Processing and characterization of poly(lactic acid) based bioactive composites for biomedical scaffold application

The current study focuses on three-components material systems (poly(lactic acid) (PLA), poly("-caprolactone) (PCL) and wollastonite (W)) in view of possible application a biomedical scaffold constructs. Melt extruded PLA/PCL/W composites (PLCL15, PLCLW1, PLCLW4, PLCLW8 containing 0, 1, 4, 8 phr filler respectively) are batch foamed using compressed CO2 and the porous foams are studied for in vitro biocompatibility by seeding osteoblast cells. SEM images of the unfoamed polymers show immiscibility in all compositions. Materials have been tested under compressive load using dry and wet conditions (using phosphate buffered saline at pH 7.4) for in vitro study. Contact angle measurement shows enhanced hydrophilicity in the composites changing from 80° in PLCL15 to 72° in PLCLW8. The foams are found to be microcellular (5-8 µm) in morphology showing quite uniform pore distribution in the composites. The prepared foams, when studied as scaffold constructs, show osteoblast cell attachment and proliferation over the incubation period of 7 days. As expected, PLCLW8 containing highest amount of CaSiO3 supported maximum cell growth on its surface as visible from MTT assay data and SEM scans.

[1]  Chad Johnson,et al.  The effect of scaffold degradation rate on three-dimensional cell growth and angiogenesis. , 2004, Biomaterials.

[2]  Q. Fu,et al.  Kinetics-controlled compatibilization of immiscible polypropylene/polystyrene blends using nano-SiO2 particles , 2004 .

[3]  M. Shaw,et al.  Biodegradable HA-PLA 3-D porous scaffolds: effect of nano-sized filler content on scaffold properties. , 2005, Acta biomaterialia.

[4]  S. Ray,et al.  Well-controlled biodegradable nanocomposite foams: From microcellular to nanocellular , 2003 .

[5]  Yinghong Zhou,et al.  CaSiO₃ microstructure modulating the in vitro and in vivo bioactivity of poly(lactide-co-glycolide) microspheres. , 2011, Journal of biomedical materials research. Part A.

[6]  N. Washburn,et al.  Structure and mechanical properties of poly(?,?-lactic acid)/poly(ɛ-caprolactone) blends , 2003 .

[7]  Song Zhao,et al.  Preparation and characterization of a novel hydroxyapatite-wollastonite/silk fibroin composite , 2012 .

[8]  Tadashi Kokubo,et al.  Apatite formation on surfaces of ceramics, metals and polymers in body environment , 1998 .

[9]  W. Orts,et al.  Binary and ternary blends of polylactide, polycaprolactone and thermoplastic starch , 2008 .

[10]  L. Matuana,et al.  Cell morphology of extrusion foamed poly(lactic acid) using endothermic chemical foaming agent. , 2009, Bioresource technology.

[11]  K. Arakawa,et al.  Fracture micromechanisms of bioabsorbable PLLA/PCL polymer blends , 2007 .

[12]  L. Matuana,et al.  Effect of gas saturation conditions on the expansion ratio of microcellular poly(lactic acid)/wood-flour composites , 2010 .

[13]  P. Pagès,et al.  Processing of poly(lactic acid): characterization of chemical structure, thermal stability and mechanical properties , 2010 .

[14]  Ming Li,et al.  Preparation and in vitro bioactivities of calcium silicate nanophase materials , 2005 .

[15]  Jiang Chang,et al.  Preparation and characterization of bioactive and biodegradable Wollastonite/poly(D,L-lactic acid) composite scaffolds , 2004, Journal of materials science. Materials in medicine.

[16]  L. Janssen,et al.  The FT-IR studies of the interactions of CO2 and polymers having different chain groups , 2006 .

[17]  Yufang Zhu,et al.  A template route to the preparation of mesoporous amorphous calcium silicate with high in vitro bone-forming bioactivity. , 2007, Journal of biomedical materials research. Part B, Applied biomaterials.

[18]  Liang Xu,et al.  Preparation and in vitro degradation of novel bioactive polylactide/wollastonite scaffolds , 2009 .

[19]  C. Chen,et al.  Preparation and characterization of biodegradable PLA polymeric blends. , 2003, Biomaterials.

[20]  Christian G'Sell,et al.  Deformation and damage upon stretching of degradable polymers (PLA and PCL) , 2005 .

[21]  Shau‐Tarng Lee,et al.  Polymeric Foams : Mechanisms and Materials , 2004 .

[22]  J. Sarasua,et al.  Crystallization, morphology, and mechanical behavior of polylactide/poly(ε‐caprolactone) blends , 2006 .

[23]  J F Orr,et al.  Processing, annealing and sterilisation of poly-L-lactide. , 2004, Biomaterials.

[24]  Y. Nho,et al.  Preparation of porous poly(ɛ-caprolactone) scaffolds by gas foaming process and in vitro/in vivo degradation behavior using γ-ray irradiation , 2008 .

[25]  Chin-San Wu,et al.  Preparation and characterization of ternary blends composed of polylactide, poly(ɛ-caprolactone) and starch , 2009 .

[26]  M. L. Lorenzo.  Crystallization behavior of poly(l-lactic acid) , 2005 .

[27]  V. Divjaković,et al.  Effect of Nano-and Micro-Silica Fillers on Polyurethane Foam Properties , 2002 .

[28]  A. Janorkar,et al.  Poly(lactic acid) modifications , 2010 .

[29]  S. Ramakrishna,et al.  Biomedical applications of polymer-composite materials: a review , 2001 .

[30]  W. Murphy,et al.  Effects of pseudowollastonite (CaSiO3) bioceramic on in vitro activity of human mesenchymal stem cells. , 2010, Biomaterials.

[31]  Changsheng Liu,et al.  Preparation and characterization of bioactive mesoporous wollastonite - Polycaprolactone composite scaffold. , 2009, Biomaterials.

[32]  Jiang Chang,et al.  Fabrication and characterization of bioactive wollastonite/PHBV composite scaffolds. , 2004, Biomaterials.

[33]  Martial Sauceau,et al.  New challenges in polymer foaming: A review of extrusion processes assisted by supercritical carbon dioxide , 2011 .

[34]  Min Wang,et al.  Developing bioactive composite materials for tissue replacement. , 2003, Biomaterials.

[35]  Frank V. Bright,et al.  Specific Intermolecular Interaction of Carbon Dioxide with Polymers , 1996 .

[36]  Ling Chen,et al.  Cold crystallization and postmelting crystallization of PLA plasticized by compressed carbon dioxide , 2008 .