Volumetric Printing of Thiol‐Ene Photo‐Cross‐Linkable Poly(ε‐caprolactone): A Tunable Material Platform Serving Biomedical Applications

• Published in: Advanced materials (Weinheim) 2023-05, Vol.35 (19), p.e2210136-n/a
• Main Authors: Thijssen, Quinten, Quaak, Astrid, Toombs, Joseph, De Vlieghere, Elly, Parmentier, Laurens, Taylor, Hayden, Van Vlierberghe, Sandra
• Format: Article
• Language: English
• Subjects: Acrylates; Biocompatibility; Biocompatible Materials - chemistry; Biomedical materials; computed axial lithography; Humans; Materials science; Mechanical properties; poly(ε‐caprolactone); Printing, Three-Dimensional; Thermodynamic properties; thiol‐ene; Three dimensional printing; tissue engineering; Tissue Engineering - methods; volumetric 3D‐printing
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202210136

Current thoroughly described biodegradable and cross‐linkable polymers mainly rely on acrylate cross‐linking. However, despite the swift cross‐linking kinetics of acrylates, the concomitant brittleness of the resulting materials limits their applicability. Here, photo‐cross‐linkable poly(ε‐caprolactone) networks through orthogonal thiol‐ene chemistry are introduced. The step‐growth polymerized networks are tunable, predictable by means of the rubber elasticity theory and it is shown that their mechanical properties are significantly improved over their acrylate cross‐linked counterparts. Tunability is introduced to the materials, by altering Mc (or the molar mass between cross‐links), and its effect on the thermal properties, mechanical strength and degradability of the materials is evaluated. Moreover, excellent volumetric printability is illustrated and the smallest features obtained via volumetric 3D‐printing to date are reported, for thiol‐ene systems. Finally, by means of in vitro and in vivo characterization of 3D‐printed constructs, it is illustrated that the volumetrically 3D‐printed materials are biocompatible. This combination of mechanical stability, tunability, biocompatibility, and rapid fabrication by volumetric 3D‐printing charts a new path toward bedside manufacturing of biodegradable patient‐specific implants. Thiol‐ene cross‐linkable poly(ε‐caprolactone) is introduced and the effect of the cross‐link density on the networks’ physico‐chemical properties, volumetric printability, and biocompatibility is investigated. Notably, this is the first report on volumetric 3D‐printing of polyesters and 3D‐printing of the smallest features to date, for non‐acrylate‐based resins, is illustrated.