title: Beneficial effect of hydrophilized porous polymer scaffolds in tissue-engineered cartilage formation.
abstract: Three dimensional (3D) porous poly(L-lactic acid) (PLLA) scaffolds were fabricated using a modified gas foaming method whose effervescent porogens were a mixture of sodium bicarbonate and citric acid. To improve chondrocyte adhesion, the scaffolds were then hydrophilized through oxygen plasma treatment and in situ graft polymerization of acrylic acid (AA). When the physical properties of AA-grafted scaffolds were examined, the porosity and pore size were 87 approximately 93% and 100 approximately 300 microm, respectively. The pore sizes were highly dependent on the varying ratios (w/w) between porogen and polymer solution. Influenced by their pore sizes, the compressive moduli of scaffolds significantly decreased with increasing pore size. The altered surface characteristics were clearly reflected in the reduced water contact angles that meant a significant hydrophilization with the modified polymer surface. Electron spectroscopy for chemical analysis (ESCA) and time-of-flight secondary ion mass spectrometer (ToF-SIMS) also confirmed the altered surface chemistry. When chondrocytes were seeded onto the AA-grafted PLLA scaffolds, cell adhesion and proliferation were substantially improved as compared to the unmodified scaffolds. The benefit of the modified scaffolds was clear in the gene expressions of collagen type II that was significantly upregulated after 4-week culture. Safranin-O staining also identified greater glycosaminoglycan (GAG) deposition in the modified scaffold. The AA-grafted porous polymer scaffolds were effective for cell adhesion and differentiation, making them a suitable platform for tissue-engineered cartilage.
authors.affiliation: Biomaterials Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, Korea.
authors.forename: Young Min
authors.initials: YM
authors.lastname: Ju
authors.forename: Kwideok
authors.initials: K
authors.lastname: Park
authors.forename: Jun Sik
authors.initials: JS
authors.lastname: Son
authors.forename: Jae-Jin
authors.initials: JJ
authors.lastname: Kim
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Rhie
authors.forename: Dong Keun
authors.initials: DK
authors.lastname: Han
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002356:Cartilage / Q000166:cytology / Q000502:physiology; D002448:Cell Adhesion; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D020219:Chondrogenesis / Q000502:physiology*; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D048091:Guided Tissue Regeneration / Q000295:instrumentation / Q000379:methods; D008422:Materials Testing; D011091:Polyesters / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011817:Rabbits; D013499:Surface Properties; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods; D054457:Tissue Scaffolds
chemical_list: D000179:Acrylates; D001672:Biocompatible Materials; D024042:Collagen Type I; D024043:Collagen Type II; D011091:Polyesters; D011108:Polymers; C033616:poly(lactide); C036658:acrylic acid