louis, MO 63130, USA; Department of Biomedical Engineering, Washington University, St Louis, MO 63130, USA.
authors: John J
authors: JJ
authors: Boyle
authors: Department of Earth and Planetary Sciences , Washington University , St Louis, MO 63130 , USA.
authors: Zhen
authors: Z
authors: Li
authors: Department of Orthopaedic Surgery, Washington University, St Louis, MO 63130, USA; Department of Biomedical Engineering, Washington University, St Louis, MO 63130, USA.
authors: Stephen W
authors: SW
authors: Linderman
authors: Department of Earth and Planetary Sciences , Washington University , St Louis, MO 63130 , USA.
authors: Jill D
authors: JD
authors: Pasteris
authors: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors: Younan
authors: Y
authors: Xia
authors: Department of Mechanical Engineering and Materials Science , Washington University , St Louis, MO 63130 , USA.
authors: Guy M
authors: GM
authors: Genin
authors: Department of Orthopedic Surgery, Columbia University, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10032, USA.
authors: Stavros
authors: S
authors: Thomopoulos
keywords: biomineralization; functional grading; homogenization; hydroxyapatite; multiscale modelling; tissue engineering