Degradable 4D-printed hydration-driven actuators from a single family of amphiphilic star-shaped copolymers

• Published in: Materials & Design 2024-05, Vol.241, p.112953, Article 112953
• Main Authors: Grosjean, Mathilde, Schmidleithner, Christina, Dejean, Stéphane, Larsen, Niels B., Nottelet, Benjamin
• Format: Article
• Language: English
• Subjects: 4D printing; Actuator; Biochemistry; Biochemistry, Molecular Biology; Dual material printing; Life Sciences; Numerical modeling; star PEG-PLA copolymer; Stereolithography
• ISSN: 0264-1275; 0261-3069; 1873-4197; 0264-1275
• DOI: 10.1016/j.matdes.2024.112953

[Display omitted] •A single family of star-shaped poly(ethylene glycol)-poly(lactide) photopolymers is proposed to yield biocompatible degradable hydration-based actuators.•Dual-materials microstructures are designed and easily printed from two photopolymers resins by stereolitographic digital-light processing.•Modelled actuation is experimentally validated confirming the concept of actuators designed from degradable photopolymers of same nature but distinct swellings.•The similar nature of the two photopolymers ensures a cohesive interface for a rapid actuation in less than a minute. Actuators are largely used in biomedical applications in the presence of sensitive live cells or biomolecules, which makes actuators triggered by water uptake highly appealing. Dual-material printing and hydration driven expansion is a method of choice to produce such actuators, but mostly rely of non-degradable polymers or on the combination of polymers of different nature that may lead to interface incompatibilities. To overcome this challenge, we report here on two photocrosslinkable resins based on a single family of degradable hydrophilic or hydrophobic star-shaped poly(ethylene glycol)-poly(lactide) copolymers. The two materials are first printed individually and characterized to ensure that their properties enable the printing of dual material objects by stereolithographic digital-light processing. Dual-materials actuators are then printed by sequential switching of the hydrophobic and hydrophilic resin baths. Objects of simple and complex shapes are easily obtained and exhibit rapid actuation (