The advantages of microneedle patches compared to conventional needle-based drug delivery and biopsy devices in medicine

Microneedle (MN) patches are composed of micron-sized needles organised in arrays and attached to the backing of a patch. The most common type is the transdermal patch, designed to uniformly penetrate the stratum corneum to reach the dermis of the skin. Recent advances in 3D printing technology have allowed the development of reproducible, efficient methods to create microneedles on a large scale, which had previously been a factor in the limited clinical uptake. In comparison to conventional drug delivery methods, MN patches have been shown to significantly reduce pain and scar generation while maintaining effective and reliable delivery of vaccines, immunotherapies, and slow-release drug therapies. The MN design has also been investigated as an alternative to conventional tissue biopsy, with positive results. Synchronous delivery of medications while monitoring biomarkers in dermal interstitial fluid (ISF) is also a promising clinical development with wide-reaching benefits. MNs are diverse in design and material composition, and with developments in fabrication technology, transdermal drug delivery has been applied to many clinical fields, including chronic illnesses such as arthritis or diabetes, cancer, immunotherapies, epidemic disease prevention and ocular treatments. While the majority of MN patch applications are still in the pre-clinical testing phase in animal models, further translation of this technology to the clinic could aid in medication and vaccine compliance, improve treatment access in rural and remote communities, improve targeted therapy applications and provide financial cost savings to the public health sector. This review evaluates the designs and applications of current transdermal MN patches for drug delivery, biomarker monitoring and diagnostic biopsies compared to conventional needle-based methods.