ABSTRACT
Highly porous poly(ethylene glycol) (PEG) hydrogel scaffolds crosslinked with hydrolyzable polyrotaxane for cartilage tissue engineering were prepared by a solvent casting/salt leaching technique. The resultant scaffolds have well interconnected microporous structures ranging from 87 to 90%. Pore sizes ranging from 115.5-220.9 microm appeared to be dependent on the size of the sieved sodium chloride particulates. Moreover, a dense surface skin layer was not found on either side of the scaffold surfaces. Using microscopic Alcian blue staining of the chondrocyte-seeded scaffolds, well adhered cells and newly produced glycosaminoglycans (GAG) were confirmed. Following the initial chondrocyte seeding onto the hydrogel scaffolds, the cell number was significantly increased, reaching 149, 877, and 1228 cells/mg of tissue at 8, 15, and 21 days in culture, respectively. The micrograph shows well adhered and spread chondrocytes in the interior pores and a cartilaginous extracellular matrix with a GAG fraction produced from the chondrocytes. Results suggest that the PEG hydrogel scaffolds crosslinked with the hydrolyzable polyrotaxane are a promising candidate for chondrocyte culture.
Subject(s)
Biocompatible Materials/chemistry , Cartilage/metabolism , Cross-Linking Reagents/chemistry , Cyclodextrins/chemistry , Poloxamer/chemistry , Polyethylene Glycols/chemistry , Rotaxanes , Tissue Engineering , Absorbable Implants , Animals , Cartilage/cytology , Chondrocytes/cytology , Chondrocytes/metabolism , Cyclodextrins/metabolism , Hydrogels/chemistry , Hydrogels/metabolism , Materials Testing , Molecular Structure , Poloxamer/metabolism , Polyethylene Glycols/metabolism , Rabbits , Surface PropertiesABSTRACT
We have prepared porous polyrotaxane hydrogels by using the salt leaching technique. Porous hydrogels were found to have a uniform and highly porous structure. The size of pores in each hydrogel was directly proportional to the size of the sodium chloride particle used. Structural uniformity of the hydrogels is useful not only for uniform cell distribution, but also for well-controlled material properties. Uniform pore size and distribution may ensure the diffusion of nutrients throughout of the gel and the removal of metabolic wastes from the system. The results of an erosion study in phosphate-buffered saline showed that the erosion time of porous polyrotaxane hydrogels was controlled by the poly(ethylene glycol) (PEG) content in the hydrogels. The erosion time of the porous polyrotaxane hydrogel was observed to be almost the same with the non-porous polyrotaxane hydrogel with the same PEG content. From the erosion study, the erosion time of the polyrotaxane hydrogel may be independent of its morphology. Easy control of the erosion time in the polyrotaxane hydrogels is useful in the preparation of scaffolds for tissue engineering.
