4D Printing in Biomedical Engineering: Advancements, Challenges, and Future Directions

4D printing has emerged as a transformative technology in the field of biomedical engineering, offering potential for dynamic, stimuli-responsive structures with applications tissue drug delivery, medical devices, and diagnostics. This review paper provides comprehensive analysis advancements, challenges, future directions engineering. We discuss development smart materials, including polymers, shape-memory bio-inks, well various fabrication techniques employed, such direct-write assembly, stereolithography, multi-material jetting. Despite promising advances, several challenges persist, material limitations related to biocompatibility, mechanical properties, degradation rates; complexities arising from integration multiple resolution accuracy, scalability; regulatory ethical considerations surrounding safety efficacy. As we explore printing, emphasise need innovations, emerging personalised medicine, nanomedicine, bioelectronic devices. Interdisciplinary research collaboration between science, biology, agencies, industry are essential overcoming realising full engineering landscape.