Effect of Collagen in Calcium Phosphate Cement on Mechanical and Cellular Properties

Published

December 23, 2008

Author(s)

Jennifer L. Moreau, Michael Weir, Hockin D. Xu

Abstract

Calcium phosphate cement (CPC) can be molded to conform to complex bone cavities and set in situ to form bioresorbable hydroxyapatite. The aim of this study was to develop a biomimetic nano apatite-collagen fiber composite, and to investigate the effect of collagen on mechanical and cellular properties. A type I bovine collagen powder (Sigma Aldrich) was added to CPC to develop a bone-mimicking, nano apatite-collagen composite. Work-of-fracture (toughness), measured in three-point flexure (mean sd; n = 6), was increased from (9.4 3.1) J/m2 for CPC with 0 % collagen, to (430 103) J/m2 for CPC containing 4.05 % collagen (p < 0.05), at a CPC powder to liquid (P/L) ratio of 2.5. At P/L = 3, work-of-fracture was increased from (22.2 3.8) J/m2 without collagen, to (381 119) J/m2 with 4.05 % collagen (p < 0.05). At P/L of 3 and 2.5, collagen volume fraction had no significant effect on the CPC flexural strength (p > 0.1); at P/L = 3.5, collagen incorporation slightly decreased the flexural strength.SEM examination revealed coverage of collagen fibers by nano apatite crystals with intimate contact between the two. Increasing the collagen volume fraction in CPC significantly increased the number of MC3T3-E1 osteoblast cell attachment (p < 0.05). The number of live cells/specimen area was (382 99) per mm2 on CPC containing 4.05 % collagen, significantly higher than (173 42) at 0 % collagen (p < 0.05). Cells on the CPC-collagen composite exhibited a healthy polygonal and spread morphology, with cytoplasmic extensions firmly anchoring to the nano apatite crystals. In summary, collagen fibers were incorporated into a nano apatitic CPC for the first time, which substantially increased the work-of-fracture of the cement. The number of cells attached to the CPC-collagen composite was more than doubled, comparing to that without collagen. Hence the moldable nano apatite-collagen composite may be useful in bone tissue engineering in moderate stress-bearing applications

Citation

Biomaterials

Volume

91A

Pub Type

Journals

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Keywords

bone tissue engineering, cell attachment, collagen fibers, live cell density, phosphate cement, strength, work-of-fracture, Dentistry

Citation

Moreau, J. , Weir, M. and Xu, H. (2008), Effect of Collagen in Calcium Phosphate Cement on Mechanical and Cellular Properties, Biomaterials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852748 (Accessed December 12, 2024)