Bioinspired microneedle patches: Biomimetic designs, fabrication, and biomedical applications

Nature contains abundant systems that can significantly alter their structures and properties to adapt to the surrounding environment. Through natural selection and unceasing evolution, hierarchical architectures and sophisticated strategies have been created by nature to achieve optimally adapted materials for biomedical applications. The development of microneedles (MNs) has advanced to the next generation of bioinspired MNs (BMNs), with the goal of improving functions such as amelioration of mechanical properties and tissue adhesion. The biomimetic designs and structures of MNs are highlighted in the present review. This is followed by an in-depth discussion of the fabrication approaches from molding techniques to 3D and 4D printing. The medical applications of BMNs, including drug delivery, regenerative medicine, biopsy sampling, and biosensing, are also discussed. Last, future opportunities and challenges with respect to clinical translation are also deliberated.