Biomaterials

Today’s medicine requires bio-absorbable polymeric biomaterials that present thermoplastic elastomer (TPE) behavior, for their application as medical devices or scaffolds for soft tissue engineering. Among the most investigated polymers used as biomaterials, poly (glycolic acid) (PGA) and poly (lactic acid) (PLA) can be mentioned. These polyesters are however glassy at body temperature and mechanically brittle, so copolymerization with other monomers is a strategy to obtain TPEs with tuned biodegradation rate and mechanical properties. In a search of new polymeric biomaterials with TPE behavior, various lactones and macro lactones, most of them were employed previously by the chemical industry and cosmetics, which draw our attention. Among the cyclic esters, the following ones can be mentioned: β-propiolactone (β-PL), γ-butyrolactone (γ-BL), γ-valerolactone (γ-VL), δ-valerolactone (δ- VL), δ-methyl-ε-caprolactone, decalactones such as γ-decalactone (γ-DL), δ-decalactone (δ-DL) or ε-decalactone (ε-DL) (with rings of 5, 6 or 7 members respectively), ω-pentadecalactone (PDL), hexadecalactone or ethylene brassylate. Moreover, p-dioxanone or trimethylene carbonate may also be of interest. The mentioned substances are monomers that can be synthesized by ring opening polymerization on their own or on the dimmer (lactide and glycolide). In this work TPE copolymers of either high glass transition temperature (Tg) (>20ºC ) or low Tg (between -65 and 0ºC) are synthesized and characterized in terms of molecular parameters, physical, chemical and mechanical properties and biodegradation. In the former case, copolymers of lactide with other co-monomers are proposed in order to reduce the melt temperature and crystallization capability of polylactide. In the latter, alternative copolymers will be introduced for poly (ε-caprolactone). This is because polymers of high Tg present low ductility, brittleness and too high stiffness for soft tissue applications. Those of low Tg, however, though excellent in the combination of mechanical properties for soft tissue engineering and devices, present often too low biodegradation rates.

 

 

 

 

Recent Publications:

1. Jose R Sarasua, Etxeberria A and Fernández J (2016) Synthesis and properties of ω-​pentadecalactone-​co-​δ-hexalactone copolymers: A biodegradable thermoplastic elastomer as an alternative to poly (ε-​caprolactone). Rsc Advances 6: 3137-3149.
2.  Jose R Sarasua, Fernández J, Amestoy H, Larrañaga-Varga A, Sardon H and Aguirre M (2016) Effect of molecular weight on the physical properties of poly (ethylene brassylate) homopolymers J Mech Behav Biomed Mater 64: 209-219.
3. Jose R Sarasua, Fernández J, Larrañaga A and Etxeberria A (2016) Ethylene brassylate-co-δ-hexalactone biobased polymers for application in the medical field: Synthesis, characterization and cell culture studies. Rsc Advances 6: 22121-22136.
4. Jose R Sarasua, Fernández J, Larrañaga A and Etxeberria A (2014) Tensile behavior and dynamic mechanical analysis of novel poly (lactide/d-valerolactone) statitical copolymers. J. Mech. Behav. Biomed Mater 35: 39-50.
5. Jose R Sarasua and Larrañaga A (2016) Poly (α-hydroxy Acids)-based cell microcarriers. Applied Sciences 6(436): 1-16.