In vivo performance of bioabsorbable PLLA Poly (L, lactic acid) scaffolds for use in bone repair

Author(s)

Mariana Vitelo Xavier

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2022-04-25

Examining board members

Paulo Kharmandayan; Marcos Matias Motta; Rodrigo Pinto Gimenez; Adriano Fregonesi; Wan Ching An

• Advisor: Paulo Kharmandayan; Sara Feldman

Abstract

Background: In tissue engineering, the appropriate choice of biomaterial involves many factors such as its physical and chemical characteristics, production costs, type of application, durability, biocompatibility and others. A great variety of biomaterials have been used and the polymer poly (L, lactic acid) has been one of the most advantageous and used among them, but its value makes it expensive and difficult to produce. Thus, it is important to study the synthesis and reduction of production costs of these materials. Objective: Synthesize the PLLA developed by the Biofabrication Institute (Biofabris) in a Thematic Project (FAPESP Case No. 2008/57860-3), to analyze the biocompatibility of this biomaterial and also a comparison of the cost of producing the national biomaterial and the imported biopolymer. Methods: This is a bi-national project in two stages, the first one at the Medical School of Unicamp, with the objective of synthesizing, sterilizing and analyzing the production cost of the biomaterial. The second stage involves biocompatibility tests proposed in ISO 10993, at the of Medical Sciences of UNR Argentina, where the surgeries were performed in 16-20-week-old female New Zealand rabbits, according to the rules of the Ethics Committee on Animal Use number 44371/0028 with project name "1MED423- Bone or cartilage tissue engineering". Total of 12 rabbits were separated into 2 groups of 6 animals for studies at 6 and 9 months post-implantation and subdivided into groups, control (lesion without PLLA insertion) and PLLA group (lesion + PLLA). After each period, the animals were sacrificed, histological, histomorphometric, tomographic, blood and liver studies were performed to understand the biocompatibility. Results: The histological data revealed that the biomaterial did not generate exacerbated inflammatory response or fibrous capsule formation suggestive of foreign body reaction. Furthermore, the bone regeneration around the lesion reinforced the images seen on tomography, which showed results with significant differences between the control group and the implanted group, where the PLLA group at 6 months post-implantation showed an estimated proportion of 62% of bone regeneration, and the group without PLLA 30%, while the animals at 9 months (control and implanted), showed respectively 66% and 31%, maintaining the significant difference and promising results. When blood samples and serological studies of liver profile were analyzed, control and implanted animals did not show significant differences, showing that the degradation of the biomaterial and its inflammatory response did not change the hematological values and liver enzymes. Finally, comparing the costs for each gram of imported PLLA of R$11.49 and R$13.92 with the value obtained of R$8.43 for laboratory synthesized PLLA, a difference of R$3.06 is calculated between synthesized PLLA and imported PLLA (TCI America™?) and a difference of R$5.49 for laboratory synthesized PLLA compared to imported PLLA (ACROS Organic™?). Conclusion: Data show that the biomaterial is biocompatible and the cost of synthesized PLLA is lower than the import value of the polymerized biomaterial (AU)

• FAPESP's process: 17/03249-0 - Processing, characterization and performance in vivo of PLLA Poly (L, lactic acid) bioabsorbable scaffolds to bone repair application
• Grantee: Mariana Vitelo Xavier
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)