Biodegradable Composite Scaffolds Research Articles

Biodegradable composite scaffolds with an interconnected spherical network for bone tissue engineering

Tissue engineering scaffolds are highly engineered structures that accommodate cells, facilitate their expression, and resorb to facilitate regeneration of tissue. A new technique for producing controlled pore shape and pore size interconnectivity offers promise for application as a tissue engineering scaffold. Salt particles were spheroidized in a flame and sintered to provide an interconnecting salt template. The salt template was filled with a carbonated fluorapatite powder and a polylactic polymer to produce a composite scaffold. It was found that a higher pore space is possible with the use of spherical and larger salt particle sizes. This technique can produce scaffolds with good interconnectivity and be suitable for producing pore size graded bodies.

Preparation and characterization of macroporous chitosan-gelatin/beta-tricalcium phosphate composite scaffolds for bone tissue engineering.

A biodegradable composite scaffold was developed using beta-tricalcium phosphate (beta-TCP) with chitosan (CS) and gelatin (Gel) in the form of a hybrid polymer network (HPN) via co-crosslinking with glutaraldehyde. Various types of scaffolds were prepared by freezing and lyophilizing. These scaffolds were characterized by Fourier transform infrared, X-ray diffractometer, and scanning electron microscopy. The macroporous composite scaffolds exhibited different pore structures. Compressive properties were improved, especially compressive modulus from 3.9-10.9 MPa. Biocompatibility was evaluated subcutaneously on rabbits. A mild inflammatory response was observed over 12 weeks. The results suggest that the scaffolds can be utilized in nonloading bone regeneration.

IN VIVO OSTEOGENETIC POTENTIAL BONE MARROW MESENCHYMAL STEM CELL ON β-TRICALCIUM PHOSPHATE (β-TCP) / COLLAGEN SPONGE

Purpose: When autologous bone grafts are used, we needed surgical invasion to donor sites and autografts are limited amounts. Then, tissue engineered bone using bone marrow mesenchymal stem cells (MSCs) may supersede the need of such procedures. It is desirable that scaffold is biodegradable and replaced by new bone. The aim of this study is to observe osteogenic potential of biodegradable composite scaffold consisting of β-TCP and collagen sponge using 3D cultured MSCs in vivo. Methods: The β-TCP was used as the granular porous ceramic. Granule size was 0.5 to 1.0mm. A 1% atelo-collagen (type I and III) hydrochloride solution and β-TCP granule were mixed and homogenized. The β-TCP/collagen solution was poured into a mold and freeze-dried, followed by dehydrothermal cross-linkage. The bone marrow cells were harvested from the head of humerus of a beagle dog. The cell cultures were grown for 4 weeks to obtain plastic-adherent cell population including MSCs. The scaffold was soaked in cell suspension for 24 hours. They were implanted under the dorsum skin of dog, and were examined after 4,12 weeks. Results: At 4 weeks, the histological specimens showed that collagen sponge was degraded partially, and the most of β-TCP granules remained. Osteoblasts were founded surrounding of granules, and introduced a few newly bone formation. At 12 weeks, osteoblasts were decreased, but a lot of maturely formed bone was observed. The most of β-TCP granules were degraded, and replaced by new bone. This scaffold has potential for bone tissue engineering.

Plasma-sprayed calcium phosphate particles with high bioactivity and their use in bioactive scaffolds

Highly crystalline feedstock hydroxyapatite (HA) particles with irregular shapes were spheroidized by plasma spraying them onto the surface of ice blocks or into water. The spherical Ca–P particles thus produced contained various amounts of the amorphous phase which were controlled by the stand-off distance between the spray nozzle and the surface of ice blocks or water. The smooth surface morphology without cracks of spherical Ca–P particles indicated that there were very low thermal stresses in these particles. Plasma-sprayed Ca–P particles were highly bioactive due to their amorphous component and hence quickly induced the formation of bone-like apatite on their surfaces after they were immersed in an acellular simulated body fluid at 36.5°C. Bone-like apatite nucleated on dissolved surface (due to the amorphous phase) of individual Ca–P particles and grew to coalesce between neighboring Ca–P particles thus forming an integrated apatite plate. Bioactive and biodegradable composite scaffolds were produced by incorporating plasma-sprayed Ca–P particles into a degradable polymer. In vitro experiments showed that plasma-sprayed Ca–P particles enhanced the formation of bone-like apatite on the pore surface of Ca–P/PLLA composite scaffolds.