Next-Generation Epidermal Patches: Bridging 3D and Multidimensional Printing for Biomedical and Cosmetic Innovation

Advances in printing technologies have revolutionized epidermal patch design by enabling precise control over architecture, material composition, and functional integration. These innovations have expanded applications in biomedical and cosmetic applications, facilitating personalized and adaptive solutions in drug delivery, wound healing, tissue regeneration, and aesthetics. This review provides a comprehensive overview of 3D-printed epidermal patches, encompassing both conventional (non-microneedle) and microneedle-integrated platforms. Particular emphasis is given to innovative materials such as self-oxygenating hydrogels and nanomaterial-free bioinks based on proteins and polysaccharides, alongside nanocomposite variants. We discuss 3D printing techniques for acellular constructs, cell-laden matrices, and microneedle array patches (MAPs), as well as emerging multidimensional 4D and 5D strategies. 4D printing enables dynamic, stimuli-responsive constructs with self-healing capacity, adaptability, and controlled drug release, while 5D printing enhances design complexity, mechanical strength, and biomimicry, yielding more durable and versatile patches. Biomedical applications explored include dermal and transdermal drug delivery, with particular focus on insulin delivery in diabetes management, wound repair, regenerative therapies, photodynamic interventions, and biosensing. Moreover, we discuss integrated printed patches with wearable sensors, smart devices, and artificial intelligence (AI), which represents a transformative frontier in personalized cosmetics, enhancing product efficacy and consumer satisfaction in both ingredient use and formulation design. Finally, we address clinical translation, regulatory challenges, and commercialization prospects, aiming to guide researchers, clinicians, and industry stakeholders in advancing hydrogel-based additive manufacturing from concept to real-world clinical and cosmetic solutions.