Journal of Materials Research

Articles

Bioinspired synthesis of self-assembled calcium phosphate nanocomposites using block copolymer-peptide conjugates

Yusuf Yusufoglua1a), Yanyan Hua1a), Mathumai Kanapathipillaia1, Matthew Kramera1, Yunus E. Kalaya1, P. Thiyagarajana2, Mufit Akinca3, Klaus Schmidt-Rohra3 and Surya Mallapragadaa3 c1

a1 Ames Laboratory, Ames, Iowa 50011

a2 Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439

a3 Ames Laboratory, Ames, Iowa 50011

Abstract

Thermoreversibly gelling block copolymers conjugated to hydroxyapatite-nucleating peptides were used to template the growth of inorganic calcium phosphate in aqueous solutions. Nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), transmission electron microscopy, x-ray diffraction, and small-angle scattering were used to characterize these samples and confirm that the peptides promoted the growth of hydroxyapatite as the inorganic phase. Three different polymer templates were used with varying charges on the polymer chains (nonionic, anionic, and zwitterionic), to investigate the role of charge on mineralization. All of the polymer-inorganic solutions exhibited thermoreversible gelation above room temperature. Nanocomposite formation was confirmed by solid-state NMR, and several methods identified the inorganic component as hydroxyapatite. Small angle x-ray scattering and electron microscopy showed thin, elongated crystallites. Thermogravimetric analysis showed an inorganic content of 30–45 wt% (based on the mass of the dried gel at ∼200 °C) in the various samples. Our work offers routes for bioinspired bottom-up approaches for the development of novel, self-assembling, injectable nanocomposite biomaterials for potential orthopedic applications.

(Received April 29 2008)

(Accepted August 18 2008)

Key Words:

  • Biomimetic (assembly);
  • Nanostructure;
  • Self-assembly

Correspondence:

c1 Address all correspondence to this author. suryakm@iastate.edu

Footnotes

a) These authors contributed equally to this work.

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