Enzymatically catalyzed poly(butylene succinate)(PBS) copolymers as building blocks for degradable scaffolds

Abstract

Event Abstract Back to Event Enzymatically catalyzed poly(butylene succinate)(PBS) copolymers as building blocks for degradable scaffolds Miroslawa El Fray1, Monika Malesa1 and Aleksandra Kaczmarek1 1 West Pomeranian University of Technology Szczecin, Biomaterials and Microbiological Technologies, Poland Introduction: An increasing exploitation of regenerative potential of living tissues is observed from last two decades since temporary, biodegradable polymeric templates (scaffolds) are being developed for tissue engineering[1]. Biodegradable polymers are synthesized from non-toxic monomers, but toxic catalysts are frequently used like in case of biodegradable aliphatic polyesters where highly toxic tin compounds are used[2]. Therefore, stiff but biodegradable polymers are needed for tissue engineering and other biomedical applications. In our work we focus on much safer enzymatic biocatalysts which are proposed for the synthesis of aliphatic polyester, poly(butylene succinate)(PBS) and its copolymers. Materials and Methods: Poly(butylene succinate)(PBS) and its copolymers containing ethylene glycol sequences (PBS-EG) and dilinoleic acid sequences (PBS-DLA) were prepared by enzymatic polymerization of succinic acid ester (diethyl succinate)(DES), 1,4-butanediol (1,4-BD) and poly(ethylene glycol) (PEG_3000) or dilinoleic acid (DLA) in organic solvent (diphenyl ether). Lipase B derived from Candida antarctica strain, trade name Novozym 435th (N435), was used as a catalyst. The hard segments (PBS) to soft segments (EG or DLA) ratio based on stoichiometric calculations was 50:50 wt%. The reaction mixture was dissolved in chloroform to remove the unreacted monomers and impurities and then the microspheres in which the enzyme catalyst was immobilized were separated. Samples chemical structure were assessed by using ATR-FTIR and NMR analysis, degradation and contact angle measurement. Sample mechanical characterization was performed by tensile test. Preliminary cell viability tests have been performed by using fibroblasts. Results and Discussion: The PBS-EG and PBS-DLA copolymers were synthesized using Candida Antarctica from lipase B. Analysis of chemical structure with 1H NMR and ATR FT-IR spectroscopy confirmed the presence of specific bonds and groups, characteristic for ester and ether groups. The contact angle measurements on both materials revealed differences in hydrophilicity thus indicating that depending from the nature of copolymer building block, degradation profile can be adjusted. This can be achieved along with mechanical properties changes since PBS-DLA copolymer showed to be more flexible as compared to PBS-EG. Positive results from the preliminary cell viability tests have been also obtained. Conclusions: Enzymatically catalyzed copolymers of poly(butylene succinate), namely PBS-EG and PBS-DLA has been obtained. Results showed that these materials have different surface and mechanical properties depending from the chemical structure of soft segment building block. Their degradation profile and mechanical properties can also be adjusted thus making them an interesting candidate for degradable scaffolds, specifically for heart tissue engineering. This work was supported by the National Science Centre under the HARMONIA scheme (UMO-2014/14/M/ST8/00610).