Polylactide scaffolds

Microcellular foams can be produced by thermally induced phase separation (TIPS) [47, 74, 76], The induced spinodal decomposition can be optimized to generate, e.g., polylactide scaffolds with the porous morphology and physicomechanical characteristics of a foam. Interesting materials can be constructed in a simple process. These materials exhibited bundles of channels with a diameter of 400 pm. The internal walls of the tubular macropores have a porous substructure with pore diameters of " 10 pm. It appears to be remarkable that the channels have a preferential... 

Maquet, V., Martin, D., Malgrange, B., Franzen, R., Schoenen, J., Moonen, G., Jerome, R. Peripheral nerve regeneration using bioresorbable macroporous polylactide scaffolds. J. Biomed. Mater. Res. 52, 639-651 (2000)... 

CH1 Chen, J.-S., Tu, S.-L., and Tsay, R.-Y., A morphological study of porous polylactide scaffolds prepared by thermally induced phase separation, J. Taiwan Inst. Chem. Eng., 4, 229, 2010. 

It is well known that proliferation or differentiation of nerve or muscle tissue can be enhanced by electrical stimulation, which is in part attributed to the propagation of action potentials upon stimulation. To exploit these physiological events, composites of biodegradable polymers with electroconduc-tive materials have been investigated for effective transmission of electrical signals to the cells cultured on them. PLCL and polyaniline, one of the widely used electrically conductive materials, were mixed to fabricate the nanofiber meshes, illustrating that myotube formation was accelerated when the myoblasts were cultured on polyaniline-containing nanofibers compared to that of PLCL-only nanofibers, even without electrical stimulation (Jun et ah, 2009). Another electroconductive polymer, polypyrrole, was also used as a composite with other synthetic polymers. For example, polypyrrole was incorporated as particles into polylactide scaffolds, and the fibroblasts cultured on them with various intensities of DC current showed controlled proliferation in a current-dependent manner (Shi et al., 2004). 

The above mentioned scaffolds were made completely of the ceramic materials. Other potential materials which could be used to fabricate a novel construct for the repair of ciitical-sized bone defects is a novel material made of biodegradable polymer reinforced with ceramics particles. The properties of such a composite depend on 1) properties of the polymer used for the matrix and properties of the ceramics used for the reinforcement, 2) composition of the composite (i.e. content of ceramic particles) and 3) size, shape and arrangement of the particles in the matrix. Several polymer-composite composites have been used for scaffolds fabrication including polylactide (PLA) and polycaprolacton (PCL) reinforced with calcium phosphate (CaP) micro and nanoparticles. Authors proposed a novel composite material by blending copolymer -Poly(L-lactide-co-D,E-lactide) (PLDLLA) a copolymer with a ceramic - Tri-Calcium Phosphate... 

Selection of a tissue engineering substrate includes a choice between absorbable and nonabsorbable material, as well as a choice between synthetic and naturally derived materials. The most common synthetic polymers used for fibrous meshes and porous scaffolds include polyesters such as polylactide and polyglycolide and their copolymers, polycaprolactone, and polyethylene glycol. Synthetic polymers have advantages over natural polymers in select instances, such as the following i... 

Sun, H., Qu, Z., Guo, Y., Zang, G., Yang, B. In vitro and in vivo effects of rat kidney vascular endothelial cells on osteogenesis of rat bone marrow mesenchymal stem cells growing on polylactide-glycoU acid (PLGA) scaffolds. Biomed. Eng. Online 6,41 (2007)... 

Cao, Y., T.I. Croll, J.J. Cooper-White, A.J. O Connor, and G.W. Stevens. 2003. Production and surface modification of polylactide-based polymeric scaffolds for soft-tissue. Biopolym Methods Tissue Eng 238 87. 

FIGURE 13.9 FTIR spectra of porous 8S IS polylactide-glycolide scaffold incutiaied in simulated physiological fluid (SPF) for various times (7 = 0-16 days). The spectra show the development of phosphate ( ) and carbonate (A) peaks as incubation time increases. Peaks lepiesenting polymer (o) are also indicated. (From Murphy et al 2000a, with permission.)... 

FIGURE 13.10 Cumulative release of vascular endothelial growth factor (VEGF) from mineralized (X) and nonmineralized ( ) porous polylactide-glycolide scaffolds. Values represent the mean and standard deviation of five samples. (From Murphy et al., 2000c, with permission.)... 

Cell-culture studies have indicated that such structures promote cellular infiltration into the fibrillar network and can become densely populated in a reasonably short time. A number of natural and synthetic polymers have been successfully electrospun into fibrous scaffolds for the purpose collagen, elastin, gelatin, fibrinogen, polyglycolic acid, polylactic acid, polycaprolactone, polylactide-co-glycolide and polylactide-co-caprolac-tone. Recently published work indicates that an electrospun web formed... 

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