Concept Design of Transdermal Microneedles for Diagnosis and Drug Delivery: A Review

Microneedles (MNs) are one of intriguing approach for efficient transdermal drug delivery that penetrates the protective skin barrier in a painless and less invasive way. In recent years, multidisciplinary studies have been conducted to improve their properties to meet stringent requirements and obtain market release approval. This review aims to summarize the latest concept design with unique properties in the advancement of transdermal MNs for diagnosis and therapeutic application. Numerous significant innovation strategies in improving MNs in aspects of adhesion ability, dosing capacity, drug-controlled release, diffusion control ability, site-targeted and on-demand drug delivery, and biomarker or drug release monitoring are presented. Given that the majority of technologies used in such design are exclusively laboratory-based, striving toward commercialization is a critical aspect of the revolution. Key challenges and future perspectives in industrial and economic aspects are identified with the intention of translating the reviewed technologies into marketable products.