Preparation and Properties of Poly(lactide-co-glycolide) (PLGA)/ Nano-Hydroxyapatite (NHA) Scaffolds by Thermally Induced Phase Separation and Rabbit MSCs Culture on Scaffolds

Abstract

Biodegradable polymer/bioceramic composites scaffold can overcome the limitation of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. To better mimic the mineral component and the microstructure of natural bone, novel nano-hydroxyapatite (NHA)/polymer composite scaffolds with high porosity and well-controlled pore architectures as well as high exposure of the bioactive ceramics to the scaffold surface is developed for efficient bone tissue engineering. In this article, regular and highly interconnected porous poly(lactide-co-glycolide) (PLGA)/NHA scaffolds are fabricated by thermally induced phase separation technique. The effects of solvent composition, polymer concentration, coarsening temperature, and coarsening time as well as NHA content on the micro-morphology, mechanical properties of the PLGA/NHA scaffolds are investigated. The results show that pore size of the PLGA/NHA scaffolds decrease with the increase of PLGA concentration and NHA content. The introduction of NHA greatly increase the mechanical properties and water absorption ability which greatly increase with the increase of NHA content. Mesenchymal stem cells are seeded and cultured in three-dimensional (3D) PLGA/NHA scaffolds to fabricate in vitro tissue engineering bone, which is investigated by adhesion rate, cell morphology, cell numbers, and alkaline phosphatase assay. The results display that the PLGA/NHA scaffolds exhibit significantly higher cell growth, alkaline phosphatase activity than PLGA scaffolds, especially the PLGA/NHA scaffolds with 10 wt.% NHA. The results suggest that the newly developed PLGA/NHA composite scaffolds may serve as an excellent 3D substrate for cell attachment and migration in bone tissue engineering.

Keywords

poly(lactide-co-glycolide)nano-hydroxyapatite thermally induced phase separation scaffold mesenchymal stem cells.

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References

Coombes, A.G. and Meikle, M.C. (2004). Resorbable Synthetic Polymers as Replacements for Bone Graft, Clin. Mater., 17: 35—67.

Kim, S.S. , Park, M.S. , Jeon , O. , Choi, C.Y. and Kim , B.S. (2006). Poly(lactide-co-glycolide)/Hydroxyapatite Composite Scaffolds for Bone Tissue Engineering, Biomaterials , 27: 1399—1409.

Laurencin, C.T. , Attawia, M. and Borden, M.D. (1999). Advancements in Tissue Engineered Bone Substitutes, Curr. Opin. Orthop., 10: 445—451.

Bagambisa, F.B. , Joos, U. and Schilli, W. (1993). Mechanisms and Structure of the Bond between Bone and Hydroxyapatite Ceramics , J. Biomed. Mater. Res., 27(8): 1047—1055.

Rizzi, S.C. , Heath, D.J. , Coombes, A.G. , Bock, N. , Textor, M. and Downes, S. (2001). Biodegradable Polymer/Hydroxyapatite Composites: Surface Analysis and Initial Attachment of Human Osteoblasts, J. Biomed. Mater. Res., 55: 475—486.

Wang, M. (2003). Developing Bioactive Composite Materials for Tissue Replacement, Biomaterials, 24: 2133—2151.

Van, L.P. , Li, F. , Keustermans , J.P. , Streydio, J.M. , Delannay, F. and Munting, E. (1995). The Influence of High Sintering Temperatures on the Mechanical Properties of Hydroxyapatite, J. Mater. Sci. Mater. Med., 6: 8—13.

Du, C. , Cui, F.Z. , Zhu, X.D. and de Groot, K. (1999). Three-dimensional Nano-HAp/Collagen Matrix Loading with Osteogenic Cells in Organ Culture, J. Biomed. Mater. Res., 44: 407—415.

Du, C. , Cui, F.Z. , Feng, Q.L. , Zhu, X.D. and de Groot, K. (1998). Tissue Response to Nano-Hydroxyapatite/Collagen Composite Implants in Marrow Cavity, J. Biomed. Mater. Res ., 42: 540—548.

10.

Webster, T.J. , Ergun, C. , Doremus , R.H. , Siegel, R.W. and Bizios, R. (2000). Specific Proteins Mediate Enhanced Osteoblast Adhesion on Nanophase Ceramics , J. Biomed. Mater. Res., 51: 475—483.

11.

Webster, T.J. , Siegel, R.W. and Bizios, R. (1999). Osteoblast Adhesion on Nanophase Ceramics, Biomaterials, 20: 1221—1227.

12.

Kulkarni, R.K. , Pani, K.C. and Neuman, C. (1966). Poly(lactic acid) for Surgical Implants, Arch. Surg., 93(6): 839—843.

13.

Cutright, D.E. and Hunsuck, E.E. (1971). Tissue Reaction to the Biodegradable Poly Lactic Acid Suture, Oral Surgery, Oral Medicine , Oral Pathology, 31(2): 134—139.

14.

Hollinger, J.O. and Battistone, G.C. (1986). Biodegradable Bone Repair Materials: Synthetic Polymers and Ceramics, Clinical Orthopaedics and Related Research, 207: 290—305.

15.

Bostman, O.M. (1991). Absorbable Implants for the Fixation of Fractures, J. Bone Joint Surg.-Am., 73A(1): 148—153.

16.

Cordewener, F.W. , Bos, R.R. and Rozema, F.R. (1996). Poly(L-lactide) Implants for Repair of Human Orbital Floor Defects: Clinical and Magnetic Resonance Imaging Evaluation of Long-Term Results, J. Oral Maxillofac. Surg., 54(1): 9—13.

17.

Bos, R.R.M. , Rozema, F.B. , Boering , G. , Nijenhius, A.J. , Pennings, A.J. , Verwey, A.B. , Nieuwenhuis, P. and Jansen, H.W.B. (1991). Degradation of and Tissue Reaction to Biodegradable Poly(l-lactide) for Use as Internal Fixation of Fractures: A Study in Rats, Biomaterials , 12(1): 32—36.

18.

Tormala, P. , Vaiionpaa, S. , Kilpikari , J. and Rokkanen P. (1987). The Effects of Fiber Reinforcement and Gold Plating on the Flexual and Tensile Strength of PGA/PLA Copolymer Materials In Vitro, Biomaterials , 8(1): 42—45.

19.

Zhang, R. and Ma, P.X. (1999). Porous Poly(L-lactic acid)/Apatite Composites Created by Biomimetic Process, J. Biomed. Mater. Res., 45: 285—293.

20.

Zhang, R. and Ma, P.X. (1999). Poly(alpha-hydroxyl acids)/Hydroxyapatite Porous Composites for Bone Tissue Engineering. I. Preparation and Morphology, J. Biomed. Mater. Res., 44: 446—455.

21.

Thomson, R.C. , Yaszemski, M.J. , Powers , J.M. and Mikos, A.G. (1998). Hydroxyapatite Fiber Reinforced Poly(alpha-hydroxy ester) Foams for Bone Regeneration , Biomaterials, 19: 1935—1943.

22.

Ishaug, S.L. , Crane, G.M. , Miller , M.J. , Yasko, A.W. , Yaszemski, M.J. and Mikos, A.G. (1997). Bone Formation by Three-Dimensional Stromal Osteoblast Culture in Biodegradable Polymer Scaffolds, J. Biomed. Mater. Res., 36: 17—28.

23.

Ma, P.X. , Zhang, R. , Xiao , G. and Franceschi, R. (2001). Engineering New Bone Tissue In Vitro on Highly Porous Poly(Alpha-Hydroxyl Acids)/Hydroxyapatite Composite Scaffolds, J. Biomed. Mater. Res., 54: 284—293.

24.

Mikos, A.G. , Lyman, M.D. , Freed L.E. and Langer, R. (1994). Wetting of Poly(L-Lactic Acid) and Poly(D,L-Lactic-Co-Glycolic Acid) Foams for Tissue Culture, Biomaterials, 15: 55—58.

25.

Mikos, A.G. , Sarakinos, G. , Vacanti, J.P. , Langer, R.S. and Cima, L.G. (1996). Biocompatible Polymer Membranes and Methods of Preparation of Three Dimensional Membrane Structures, US Patent No. 5514378.

26.

De Groot, J.H. , Kuijper, H.W. and Pennings, A.J. (1997). A Novel Method for Fabrication of Biodegradable Scaffolds with High Compression Moduli, J. Mater Sci.: Mater. Med., 8: 707—712.

27.

Mooney, D.J. , Baldwin, D.F. , Suh, N.P. , Vacanti, J.P. and Langer, R. (1996). Novel Approach to Fabricate Porous Sponges of Poly(D,L-Lactic-Co-Glycolic acid) without the Use of Organic Solvents, Biomaterials, 17(14): 1417—1422.

28.

Wang, K. , Tomas, C.H. and Healy, K.E. (1995). A Novel Method to Fabricate Bioabsorbable Scaffolds , Polymer, 36: 837—842.

29.

Nam, Y.S. and Park, T.G. (1999). Biodegradable Polymeric Microcellular Foams by Modified Thermally Induced Phase Separation Method , Biomaterials, 20: 1783—1790.

30.

Ma Peter, X. and Zhang, R.Y. (1999). Synthetic Nano-Scale Fibrous Extra Cellular Matrix, J. Biomedi. Mater. Res., 46: 60—72.

31.

Solchaga, L.A. , Johnstone, B. , Yoo , J.U. , Goldberg, V.M. and Caplan, A.I. (1999). High Variability in Rabbit Bone Marrow-Derived Mesenchymal Cell Preparations , Cell Transplant, 8: 511—519.

32.

Hua, F.J. , Park, T.G. and Lee , D.S. (2003). A Facile Preparation of Highly Interconnected Macroporous Poly(D,L-Lactic Acid-Co-Glycolic Acid) (PLGA) Scaffold by Liquid-Liquid Phase Separation of a PLGA-Dioxane-Water Ternary System, Polymer, 44: 1911—1920.

33.

Zhang, R.Y. and Ma, P.X. (1999). Poly(α-Hydroxyl Acids)/Hydroxyapatite Porous Composites for Bone-Tissue Engineering. I. Preparation and Morphology, J. Biomedi. Mater. Res., 44: 446—455.

34.

Zhang, R.Y. and Ma, P.X. (2001). Processing of Polymer Scaffolds: Phase Separation , In: Atala, A. and Lanza, R. (eds), Methods of Tissue Engineering , pp. 715—724, Academic Press, San Diego, CA.

35.

Nam, Y.S. and Park, T.G. (1999). Porous Biodegradable Polymeric Scaffolds Prepared by Thermally Induced Phase Separation, J. Biomed. Mater. Res., 47: 8—17.

36.

Binder, K. and Stauffer, D. (1974). Theory for the Slowing Down of the Relaxation and Spino dal Decomposition of Binary Mixtures, Physical Review Letters, 33: 1006—1009.

37.

Ambrosio, A.M. , Sahota, J.S. , Khan , Y. and Laurencin, C.T. (2001). A Novel Amorphous Calcium Phosphate Polymer Ceramic for Bone Repair: I. Synthesis and Characterization , J. Biomed. Mater. Res., 58: 295—301.

38.

Marra, K.G. , Szem, J.W. , Kumta , P.N. , DiMilla, P.A. and Weiss, L.E. (1999). In Vitro Analysis of Biodegradable Polymer Blend/Hydroxyapatite Composites for Bone Tissue Engineering , J. Biomed. Mater. Res., 47: 324—335.