Advances in 3D and 4D Printing for Personalized Medicine: Smart Materials, Implants and Drug Delivery Systems

Biological engineering has seen fundamental changes through rapid 3D and 4D printing technology development, with applications in pharmaceutical creation and individual medicine therapy. The review provides essential information about core principles of 3D and 4D printing as well as materials and procedural aspects and application of these technologies to design and manufacture individualized drug delivery systems (DDSs), smart implants and adaptive therapeutic platforms. Complex DDSs emerge from FDM printing paired with SLS technology and combined with SLA processes to enable precise drug release profile management. Smart polymers, including PLGA–PEG–PLGA and Pluronic F-127, are useful for their stimuli-responsive capabilities that allow controlled release DDSs incorporated with bioinks, allowing scientists to develop biocompatible patient-specific implants together with biosensors and scaffolds. 4D printing adds time-responsive adaptability as an additional dimension that enables structures made through printing to develop dynamic changes through external triggers like temperature changes and light cues and pH variations. Progress in this field now enables researchers to develop medical implants that can heal themselves and drug carriers with built-in shape memory effects as well as bioresponsive medical devices. Several barriers such as regulatory obstacles and scalability problems together with material constraints still need resolution before this technology can achieve its full clinical potential. A comprehensive evaluation addresses present development in addition to future market opportunities while exploring difficulties of 3D and 4D printing applications in biomedical fields that drive modern healthcare transformations.