polymers Article Study of the Influence of PCL on the In Vitro Degradation of Extruded PLA Monofilaments and Melt-Spun Filaments Vivien Barral 1, * , Sophie Dropsit 2 , Aurélie Cayla 1 , Christine Campagne 1 and Éric Devaux 1   Citation: Barral, V.; Dropsit, S.; Cayla, A.; Campagne, C.; Devaux, É. Study of the Influence of PCL on the In Vitro Degradation of Extruded PLA Monofilaments and Melt-Spun Filaments. Polymers 2021, 13, 171. https://doi.org/10.3390/polym 13020171 Received: 23 November 2020 Accepted: 30 December 2020 Published: 6 January 2021 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional clai- ms in published maps and institutio- nal affiliations. Copyright: © 2021 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 ENSAIT, GEMTEX—Laboratoire de Génie et Matériaux Textiles, F-59000 Lille, France, 2 Allée Louise et Victor Champier, 59056 Roubaix CEDEX 1, France; aurelie.cayla@ensait.fr (A.C.); christine.campagne@ensait.fr (C.C.); eric.devaux@ensait.fr (É.D.) 2 MATERIA NOVA—R&D CENTER, Avenue Nicolas Copernic 3, 7000 Mons, Belgique; sophie.dropsit@materianova.be * Correspondence: vivien.barral@ensait.fr Abstract: This work presents the effect of a melt-spinning process on the degradation behavior of bioresorbable and immiscible poly(D,L-lactide) (PLA) and polycaprolactone (PCL) polymer blends. A large range of these blends, from PLA 90 PCL 10 (90 wt% PLA and 10 wt% PCL) to PLA 60 PCL 40 in increments of 10%, was processed via extrusion (diameter monofilament: ∅ ≈ 1 mm) and melt spinning (80 filaments: 50 to 70 μm each) to evaluate the impact of the PCL ratio and then melt spinning on the hydrolytic degradation of PLA, which allowed for highlighting the potential of a textile-based scaffold in bioresorbable implants. The morphologies of the structures were investigated via extracting PCL with acetic acid and scanning electron microscopy observations. Then, they were immersed in a Dulbecco’s Modified Eagle Medium (DMEM) media at 50 ◦ C for 35 days and their properties were tested in order to evaluate the relation between the morphology and the evolution of the crystallinity degree and the mechanical and physical properties. As expected, the incorporation of PCL into the PLA matrix slowed down the hydrolytic degradation. It was shown that the degradation became heterogeneous with a small ratio of PCL. Finally, melt spinning had an impact on the morphology, and consequently, on the other properties over time. Keywords: biodegradable polymers; polyesters; immiscible blend; extrusion; melt spinning 1. Introduction Nowadays, there is an emergent interest in degradable and bioresorbable polymers for their applications in the medical field, and especially for tissue engineering. They are classi- fied according to geometrical criteria: one-dimensional structures, such as surgical sutures and ligatures [1]; two-dimensional structures, such as hernia repair meshes and sewing rings for heart valves prosthesis [1]; three-dimensional structures, such as walled tubular constructs for vascular grafts and orthopedic implants [1]. A very famous application example is the development of absorbable stents [2,3]. For tissue regeneration, the chosen material has to satisfy many criteria, such as biocompatibility or full resorbability i.e., their degradation products have to be metabolized and excreted. Most of the used polymers for these kinds of applications are an aliphatic polyester, such as polycaprolactone (PCL) [4–6], polybutylene succinate (PBS) [7], polylactide (PLA) [2,5], polyglycolide (PGA) [5], and poly-3-hydroxybutyrate (PHB, P3HB) [8]. Some others display ether–ester functions, such as polydioxanone (PDS, PDO) or polyethylene glycol (PEG). All these polymers have good biocompatibility and are known to be fully bioresorbable with different kinetic degradation times in the body. The design of a 3D scaffold requires the structure itself to have an architecture that promotes the formation of native anisotropic tissue [9]; in other words, the structure has to act as a template for tissue growth by dictating the shape [1]. The structure must be a network of large interconnected pores or “macropores” with a minimum size of Polymers 2021, 13, 171. https://doi.org/10.3390/polym13020171 https://www.mdpi.com/journal/polymers