Fabrication of poly(l-glutamic acid)/chitosan polyelectrolyte complex porous scaffolds for tissue engineering

Porous scaffolds composed of polypeptides and polysaccharides have remarkable biocompatibility and potential to mimic an extracellular matrix for tissue engineering. This study presented a novel design of polyelectrolyte complex porous scaffolds of a synthetic polypeptide poly(l-glutamic acid) (PLGA) and a natural polysaccharide chitosan (CS) using a freeze drying method. The microstructure of the porous scaffolds could be adjusted by changing the freezing temperature and solid content of the reacting polymer. PLGA/CS scaffolds fabricated from 2% solid content and at a freezing temperature of -20 °C exhibited an interconnected porous structure with average pore size between 150 and 200 μm. The contact angle of less than 75° and high swelling ratio of more than 700% showed the excellent hydrophilic performance of these scaffolds. Degradation of the PLGA/CS composite scaffolds could be modified and more CS content contributed a higher resistance to biodegradation. The mechanical properties of the scaffolds could be controlled by varying the PLGA/CS molar ratio and solid content. The scaffolds exhibited good elastic behavior in wet state. In vitro culture of rabbit adipose-derived stem cells (ASCs) indicated that the selected PLGA/CS porous scaffolds supported cell attachment and growth. In summary, the PLGA/CS porous scaffolds show excellent properties, such as an interconnected porous structure, mechanical strength, hydrophilicity, biodegradability and biocompatibility. The successful repair of articular cartilage defects showed the potentiality of using PLGA/CS scaffolds in cartilage tissue engineering.