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Biomedical subjects

Gamze Torun Köse

Publications and source records attributed to Gamze Torun Köse.

5 recordsLinked to original sources
PubMed2005

Tissue engineering of bone on micropatterned biodegradable polyester films.

In this study, the effect of cell alignment on proliferation and phenotype expression of rat bone marrow derived osteoblasts on micropatterned (MP) PHBV and P(L/D,L)LA films with 27 microm wide parallel microgrooves was investigated. Immobilization of fibrinogen (Fb) on film surface by adsorption increased hydrophilicity, while covalent immobilization decreased it. Amount of Fb immobilized was significantly higher upon covalent bonding (153.1+/-42.4 microg Fb/cm2) than when adsorbed (10.0+/-3.3 microg Fb/cm2). It was observed that the presence of MP did not influence cell proliferation in the long run. Osteoblasts on MP films with adsorbed (MP Fb(a)) and covalently immobilized Fb (MP Fb(i)) aligned parallel to the groove axis with mean deviation angles of 10.59+/-23.47 and 29.02+/-33.03 degrees, respectively, while on tissue culture polystyrene (TCP), on unpatterned films (UNP) and on UNP with adsorbed Fb (UNP Fb(a)) alignment with an arbitrary axis was much higher: 46.66+/-24.98, 48.72+/-31.19, 47.74+/-27.29 degrees, respectively. Fb-free MP films were not effective in cell alignment, and clumps were formed. Cell alignment achieved on MP Fb(a) films did not influence cell proliferation, but increased differentiation, as shown by ALP activity per cell and the evenness and the amount of calcium phosphate deposition. It was concluded that orientation of cells was influential on their differentiation and also, MP cell carriers with chemical cues on their surfaces are important in improving tissue repair.

Animals↗
PubMed2005

Tissue engineered cartilage on collagen and PHBV matrices.

Cartilage engineering is a very novel approach to tissue repair through use of implants. Matrices of collagen containing calcium phosphate (CaP-Gelfix), and matrices of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) were produced to create a cartilage via tissue engineering. The matrices were characterized by scanning electron microscopy (SEM) and electron diffraction spectroscopy (EDS). Porosity and void volume analysis were carried out to characterize the matrices. Chondrocytes were isolated from the proximal humerus of 22 week-old male, adult, local albino rabbits. For cell type characterization, Type II collagen was measured by Western Blot analysis. The foams were seeded with 1x10(6) chondrocytes and histological examinations were carried out to assess cell-matrix interaction. Macroscopic examination showed that PHBV (with or without chondrocytes) maintained its integrity for 21 days, while CaP-Gelfix was deformed and degraded within 15 days. Cell-containing and cell-free matrices were implanted into full thickness cartilage defects (4.5 mm in diameter and 4 mm in depth) at the patellar groove on the right and left knees of eight rabbits, respectively. In vivo results at 8 and 20 weeks with chondrocyte seeded PHBV matrices presented early cartilage formation resembling normal articular cartilage and revealed minimal foreign body reaction. In CaP-Gelfix matrices, fibrocartilage formation and bone invasion was noted in 20 weeks. Cells maintained their phenotype in both matrices. PHBV had better healing response than CaP-Gelfix. Both matrices were effective in cartilage regeneration. These matrices have great potential for use in the repair of joint cartilage defects.

Absorbable Implants↗
PubMed2003

Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) based tissue engineering matrices.

In this study, the aim was to produce tissue-engineered bone using osteoblasts and a novel matrix material, poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV). In order to prepare a porous PHBV matrix with uniform pore size, sucrose crystals were loaded in the foam and then leached leaving pores behind. The surface of the PHBV matrix was treated with rf-oxygen plasma to increase the surface hydrophilicity. SEM examination of the PHBV matrices was carried out. Stability of PHBV foams in aqueous media was studied. The pH decrease is an indication of the degradation extent. The weight and density were unchanged for a period of 120 days but then a significant decrease was observed for the rest of the study. Osteoblast cells were then isolated from rat bone marrow and seeded onto PHBV matrices. The metabolization and proliferation on the foams was determined with MTS assay which showed that osteoblasts proliferated on PHBV. It was also found that cells proliferated better on large pore size foams (300-500 microm) than on the small pore size foams (75-300 microm). Production of ALP was measured spectrophotometrically. The present study demonstrated that PHBV matrices are suitable substrates for osteoblast proliferation and differentiation.

Journal Article↗
PubMedDate not supplied

In vivo tissue engineering of bone using poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) and collagen scaffolds.

Porous poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) and calcium phosphate-loaded collagen (CaP-Gelfix) foams were seeded with rat bone marrow stromal cells and implanted into defects created in rat femurs to study in vivo bone formation and to test their suitability for use in bone tissue engineering. At 3 and 6 weeks, new bone formation was evaluated by macroscopy, radiography, dual-energy X-ray absorptiometry (DEXA), and quantitative computerized tomography (QCT). Atomic contents of the implants were further assessed by QCT. Some initial inflammation that significantly decreased with time was observed in the CaP-Gelfix group. PHBV inflammation was minimal at all stages. Fibrous tissue formation in the CaP-Gelfix group was more than in the PHBV group. Both cell-loaded and cell-free PHBV matrices elicited minimal fibrous tissue formation during the 6-week implantation duration. Macroscopic and radiological studies demonstrated better healing with PHBV matrices than with CaP-Gelfix in 3 weeks. Histologically, fibrous connective tissue establishment and inflammation scores were significantly higher in the CaP-Gelfix group when compared with the PHBV group at both time intervals. At 6 weeks, however, the extent of healing was almost the same with both implants. DEXA and QCT results indicated that there was an increase in bone mineral density in both PHBV and CaP-Gelfix implants at the end of 6 weeks. This study suggests that even though PHBV and CaP-Gelfix have different bulk and surface chemistries they both are promising cell carriers that may be suitable for use in bone tissue engineering.

Animals↗