Porous polylactide/chitosan scaffolds for tissue engineering

Abstract

Novel porous scaffolds were fabricated using biodegradable polylactide/chitosan blends. A combinational technique involving solvent-extracting, liquid-solid separation, and freeze-drying paths were employed. The processing parameters were optimized in order to produce desired porous scaffolds and thus obtained scaffolds showed well distributed and interconnected porous structures with controllable porosities varying from around 50-85% and regulative pore sizes being distributed within a region between 2 and 190 microm. These scaffolds exhibited remarkably improved hydrophilicity based on the measurements for their swelling index. The results obtained from in vitro incubation of scaffolds in phosphate buffered saline solutions at 37 degrees C during various periods up to 10 weeks indicated that chitosan component inside the scaffolds, on the one hand, effectively buffered the acidic degradation products of polylactide/chitosan scaffolds and on the other hand, the degradation of the scaffolds was also conspicuously delayed. These porous scaffolds maintained well-defined compressive mechanical properties and by well-blending polylactide with chitosan component, improved toughness on the resultant porous scaffolds was also observed.

Mechanical Properties of Porous Polylactide/Chitosan Blend Membranes

“…[26] In addition, these blends have been further fabricated into porous scaffolds for the applications in tissue engineering. [27] It is generally accepted that biodegradable porous scaffolds provide not only a desirable three-dimensional environment within which cells attach, proliferate and differentiate, but also a reliable mechanical support for the regenerated tissue to finally reach its stable structure. [28,29] The mechanical properties of scaffolds, especially, the mechanical characteristics in a wet biomechanical environment, thus become an important issue for their applications.…”

“…[26,27] In brief, chitosan was first dissolved in 1.0 vol.-% acetic acid aqueous solution to prepare 1.0 wt.-% chitosan solutions. In the case of porous PDLLA/chitosan membranes, a certain amount of acetone was slowly introduced into a chitosan solution with vigorous stirring, followed by adding 2% (w/v) PDLLA solution in acetone dropwise with additional stirring.…”

“…[27] The porous membranes were cut into strips and viewed using SEM (Philips, XL-30) for their morphologies. The pore-size intervals were estimated from SEM micrographs.…”

Evaluation of poly(L-lactide) and chitosan composite scaffolds for cartilage tissue regeneration

“…The distribution of the pores within the scaffolds varied significantly. [21,22] The shapes of the pores were not uniform (irregular shaped).…”

“…This can be accounted to the fact that chitosan molecules are more hydrophilic in nature as compared to the PLLA polymer chains. [40] The swelling profiles of the scaffolds were fitted to Peleg's water sorption model (Figure 4(b)) (Equation (6)). [41] Peleg's rate constant (K 1 ) and Peleg's capacity constant (K 2 ) are calculated from the initial duration of the swelling profiles.…”