In Vivo Biodegradability of PLLA and PLGA Sponge using Non-toxic Effevescent as a Porogen Additive

Cho, Yong Cheol; Rhie, Jong Won; Park, Jae Gu; Kim, Sun Ok; Byun, Jun Hee; Moon, Duc Soo; Jung, Yeon Hee; Ju, Young Min; Han, Dong Keun

Abstract

In many tissue engineering application, highly open porous scaffolds are required for efficient cell seeding and culture. Synthetic biodegradable polymers such as poly (L-lactic acid)(PLLA) and its copolymers with D-lactic and glycolic acids(PLGA) are widely used as a porous scaffold. The suitable biodegradability and dimensional stability of porous scaffolds during in vivo implantation play an important role in tissue engineering application. In this study, we investigated in vivo biodegradation and dimensional stability of acellular porous polymer scaffolds prepared by using a gas foaming technique with non-toxic effervescent mixture. In addition, we have engineered cartilage tissue 3D cultured on PLGA scaffolds in nude mouse in order to compare with degradation and deformation on acellular porous polymer scaffolds and to form tissue-engineered cartilage tissue. Sodium bicarbonate and citric acid crystals were used as an effervescent mixture. These particles were milled and sieved to yield various range of sizes(50 - 100, 100 - 300, and > 300 micrometer). After polymer scaffolds fabricated, biodegradation test was performed in subcutaneous tissue of male rats during 12 weeks. Degradability of polymer scaffolds were evaluated by weight difference, gel permeation chromatography(GPC), and SEM as each period. Tissue-engineered cartilage by transplanting 3D cultured chondrocytes onto PLGA 85:15 scaffolds in nude mouse was also made and compared with acellular scaffolds. In conclusion, highly open porous biodegradable scaffolds are prepared by gas foaming method using sodium bicarbonate and citric acid as a non-toxic effervescent mixture. Furthermore, tissue-engineered cartilage formation by in vivo 3D culture onto modified PLGA scaffolds in nude mouse was significantly improved as compared to controls.