Current Research Progress in Polymeric Microneedles for Targeted Drug Delivery and Aesthetic Applications

The skin is the body’s largest organ, which protects the internal tissues and organs against external factors and has a prominent impact on how someone looks. Moreover, self-esteem, quality of life, general mental health, and social life are all highly affected by the external appearance of the skin. The stratum corneum (SC) is the skin’s outermost layer that develops the first barrier for targeted drug delivery; however, low drug absorption over the SC often makes it complicated to treat dermal disorders. Polymeric microneedles (MNs) have been constructed to solve dermal issues by piercing them into the SC with negligible pain and damage. Polymeric MNs for direct injection, in contrast to hypodermal injection, provide the benefits of mildness and painlessness and are often exploited to treat patients who have aesthetic needs. This review gives an overview of MNs, materials used for the construction of MNs, and aesthetic applications of MNs. Herein, MNs’ fabrication methods, the mechanism of drug release from MNs, and the measurement of MNs are also explored. Customized polymeric MNs enable personalized aesthetic treatment plans, but balancing the biocompatibility, biodegradability, and mechanical strength of polymeric MNs is a central challenge. This can be resolved by a combination of natural and synthetic polymers to formulate innovative hydrogel MNs.