Papers by Keyword: Chondrocyte

Abstract: Atomic Force Microscopy (AFM) based nanoindentation is a widely used technique for measuring mechanical properties of living cells, providing information for understanding their mechanobiological behavior. However, very local properties of cell surfaces have not been characterized earlier. The goal of this study was to develop an AFM-based technique to determine local elastic properties of bovine articular chondrocytes. The Youngs modulus of chondrocytes was 19.3 ± 5.6 kPa for spread cells and 10 ± 4.1 kPa for the round cells. The results were compared to previous studies in which different techniques were used to obtain more global properties of chondrocytes. Our findings suggest that using nanosized AFM tips, the very local cell properties can be measured.

Abstract: Mechano-active scaffolds were fabricated from very elastic poly(L-lactide-co-ε-carprolactone). The scaffolds with 80 % porosity and 300~500 μm pore size were prepared by a gel-pressing method. As a control group for elastic properties of polymer scaffolds, rigid poly L-lactide scaffolds were fabricated. The scaffolds were seeded with chondrocytes and cultured to evaluate the effect of elastic properties of polymer scaffolds for the differentiation and the ECM secretion of chondrocytes. Also, the chondrocytes-seeded constructs were implanted in nude mice subcutaneously to investigate their biocompatibility and cartilage formation. From the biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondral extracellular matrix was increased through mechanical stimulation of dynamic environment in the dynamic body systems. Histological analysis showed that implants of PLCL constructs formed mature and well-developed cartilaginous tissue, as evidenced by chondrocytes within lacunae. Consequently, the elastic PLCL scaffolds could be used to engineer cartilage in mechanically dynamic environments

Abstract: PLGA (75:25)/hydroxyapatite (HA) composite films were fabricated by solvent-casting method to investigate the effect of various hydroxyapatite content ratio to the PLGA film for cellular attachment and proliferation. Mechanical property of the composite film was characterized by tensile test. The ultimate tensile strength of 10% HA content film was two folds higher than control group. The surface of the film was characterized by contact angle measurement. The PLGA/HA composite film was more hydrophilic than control film. In vitro chondrocyte responses to the composite films were measured by cellular attachment and proliferation test. The attached and proliferated cells were significantly higher on PLGA/HA (10%) composite film than control group (1.44 times higher in attachment test and 1.31 times higher for 6th-day at culture in proliferation assaying, p<0.05). Base on these finding, the PLGA/HA (10%) composite was effective for the cell attachment for the initial stage of cultivation and cell proliferation.

Abstract: Nonporous PLLA film and porous PLLA scaffolds were prepared and then grafted with acrylic acid (AA) using in situ direct plasma treatment to obtain PLLA-g-PAA. Chondrocytes isolated from rabbit knee articular cartilages were cultivated in Dulbecco’s modified eagle medium- F12 (DMEM-F12) containing 10% fetal bovine serum (FBS) and 1% antibiotics and passaged twice before cell seeding. Once seeded on either PLLA films or scaffolds, they were placed in a bioreactor system and an intermittent hydrodynamic pressure (IHP) was applied in 3 bars, while turned on for 2 min and off for 28 min during 15-day culture. AA grafting to PLLA surface was confirmed from various surface analyses. From WST-1 assay, chondrocyte proliferation was significantly improved with dynamic IHP for PLLA and PLLA-g-PAA scaffolds as compared to static culture. This study indicates that IHP may have significant influence on chondrocytes behavior in 3D culture environment.

Abstract: This paper compares the characteristics of chondrocyte adhesion on two types of threedimensional (3-D) scaffold: types A and B. These 3-D scaffolds can be repeatedly constructed with the same dimensions using microstereolithography, a system that allows the fabrication of predesigned internal structures, such as pore size and porosity, by stacking the photopolymerized material. In tissue engineering, chondrocyte adhesion to a scaffold should have a major effect on the regeneration of cartilage. In this regard, we evaluated chondrocyte adhesion to two types of scaffold and found that chondrocyte adhesion was better on the type B scaffold than on the type A, demonstrating the importance of scaffold geometry in chondrocyte adhesion.

Abstract: Attachment and viability of different cell types(fibrioblast, chondrocyte and osteoblast ) was observed on two forms of silk (mat & Three-dimensional scaffolds). The osteoblasts behaviors cultured on silk mat were significantly higher than that found on 3-D silk fibroin scaffold (3-D SF scaffold). In the MTT assay, the cell viability of fibroblasts, chondrocyte and osteoblasts seeded on 2-D nanofiber mat was (2-D mat) significantly higher than that found on 3-D SF scaffold. Similar result could be seen from SEM observation and cell attachment study. However, alkaline phosphatase activity was significantly increased on 3-D SF scaffold than on2-D nanofiber

Abstract: A novel porous composite scaffold of nano-HA/poly (lactic-co-glycolic) (PLGA) was fabricated by solvent casting/particulate leaching method. Chondrocytes were isolated from the knee articular joints of a rabbit, and then seeded in the scaffolds. The cell-loaded scaffolds were cultured in vitro for 5 days before implantation. Full-thickness articular cartilage defects were created in rabbits, and filled with and without the cell-loaded nano-HA/PLGA scaffolds. The implants were harvested after in vivo incubation of 2 and 5 weeks. Cartilaginous tissues were observed at defects repaired with the cell-loaded scaffolds, while only fibrous tissues were found for the control groups. The repaired tissues were evaluated histologically by hematoxylin and eosin staining. Results revealed that nano-HA/PLGA composite scaffolds facilitated adheration of cells in vitro, and the nano-HA particles could prevented the scaffolds from collapsing and promoted the formation of cartilaginous tissue in vivo.

Abstract: A novel collagen sponge that can protect cell leakage during cell seeding was developed by wrapping all the surfaces except the upside of a collagen sponge with membrane that has pores smaller than cell. The collagen sponge was used for three-dimensional culture of human bone marrow-derived mesenchymal stem cells (MSCs). The cells adhered to the collagen, and proliferated to fill the spaces in the sponge. The cell seeding efficiency was higher than 95%. The MSCs cultured in the collagen sponge in the chondrogenic induction medium supplemented with TGF-β3 and BMP6 expressed genes encoding type II collagen, SOX9 and aggrecan. HE staining indicated the round morphology of differentiated cells and the extracelluler matrices were positively stained by safranin O and toluidine blue. Type II collagen and cartilage proteoglycan were detected by immunostaining with anti-type II collagen and anti-cartilage proteoglycan. These results suggest the chondrogenic differentiation of MSCs. The collagen sponge facilitated cell seeding and chondrogenic differentiation of MSCs, and will be useful for cartilage tissue engineering.

Abstract: In this study, we investigated the effect of the use of alginate sponge as a chondrocyte-3D scaffold for the construction of a cartilage graft. Alginate sponge was made by 5% alginic acid which was crosslinked by CaCl2. Chondrocytes were obtained from a nasal septum after the operation and cultured in 3D alginate sponge. For analysis of cell differentiation, we have checked aggrecan, collagen type I and II using RT-PCR and performed the histological and scanning electron microscopy analysis. Our experiments showed that alginate sponge of 5% promoted sufficient chondrocyte proliferation and differentiation, resulting in the formation of a specific cartilage matrix. The sponge presents new perspectives with respect to in vitro production of "artificial" cartilage. We conclude that the alginate sponges have potential as a scaffold for cartilage tissue engineering.

Abstract: Understanding chondrocyte behavior inside complex, three-dimensional environments with controlled patterning of geometrical factors would provide significant insights into the basic biology of tissue regenerations. One of the fundamental limitations in studying such behavior has been the inability to fabricate controlled 3D structures. To overcome this problem, we have developed a three-dimensional microfabrication system. This system allows fabrication of predesigned internal architectures and pore size by stacking up the photopolymerized materials. Photopolymer SL5180 was used as the 3D microfabricated scaffolds. The results demonstrate that controllable and reproducible inner-architecture can be fabricated. Chondrocytes from human nasal septum were cultured in 3D scaffolds for cell adhesion behavior. Such 3D scaffolds might provide effective key factors to study cell behavior in complex environments and could eventually lead to optimum design of scaffolds in various tissue regenerations such as cartilage, bone, etc. in a near future.