title: Porous titanium bases for osteochondral tissue engineering.
abstract: Tissue engineering of osteochondral grafts may offer a cell-based alternative to native allografts, which are in short supply. Previous studies promote the fabrication of grafts consisting of a viable cell-seeded hydrogel integrated atop a porous, bone-like metal. Advantages of the manufacturing process have led to the evaluation of porous titanium as the bone-like base material. Here, porous titanium was shown to support the growth of cartilage to produce native levels of Young's modulus, using a clinically relevant cell source. Mechanical and biochemical properties were similar or higher for the osteochondral constructs compared to chondral-only controls. Further investigation into the mechanical influence of the base on the composite material suggests that underlying pores may decrease interstitial fluid pressurization and applied strains, which may be overcome by alterations to the base structure. Future studies aim to optimize titanium-based tissue engineered osteochondral constructs to best match the structural architecture and strength of native grafts.
  
  
  CONCLUSIONS
  The studies described in this manuscript follow up on previous studies from our lab pertaining to the fabrication of osteochondral grafts that consist of a bone-like porous metal and a chondrocyte-seeded hydrogel. Here, tissue engineered osteochondral grafts were cultured to native stiffness using adult chondrocytes, a clinically relevant cell source, and a porous titanium base, a material currently used in clinical implants. This porous titanium is manufactured via selective laser melting, offering the advantages of precise control over shape, pore size, and orientation. Additionally, this manuscript describes the mechanical influence of the porous base, which may have applicability to porous bases derived from other materials.
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA. Electronic address: abn2106@columbia.edu.
authors: Adam B
authors: AB
authors: Nover
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA. Electronic address: sll2164@columbia.edu.
authors: Stephanie L
authors: SL
authors: Lee
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA. Electronic address: sinzigeorgescu@gmail.com.
authors: Maria S
authors: MS
authors: Georgescu
authors: Department of Orthopedic Surgery, Mt. Sinai St. Luke's-Roosevelt Hospital, 1000 Tenth Avenue, New York, NY 10019, USA. Electronic address: danhoward@chpnet.org.
authors: Daniel R
authors: DR
authors: Howard
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA. Electronic address: reubens@mit.edu.
authors: Reuben A
authors: RA
authors: Saunders
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA. Electronic address: wty2102@columbia.edu.
authors: William T
authors: WT
authors: Yu
authors: Stryker Orthopaedics, 325 Corporate Drive, Mahwah, NJ 07430, USA. Electronic address: Robert.Klein@stryker.com.
authors: Robert W
authors: RW
authors: Klein
authors: Stryker Orthopaedics, 325 Corporate Drive, Mahwah, NJ 07430, USA. Electronic address: Napolitano@plymouthcma.com.
authors: Anthony P
authors: AP
authors: Napolitano
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA; Department of Mechanical Engineering, Columbia University, 242 S. W. Mudd, 500 West 120th Street, Mail Code: 4703, New York, NY 10027, USA. Electronic address: ateshian@columbia.edu.
authors: Gerard A
authors: GA
authors: Ateshian
authors: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027, USA. Electronic address: cth6@columbia.edu.
authors: Clark T
authors: CT
authors: Hung
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry*; D002358:Cartilage, Articular / Q000166:cytology / Q000254:growth & development*; D049109:Cell Proliferation / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000502:physiology*; D019245:Compressive Strength; D004285:Dogs; D055119:Elastic Modulus; D016062:Porosity; D013314:Stress, Mechanical; D013718:Tensile Strength; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods; D054457:Tissue Scaffolds; D014025:Titanium / Q000737:chemistry*
chemical_list: D018786:Bone Substitutes; D014025:Titanium
keywords: Articular cartilage; Osteochondral grafts; Porous titanium; Tissue engineering