Electrospinning and melt electrowriting of a tunable triblock-copolymer composed of poly(ε-caprolactone) and poly(L-lactic acid) for biomedical applications

Abstract

Both electrospinning (ES) and melt electrowriting (MEW) garner emerging interest within the field of biomedical applications. Poly(ε-caprolactone) (PCL) is still the gold standard for both techniques, demonstrating excellent processability due to its solubility, melt flow properties and thermal stability. However, when evaluating biomaterials for soft tissue applications, PCL exhibits limitations such as low elasticity and extended biodegradation times. Additionally, the limited availability of materials that are processable by MEW constrains their broader clinical translation. To address this limitation, a tunable triblock-copolymer of PCL and poly(L-lactic acid) (PLLA) is synthesized and processed using ES and MEW. This synthesis employs a PCL-diol backbone with a molar mass of 30 000 g mol-1, to which various lengths of PLLA end-blocks are added on both termini (PLLA-b-PCL-b-PLLA). The successful incorporation of these tunable end-blocks is verified through spectroscopic analysis. The ES of PLLA-b-PCL-b-PLLA reveals excellent fiber formation, with fiber diameters ranging between 2–4 µm as the PLLA molar mass increases. The tunable nature of the polymer allows for MEW at 90 °C, producing fibers with diameters ranging between 40–50 µm. Additionally, the materials exhibit adjustable mechanical properties and biodegradation rates by varying the PLLA segment lengths. Finally, in vitro cell testing using MC3T3-E1 cells demonstrates the polymer's excellent biocompatibility.