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- Functionalization and photocuring of an L-lactic acid macromer for biomedical applicationsPublication . Marques, Dina; Santos, João; Ferreira, Paula; Correia, Tiago R.; Correia, Ilídio Joaquim Sobreira; Gil, Maria; Baptista, Cristina Maria dos Santos GaudêncioL-lactic acid was the starting material for obtaining bioahesives. Reaction with 1,4-butanediol provided a telechelic lactic acid prepolymer with hydroxyl end groups further functionalized with 2-isocyanatoethyl methacrylate. Films were produced upon UV irradiation, 2 min, after addition of Irgacure 2959. This was a solvent and catalyst free process. Thermal characterization of films confirmed stability at physiological temperature, enabling photocuring. Adhesion properties were assessed with good results. In vitro degradation tests showed moderate hydrolytic instability dependent on thickness. SEM images revealed a uniform and compact structure. Thrombosis tests confirmed the materials’ thrombogenicity while biocompatibility experiments showed fibroblast viability and antimicrobial behavior.
- Engineering star-shaped lactic acid oligomers to develop novel functional adhesivesPublication . Santos, João; Travassos, Diana Rita Sousa; Ferreira, Paula; Marques, Dina; Gil, Maria; Miguel, Sónia; Ribeiro, MP.; Correia, Ilídio Joaquim Sobreira; Baptista, CristinaDirect polycondensation of L-lactic acid with a comonomer allows tailoring the properties of the product from the very first step. The viscous L-lactic acid co-oligomers with star-shaped architectures obtained were modified with three different acrylate monomers. Regardless the functionalization agent, UV curing was fast and all materials were cell compatible and promoted cell adhesion. The physical properties of the three star-shaped films exhibited a consistent trend as swelling capacity, hydrolytic instability, and gel content decreased simultaneously. A higher network density increased crosslinking degree and gel content among the films with an isocyanate group. The methacrylic end group functionalized material, lowest molecular weight, consistently exhibited the higher hydrolytic instability. Comparison of physical properties of these films with the corresponding linear materials reported previously confirmed the influence of precursor molecular architecture on the final material. The methodology developed herein is prone to scale-up and lead to the industrial production of new bioadhesives.