Hydrogel‐Forming Microneedles: Current Advancements and Future Trends

In this focused progress review, the recent developments and trends of hydrogel‐forming microneedles (HFMs) and potential future directions are presented. Previously, microneedles (solid, hollow, coated, and dissolving microneedles) have primarily been used to enhance the effectiveness of transdermal drug delivery to facilitate a wide range of applications such as vaccinations and antibiotic delivery. However, the recent trend in microneedle development has resulted in microneedles formed from hydrogels which have the ability to offer transdermal drug delivery and, due to the hydrogel swelling nature, passively extract interstitial fluid from the skin, meaning they have the potential to be used for biocompatible minimally invasive monitoring devices. Thus, in this review, these recent trends are highlighted, which consolidate microneedle design considerations, hydrogel formulations, fabrication processes, applications of HFMs and the potential future opportunities for utilizing HFMs for personalized healthcare monitoring and treatment. This review focuses on the current trends of the recently developed hydrogel‐forming microneedles (HFMs). In which the microneedle design, fabrication methods, materials used, and applications of HFMs are all discussed. The advantages and current drawbacks of these technologies as well as the potential future directions for the use in a healthcare setting are also explored.