Characterization of compressive deformation behavior and biocompatibility of bioabsorbable layered PLLA scaffolds

Development of scaffolds with porous structures for cell seeding and growth has been one of the most important issues in tissue engineering. Typical biodegradable polymer PLLA is widely utilized for such scaffolds due to biodegradability and biocompatibility. When PLLA scaffolds are used for regeneration of bone tissue, it is preferable that they have mechanical compatibility with the bone tissue to be regenerated. However, the mechanical properties of porous PLLA structures tend to be much lower than those of the bone tissue. In the present study, therefore, a new concept for PLLA scaffold, called layered structure, was introduced to improve the mechanical properties. Experimental results showed that the elastic modulus and strength under compression were effectively improved due to the layered structure. Deformation mechanism for catastrophic failure in the layered scaffold was found to be buckling of the outer layer, while in the standard scaffold, such critical mechanism of deformation was micro-buckling of the wall structures surrounding pores. It was also found that MC3T3-E1 cells well adhered to the surface regions of the scaffolds.