Tissue engineering: Mechanical biological effects and functional reconstruction goals.

摘要

Tissue engineering offers a promising new approach to bone tissue grafting. One material that has received attention in this regard is the polymer poly (lactic-co-glycolic acid) (PLGA). It has the advantage of controllable bioresorption and ease of processing, Another material of interest is bioactive glass (BG), which shows the ability to stimulate osteoblastic differentiation of osteoprogenitor cells. In this study, PLGA-30%BG microspheres were formed into a porous scaffold for bone tissue engineering and examined for their ability to promote osteogenesis of marrow stromal cells (MSC). This microsphere based porous scaffold supported both MSC proliferation and promoted MSC differentiation into cells expressing the osteoblast phenotype. To further understand the mechanisms underlying the osteogenic effect of PLGA-BG composite scaffolds, we tested whether solution-mediated factors derived from composite scaffolds/hybrids can promote osteogenesis of marrow stromal cells. The dissolution product from BG components in the scaffold, in concert with the three-dimensional structure of scaffold, contributes to the solution-mediated effect on osteogenesis of MSC, Thus PLGA-BG composites demonstrate significant potential as a bone replacement material.; The use of tissue-engineering method holds great promise for treating degenerative disc disease. Because the success of tissue-engineered approach depends on maintenance or restoration of the mechanical function of the intervertebral disc, it is useful to study the initial mechanical performance of the disc after implantation of a hybrid material composed of a porous scaffold and seeded cells. A three-dimensional nonlinear finite element model of the L2--L3 disc-vertebra unit was constructed, validated, and used to study the mechanical behavior of a tissue engineered intervertebral disc. The results of this study suggest that a well-designed tissue engineered scaffold preferably has a modulus in the range of 5 to 10 MPa and a compressive strength exceeding 1.67 MPa. Implanted scaffolds with such properties can then achieve the goal of restoring the disc height and distributing stress under various loading conditions.