Central airway obstruction is a life-threatening disorder causing a high physical and psychological burden to patients. Standard-of-care airway stents are silicone tubes, which provide immediate relief but are prone to migration. Thus, they require additional surgeries to be removed, which may cause tissue damage. Customized bioresorbable airway stents produced by 3D printing would be highly needed in the management of this disorder. However, biocompatible and biodegradable materials for 3D printing of elastic medical implants are still lacking. Here, we report dual-polymer photoinks for digital light 3D printing of customized and bioresorbable airway stents. These stents exhibit tunable elastomeric properties with suitable biodegradability. In vivo study in healthy rabbits confirmed biocompatibility and showed that the stents stayed in place for 7 weeks after which they became radiographically invisible. This work opens promising perspectives for the rapid manufacturing of the customized medical devices for which high precision, elasticity, and degradability are sought.

Central airway obstruction is a life-threatening disorder causing a high physical and psychological burden to patients due to severe breathlessness and impaired quality of life. Standard-of-care airway stents are silicone tubes, which cause immediate relief, but are prone to migration, especially in growing patients, and require additional surgeries to be removed, which may cause further tissue damage. Customized airway stents with tailorable bioresorbability that can be produced in a reasonable time frame would be highly needed in the management of this disorder. Here, we report poly(D,L lactide-co-ε-caprolactone) methacrylate blends based biomedical inks and their use for the rapid fabrication of customized and bioresorbable airway stents. The 3D printed materials are cytocompatible and exhibit silicone-like mechanical properties with suitable biodegradability. In vivo studies in healthy rabbits confirmed biocompatibility and showed that the stents stayed in place for 7 weeks after which they became radiographically invisible. The developed biomedical inks open promising perspectives for the rapid manufacturing of the customized medical devices for which high precision, tuneable elasticity and predictable degradation are sought after.

and chemical stability, and applicability to a vast range of scaffold materials. Indeed, salt templates have been used to achieve porosity in a wide variety of scaffold materials, including natural polymers such as silk fibroin, [7] synthetic polymers such as poly(l-lactic acid), [8] bulk metallic glasses, [9] crystalline metals such as aluminum, [10] and even magnesium, which is known for its high chemical reactivity. [11] In these examples, the pore size of the final scaffold is defined by the size of the original salt particles or the salt aggregates used as template.For all of these porous scaffolds, the salttemplating approach has led to random porosity with broad pore-size distributions. [6,8,11] This reflects the polydisperse nature of the templating salt particles and limits our ability to control the porous architecture of the final scaffold. By contrast, recent advances in additive manufacturing (AM) have added freedom of design to the manufacturing of porous materials, opening the possibility to create architectured gridlike structures with well-controlled porosity and pore sizes at the macroscale. [5,[12][13][14][15] While the pool of materials printable by AM is extending rapidly, [16,17] materials that possess a high chemical reactivity remain a challenge to shape using additive technologies. Among such reactive materials, magnesium (Mg) is receiving increasing attention as a metallic biodegradable implant material for temporary bone replacement or osteosynthesis. [18][19][20] This stems from its similarity in mechanical properties to bone, and its ability to induce new bone formation [21,22] while also being bioresorbable. [23] It is widely accepted that pore size, [24][25][26] shape, [27][28][29] directionality, [30,31] and degree of porosity [24,32,33] strongly influence cell viability and growth. To guide bone-tissue growth, large open porosity with pore sizes >300 µm in combination with surface roughness appears to be most successful. [24,34] Thus, the ability to shape Mg into structures with controlled porosity and pore size in a patient-specific geometry is highly desired.Staiger et al. [35] and Nguyen et al. [36] previously reported a three-step process for indirect AM of Mg by printing first a polymer that was then infiltrated with an NaCl paste. The latter served, upon removal of the polymer, as a template for Mg infiltration. While being an important first approach to structuring Mg using AM, the additional processing step required to generate first the polymer template resulted in imperfect structure replication and was limited to geometries that allow NaCl infiltration into the template.Porosity is an essential feature in a wide range of applications that combine light weight with high surface area and tunable density. Porous materials can be easily prepared with a vast variety of chemistries using the salt-leaching technique. However, this templating approach has so far been limited to the fabrication of structures with random porosity and relatively simple macroscopic shapes. Here, a ...

Structural color is frequently exploited by living organisms for biological functions and has also been translated into synthetic materials as a more durable and less hazardous alternative to conventional pigments. Additive manufacturing approaches were recently exploited for the fabrication of exquisite photonic objects, but the angle-dependence observed limits a broader application of structural color in synthetic systems. Here, we propose a manufacturing platform for the 3D printing of complex-shaped objects that display isotropic structural color generated from photonic colloidal glasses. Structurally colored objects are printed from aqueous colloidal inks containing monodisperse silica particles, carbon black, and a gel-forming copolymer. Rheology and Small-Angle-X-Ray-Scattering measurements are performed to identify the processing conditions leading to printed objects with tunable structural colors. Multimaterial printing is eventually used to create complex-shaped objects with multiple structural colors using silica and carbon as abundant and sustainable building blocks.

Vat photopolymerization 3D printing provides new opportunities for the fabrication of tissue scaffolds and medical devices. However, for the manufacturing of biodegradable elastomers, it usually requires the use of organic solvents to dissolve the solid photoinitators and achieve low resin viscosity, making this process environmentally unfriendly and not optimal for biomedical applications. Here, we report solvent-free 3D printing of biodegradable elastomers by digital light processing with well-defined photoinitiator–polymer conjugates. Being in liquid state at room temperature, the macrophotoinitiators enabled high-quality 3D printing in the absence of any organic solvents that are usually used in digital light 3D printing. This allowed the systematic investigation of structure–property relationships of 3D-printed biodegradable elastomers without the interference from reactive diluents. The developed macrophotoinitiators were compatible with various photopolymers and could be applied for solvent-free fabrication of biodegradable shape-memory devices. This work offers new perspectives for the solvent-free additive manufacturing of bioresorbable medical implants and other functional devices.