Enhancement of osteoblast gene expression by mechanically compatible porous Si-rich nanocomposite

Gautam Gupta, Ahmed El-Ghannam, Sreenatha Kirakodu, Marwan Khraisheh, Hussein Zbib

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29 Citations (Scopus)

Abstract

Synthesis of a porous bioactive ceramic implant for load bearing applications is a challenging task in maxillofacial and orthopedic surgeries. A novel bioactive resorbable silica-calcium phosphate nanocomposite (SCPC) has recently been introduced as a potential bone graft. In the present study, we employed SCPC to develop a resorbable porous scaffold and analyzed the effects of composition and porosity on the mechanical properties. The ranges of compressive strength and modulus of elasticity of SCPC containing 32-56% porosity were 1.5-50 MPa and 0.14-2.1 GPa, respectively, which matched the corresponding values for trabecular bone. The compressive strength of dense SCPC was dependent on the Si content and acquired values (93-285 MPa) comparable to that of cortical bone. The superior mechanical properties of SCPC are attributed to the intricate interactions at the boundaries of the nanograins and to the homogenous distribution of hierarchical pore-structure throughout the material volume. X-ray computed tomography and mercury porosimetry analyses revealed high interconnectivity of the pores in the size range 3 nm to 650 μm. Quantitative real-time PCR analyses showed that neonatal rat calvarial osteoblasts attached to Si-rich SCPC expressed 5- and 26-fold higher osteocalcin mRNA levels compared to cells attached to ProOsteon™ hydroxyapatite disks and tissue culture polystyrene plates respectively, after four days in culture. Results of the present study strongly suggest that porous, bioactive resorbable SCPCs can serve as tissue engineering scaffolds for cell delivery to treat load-bearing bone defects in orthopedic and maxillofacial surgeries.

Original languageEnglish
Pages (from-to)387-396
Number of pages10
JournalJournal of Biomedical Materials Research - Part B Applied Biomaterials
Volume81
Issue number2
DOIs
Publication statusPublished - 1 May 2007

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Keywords

  • Mechanical properties
  • Osteoblast gene expression
  • Porous nanocomposites
  • Tissue engineering
  • X-ray tomography

ASJC Scopus subject areas

  • Biomaterials
  • Biomedical Engineering

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