Investigation of Fabrication and Environmental Effects on Bioceramic Bone Scaffolds

Bioactive ceramic materials like tricalcium phosphates (TCP) have been emerging as viable material alternatives to the current therapies of bone scaffolding to target fracture healing and osteoporosis. Once scaffolds are implanted at the defect site they should provide mechanical and biological functions, ultimately serving to facilitate with surrounding native tissue. Optimal osteogenic signal expression and subsequent differentiation of cells seeded on the scaffold in both in vivo and in vitro conditions is known to be influenced by scaffold properties and biomechanical environmental conditions. Thus, the objective of this research was to investigate the effect of fabrication and environmental variables on the properties of bioceramic scaffolds for bone tissue engineering applications. Specifically, the effect of sintering temperature in the range of 950°C -1150°C of a cost-effective on a large scale manufacturing process, on the physical and mechanical properties of bioceramic bone scaffolds, was investigated. In addition, the effect of a controlled environment was investigated by implementing a bioreactor and bone loading system to study the response of ex vivo trabecular bone to compressive load while perfused with culture medium. Collectively, this thesis demonstrates that: (1) the sintering temperature to fabricate bioceramic scaffolds can be tuned to structural properties, and (2) the use of a controlled mechanical and biochemical environment can enhance bone tissue development. These findings support the development of clinically successful bioceramic scaffolds that may stimulate bone regeneration and scaffold integration while providing structural integrity.

Year	Entry
1993	Lanyon LE. Osteocytes, strain detection, bone modeling and remodeling. Calcif Tiss Int. February 1993;53(suppl 1):S102-S107.
2008	Lewis G, Nyman JS. The use of nanoindentation for characterizing the properties of mineralized hard tissues: state-of-the art review. J Biomed Mater Res. October 2008;B87(1):286-301.
2000	Brown TD. Techniques for mechanical stimulation of cells in vitro: a review. J Biomech. January 2000;33(1):3-14.
1999	Rho J-Y, Pharr GM. Effects of drying on the mechanical properties of bovine femur measured by nanoindentation. J Mater Sci Mater Med. 1999;10(8):485-488.
1987	Frost HM. The mechanostat: a proposed pathogenic mechanism of osteoporoses and the bone mass effects of mechanical and nonmechanical agents. Bone Miner. April 1987;2(2):73-85.
1997	Smalt R, Mitchell FT, Howard RL, Chambers TJ. Induction of NO and prostaglandin E₂ in osteoblasts by wall-shear stress but not mechanical strain. Am J Physiol Endocrinol Metab. October 1997;273(4):E751-E758.
2004	Mullender M, El Haj AJ, Yang Y, van Duin MA, Burger EH, Klein-Nulend J. Mechanotransduction of bone cells in vitro: mechanobiology of bone tissue. Med Biol Eng Comput. January 2004;42(1):14-21.
2003	Steck R, Niederer P, Knothe Tate ML. A finite element analysis for the prediction of load-induced fluid flow and mechanochemical transduction in bone. J Theo Biol. January 21, 2003;220(2):249-259.
1997	Keaveny TM, Pinilla TP, Crawford RP, Kopperdahl DL, Lou A. Systematic and random errors in compression testing of trabecular bone [published correction appears in J Orthop Res. 1995;17(1):151]. J Orthop Res. 1997;15(1):101-110.
2003	Cartmell SH, Porter BD, García AJ, Guldberg RE. Effects of medium perfusion rate on cell-seeded three-dimensional bone constructs in vitro. Tissue Eng. December 2003;9(6):1197-1203.
2004	Knothe Tate ML, Adamson JR, Tami AE, Bauer TW. The osteocyte. Int J Biochem Cell Biol. January 2004;36(1):1-8.
2001	Keaveny TM, Morgan EF, Niebur GL, Yeh OC. Biomechanics of trabecular bone. Annu Rev Biomed Eng. 2001;3:307-333.
1998	Martin RB, Burr DB, Sharkey NA. Skeletal Tissue Mechanics. New York, NY: Springer-Verlag; 1998.
2000	Knothe Tate ML, Steck R, Forwood MR, Niederer P. In vivo demonstration of load-induced fluid flow in the rat tibia and its potential implications for processes associated with functional adaptation. J Exp Biol. September 2000;203(18):2737-2745.
2005	McGarry JG, Klein-Nulend J, Prendergast PJ. The effect of cytoskeletal disruption on pulsatile fluid flow-induced nitric oxide and prostaglandin e2 release in osteocytes and osteoblasts. Biochem Biophys Res Commun. April 29, 2005;330(1):341-348.
1988	Parfitt AM. Bone histomorphometry: proposed system for standardization of nomenclature, symbols, and units. Calcif Tiss Int. May 1988;42(5):284-286.
2004	Oliver WC, Pharr GM. Measurement of hardness and elastic modulus by instrumented indentation: advances in understanding and refinements to methodology. J Mater Res. January 2004;19(1):3-20.
1991	Cowin SC, Moss-Salentijn L, Moss ML. Candidates for the mechanosensory system in bone. J Biomech Eng. May 1991;113(2):191-197.
2006	Mann V, Huber C, Kogianni G, Jones D, Noble B. The influence of mechanical stimulation on osteocyte apoptosis and bone viability in human trabecular bone. J Musculoskel Neuron Interact. December 2006;6(4):408-417.
2006	Ün K, Bevill G, Keaveny TM. The effects of side-artifacts on the elastic modulus of trabecular bone. J Biomech. 2006;39(11):1955-1963.
1999	Wang L, Fritton SP, Cowin SC, Weinbaum S. Fluid pressure relaxation depends upon osteonal microstructure: modeling an oscillatory bending experiment. J Biomech. July 1999;32(7):663-672.
1977	Carter DR, Hayes WC. The compressive behavior of bone as a two-phase porous structure. J Bone Joint Surg. 1977;59A(7):954-962.
1994	Keller TS. Predicting the compressive mechanical behavior of bone. J Biomech. September 1994;27(9):1159-1168.
2000	Hutmacher DW. Scaffolds in tissue engineering bone and cartilage. Biomaterials. December 15, 2000;21(24):2529-2543.
2003	Morgan EF, Bayraktar HH, Keaveny TM. Trabecular bone modulus–density relationships depend on anatomic site. J Biomech. July 2003;36(7):897-904.
2008	Bonewald LF, Johnson ML. Osteocytes, mechanosensing and Wnt signaling. Bone. April 2008;42(4):606-615.
2004	Han Y, Cowin SC, Schaffler MB, Weinbaum S. Mechanotransduction and strain amplification in osteocyte cell processes. Proc Natl Acad Sci USA. November 23, 2004;101(47):16689-16694.
2000	Hoffler CE, Moore KE, Kozloff K, Zysset PK, Brown MB, Goldstein SA. Heterogeneity of bone lamellar-level elastic moduli. Bone. June 2000;26(6):603-609.
2003	Jones DB, Broeckmann E, Pohl T, Smith EL. Development of a mechanical testing and loading system for trabecular bone studies for long term culture. Eur Cell Mater. January–June 2003;5:48-60.
1989	Younger EM, Chapman MW. Morbidity at bone graft donor sites. J Orthop Trauma. September 1989;3(3):192-195.
1997	Gibson LJ, Ashby MF. Cellular Solids: Structure and Properties. 2nd ed. Cambridge, UK: Cambridge University Press; 1997. Cambridge Solid State Science Series.
1995	Duncan RL, Turner CH. Mechanotransduction and the functional response of bone to mechanical strain. Calcif Tiss Int. December 1995;57(5):344-358.
1987	Goldstein SA. The mechanical properties of trabecular bone: dependence on anatomic location and function. J Biomech. 1987;20(11-12):1055-1061.
2004	Salgado AJ, Coutinho OP, Reis RL. Bone tissue engineering: state of the art and future trends. Macromol Biosci. August 9, 2004;4(8):743-765.
1997	Owan I, Burr DB, Turner CH, Qiu J, Tu Y, Onyia JE, Duncan RL. Mechanotransduction in bone: osteoblasts are more responsive to fluid forces than mechanical strain. Am J Physiol Cell Physiol. September 1997;273(3):C810-C815.
1992	Oliver WC, Pharr GM. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J Mater Res. 1992;7(6):1564-1583.
2010	Lievers WB, Petryshyn AC, Poljsak AS, Waldman SD, Pilkey AK. Specimen diameter and “side artifacts” in cancellous bone evaluated using end-constrained elastic tension. Bone. August 2010;47(2):371-377.
2010	Lievers WB, Waldman SD, Pilkey AK. Minimizing specimen length in elastic testing of end-constrained cancellous bone. J Mech Behav Biomed Mater. January 2010;3(1):22-30.
2001	Adachi T, Tsubota K-i, Tomita Y, Hollister SJ. Trabecular surface remodeling simulation for cancellous bone using microstructural voxel finite element models. J Biomech Eng. October 2001;123(5):403-409.
1988	Recker RR, Kimmel DB, Parfitt MA, Davies MK, Keshawarz N, Hinders S. Static and tetracycline‐based bone histomorphometric data from 34 normal postmenopausal females. J Bone Miner Res. April 1988;3(2):133-344.
2001	Sikavitsas VI, Temenoff JS, Mikos AG. Biomaterials and bone mechanotransduction. Biomaterials. October 2001;22(19):2581-2593.
1988	Harrigan TP, Jasty M, Mann RW, Harris WH. Limitations of the continuum assumption in cancellous bone. J Biomech. 1988;21(4):269-275.
2005	Ruimerman R, Hilbers P, van Rietbergen B, Huiskes R. A theoretical framework for strain-related trabecular bone maintenance and adaptation. J Biomech. April 2005;38(4):931-941.
2010	Harrison NM, McHugh PE. Comparison of trabecular bone behavior in core and whole bone samples using high-resolution modeling of a vertebral body. Biomech Model Mechanobiol. 2010;9(4):469-480.
1965	Sneddon IN. The relation between load and penetration in the axisymmetric Boussinesq problem for a punch of arbitrary profile. Int J Eng Sci. May 1965;3(1):47-57.
1990	El Haj AJ, Minter SL, Rawlinson SCF, Suswillo R, Lanyon LE. Cellular responses to mechanical loading in vitro. J Bone Miner Res. September 1990;5(9):923-932.
2002	Burr DB, Robling AG, Turner CH. Effects of biomechanical stress on bones in animals. Bone. May 2002;30(5):781-786.
2001	Yang S, Leong K-F, Du Z, Chua C-K. The design of scaffolds for use in tissue engineering, I: traditional factors. Tissue Eng. December 2001;7(6):679-689.
1993	Langer R, Vacanti JP. Tissue engineering. Science. May 14, 1993;260(5110):920-926.
2007	Bevill G, Easley SK, Keaveny TM. Side-artifact errors in yield strength and elastic modulus for human trabecular bone and their dependence on bone volume fraction and anatomic site. J Biomech. 2007;40(15):3381-3388.
2006	Davies CM, Jones DB, Stoddart MJ, Koller K, Smith E, Archer CW, Richards RG. Mechanically loaded ex vivo bone culture system “Zetos”: systems and culture preparation. Eur Cell Mater. January–June 2006;11:57-75.
1995	Klein-Nulend J, van der Plas A, Semeins CM, Ajubi NE, Frangos JA, Nijweide PJ, Burger EH. Sensitivity of osteocytes to biomechanical stress in vitro. FASEB J. March 1995;9(5):441-445.
1994	Weinbaum S, Cowin SC, Zeng Y. A model for the excitation of osteocytes by mechanical loading-induced bone fluid shear stresses. J Biomech. March 1994;27(3):339-360.
1997	Klein‐Nulend J, Burger EH, Semeins CM, Raisz LG, Pilbeam CC. Pulsating fluid flow stimulates prostaglandin release and inducible prostaglandin g/h synthase mrna expression in primary mouse bone cells. J Bone Miner Res. January 1997;12(1):45-51.
2003	Lin ASP, Barrows TH, Cartmell SH, Guldberg RE. Microarchitectural and mechanical characterization of oriented porous polymer scaffolds. Biomaterials. February 2003;24(3):481-489.
2006	Seeman E, Delmas PD. Bone quality: the material and structural basis of bone strength and fragility. NEJM. May 25, 2006;354(21):2250-2261.
2010	Kamel MA, Picconi JL, Lara-Castillo N, Johnson ML. Activation of β-catenin signaling in MLO-Y4 osteocytic cells versus 2T3 osteoblastic cells by fluid flow shear stress and PGE2: implications for the study of mechanosensation in bone. Bone. November 2010;47(5):872-881.
2005	Hollister SJ. Porous scaffold design for tissue engineering. Nat Mater. July 2005;4(7):518-524.
2005	Karageorgiou V, Kaplan D. Porosity of 3D biomaterial scaffolds and osteogenesis. Biomaterials. September 2005;26(27):5474-5491.
1995	Klein-Nulend J, Semeins CM, Ajubi NE, Nijweide P, Burger EH. Pulsating fluid flow increases nitric oxide (NO) synthesis by osteocytes but not periosteal fibroblasts - correlation with prostaglandin upregulation. Biochem Biophys Res Commun. December 14, 1995;217(2):640-648.
1999	Burger EH, Klein-Nulend J. Mechanotransduction in bone: role of the lacunocanalicular network. FASEB J. May 1999;12(9001):S101-S112.
1996	Ajubi NE, Klein-Nulend J, Nijweide PJ, Vrijheid-Lammers T, Alblas MJ, Burger EH. Pulsating fluid flow increases prostaglandin production by cultured chicken osteocytes: a cytoskeleton-dependent process. Biochem Biophys Res Commun. August 5, 1996;225(1):62-68.
2006	Rezwan K, Chen QZ, Blaker JJ, Boccaccini AR. Biodegradable and bioactive porous polymer/inorganic composite scaffolds for bone tissue engineering. Biomaterials. June 2006;27(18):3413-3431.
2007	Cowin SC, Doty SB. Tissue Mechanics. Boca Raton, FL: Springer; 2007.
1992	Pharr GM, Oliver WC. Measurement of thin film mechanical properties using nanoindentation. MRS Bull. July 1992;17(7):28-33.

Year

Entry

1993

Lanyon LE. Osteocytes, strain detection, bone modeling and remodeling. Calcif Tiss Int. February 1993;53(suppl 1):S102-S107.

2008

Lewis G, Nyman JS. The use of nanoindentation for characterizing the properties of mineralized hard tissues: state-of-the art review. J Biomed Mater Res. October 2008;B87(1):286-301.

2000

Brown TD. Techniques for mechanical stimulation of cells in vitro: a review. J Biomech. January 2000;33(1):3-14.

1999

Rho J-Y, Pharr GM. Effects of drying on the mechanical properties of bovine femur measured by nanoindentation. J Mater Sci Mater Med. 1999;10(8):485-488.

1987

Frost HM. The mechanostat: a proposed pathogenic mechanism of osteoporoses and the bone mass effects of mechanical and nonmechanical agents. Bone Miner. April 1987;2(2):73-85.