Advances in 4D printing of biodegradable photopolymers

Abstract

Over the past decade, 4D printing has revolutionized the field of advanced manufacturing by fabricating structures that dynamically respond to environmental stimuli. During this process, shape-memory polymers (SMPs) stand out, enabling transformations triggered by temperature, light, or other environmental factors, and show great potential for applications in biomedicine and beyond. Notably, biodegradable SMPs offer a compelling advantage in medical devices due to their ability to adapt within the body's temperature range and to be absorbed by tissues, reducing the risks associated with permanent implants. While extrusion techniques have laid the groundwork for 4D printing in biomedicine, vat photopolymerization methods like stereolithography and digital light processing are now at the forefront, favored for their high printing resolution and flexibility in material design. However, the search for suitable biodegradable materials for these advanced techniques continues, with current research focusing on developing systems that meet both the mechanical demands and degradation profiles required for medical applications. This review aims to critically analyze the advancements in biodegradable 4D photopolymers, particularly biodegradable elastomers, and discuss the challenges that lie ahead for their clinical translation.