Composite Scaffolds For Bone Tissue Engineering Research Articles

Fabrication and Characterization of Polycaprolactone/Zein and Polycaprolactone/Zein/Bioglass Composite Scaffolds for BoneTissue Engineering

Fabrication and Characterization of Polycaprolactone/Zein and Polycaprolactone/Zein/Bioglass Composite Scaffolds for BoneTissue Engineering

PGA-incorporated collagen: Toward a biodegradable composite scaffold for bone-tissue engineering.

Nowadays composite scaffolds based on synthetic and natural biomaterials have got attention to increase healing of non-union bone fractures. To this end, different aspects of collagen sponge incorporated with poly(glycolic acid) (PGA) fiber were investigated in this study. Collagen solution (6.33 mg/mL) with PGA fibers (collagen/fiber ratio [w/w]: 4.22, 2.11, 1.06, 0.52) was freeze-dried, followed by dehydrothermal cross-linking to obtain collagen sponge incorporating PGA fibers. Properties of scaffold for cell viability, proliferation, and differentiation of mesenchymal stem cells (MSCs) were evaluated. Scanning electron microscopy showed that collagen sponge exhibited an interconnected pore structure with an average pore size of 190 μm, irrespective of PGA fiber incorporation. The collagen-PGA sponge was superior to the original collagen sponge in terms of the initial attachment, proliferation rate, and osteogenic differentiation of the bone marrow-MSCs (BM-MSC). The shrinkage of sponges during cell culture was significantly suppressed by fiber incorporation. Incorporation of PGA fiber is a simple and promising way to reinforce collagen sponge without impairing biocompatibility. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2020-2028, 2016.

Preparation and evaluation of biomimetric nano-hydroxyapatite-based composite scaffolds for bone-tissue engineering

In the present study, novel biomimetic composite scaffolds with a composition similar to that of natural bone were prepared, using nano-hydroxyapatite, collagen, and phosphatidylserine. The scaffolds possess an interconnected porous structure with a porosity of 84%. The pore size ranges from several micrometers up to about 400 μm. In-vitro studies in simulated body fluids showed that the morphologies of the products derived from mineralization can be regulated by the extracellular matrix components of the scaffolds; this in turn leads to creation of a large number of hydroxyapatite crystals on the scaffold surface. The regulatory properties of collagen and phosphatidylserine also influenced the cell response to the composite scaffolds. MC3T3-E1 cells attached and spread on the surfaces of the materials and interacted with the substrates; this may be the result of charged groups on the composite materials. Radiological analysis suggested that calluses and bone bridges formed in defects within 12 weeks. These composite scaffolds may therefore be a suitable replacement in bone-tissue engineering.

<i>In Vitro</i> Degradation and Protein Adsorption Characteristics of PHBV/PLLA Blends and PHBV/PLLA-Based Tissue Engineering Scaffolds

Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) was used to make composite scaffolds for bone tissue engineering in our previous studies. To control the degradation rate and process of composite scaffolds, PHBV was blended with poly(L-lactic acid) (PLLA), which has a much higher degradation rate than PHBV, and PHBV/PLLA blends were used as polymer matrices for composite scaffolds. Composite scaffolds based on these blends and containing nano-sized hydroxyapatite (nHA) were fabricated using an emulsion freezing / freeze-drying technique. Non-porous films of PHBV/PLLA blends were prepared using the solvent casting method. In vitro degradation tests of non-porous PHBV/PLLA blends and porous composite scaffolds were conducted by immersing samples in phosphate buffered saline (PBS) for various periods of time. It was found that the composition of polymer blends affected water uptake of films and scaffolds. For PHBV/PLLA-based scaffolds, the incorporated nHA particles also significantly increased water uptake within the initial immersion time. Both PHBV/PLLA blends and composite scaffolds underwent rapid weight losses within the first few weeks. The degradation of composite scaffolds arose from the dissolution of nHA particles and degradation of the PLLA component of polymer blends. Composite scaffolds exhibited enhanced adsorption of bovine serum albumin (BSA), a model protein, in the current study.

Poly(α‐hydroxyl acids)/hydroxyapatite porous composites for bone‐tissue engineering. I. Preparation and morphology

Tissue engineering has shown great promise for creating biological alternatives for implants. In this approach, scaffolding plays a pivotal role. Hydroxyapatite mimics the natural bone mineral and has shown good bone-bonding properties. This paper describes the preparation and morphologies of three-dimensional porous composites from poly(L-lactic acid) (PLLA) or poly(D,L-lactic acid-co-glycolic acid) (PLGA) solution and hydroxyapatite (HAP). A thermally induced phase separation technique was used to create the highly porous composite scaffolds for bone-tissue engineering. Freeze drying of the phase-separated polymer/HAP/solvent mixtures produced hard and tough foams with a co-continuous structure of interconnected pores and a polymer/HAP composite skeleton. The microstructure of the pores and the walls was controlled by varying the polymer concentration, HAP content, quenching temperature, polymer, and solvent utilized. The porosity increased with decreasing polymer concentration and HAP content. Foams with porosity as high as 95% were achieved. Pore sizes ranging from several microns to a few hundred microns were obtained. The composite foams showed a significant improvement in mechanical properties over pure polymer foams. They are promising scaffolds for bone-tissue engineering. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 44, 446–455, 1999.