Biomimetic study of a polymeric composite material for joint repair applications
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Poulomi Ganguly and Donald Darensbourg Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012
Meitin Usta Gebze Institute of Technology, Department of Materials Science and Engineering, 41400 Gebze/Kocaeli, Turkey
A. Hikmet Ucisik Bogazici University, Institute of Biomedical Engineering, Department of Prostheses, Materials and Artificial Organs, 80815 Bebek/Istanbul, Turkey
Hong Lianga) Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843 (Received 21 December 2005; accepted 26 February 2007)
A longer lifespan is still being sought for biomaterials used for joint repair. We developed a new nanocomposite material of polytrimethylene carbonate (PTMC), hydroxyapatite (HAP), and multiwalled carbon nanotubes (MWNT) to mimic real cartilage. Experimental results were compared with those of natural cartilage and the conventional joint replacement material ultrahigh-molecular-weight polyethylene (UHMWPE). Friction experiments showed that our developed composite material had a coefficient of friction close to that of articular cartilage. Nanoindentation experiments indicated that the surface elastic behavior was similar to that of cartilage. The surface attraction forces on a silicon atomic force microscope tip were much higher for cartilage than those for the other two materials. These results hold promise for this artificial cartilage composite material’s performance in vivo, following further experimental investigations and chemical modifications.
I. INTRODUCTION
Bone joints in the human body are covered with a layer of articular cartilage. The bones on either side of the joint do not come into direct contact and are connected by ligaments. The cartilage surfaces are lubricated by synovial fluid, and the resulting coefficient of friction rendered is on the order 0.01.1 Articular cartilage is sometimes subject to degradation due to injury or illness.2 Because it is avascular, cartilage does not have a healing capacity. Total joint replacement (TJR) has been the primary method of treating such degradation.3 In this method, part of the joint on either side (which includes the cartilage and subchondral bone) is removed by surgery. In its place, an artificial prosthesis is implanted into the marrow cavity of long bones and into a reamed cavity in other bones (e.g., the pelvis for the hip joint). Over a
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Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2007.0204 1632 J. Mater. Res., Vol. 22, No. 6, Jun 2007 http://journals.cambridge.org Downloaded: 13 Mar 2015
million total joint replacements of the hip itself are conducted worldwide every year.4 In the 1960s, Sir John Charnley invented a TJR, which is in widespread use even today.5 The life span of TJRs is limited to 10–15 years due to mechanical wear.6 This poses a problem for younger patients, and currently 11% of people who receive hip implants are under 40 years old.7 Osteolysis and aseptic loosening is the primary reason for failure of TJRs.7 Particles released from th
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