Microneedle-based biosensing

Microneedles (MNs) are microscopic needles that are applied to the skin in a minimally invasive way to facilitate transdermal drug delivery and/or uptake of interstitial fluid from the skin, which contains a variety of metabolites that can serve as biomarkers. The collection of interstitial fluid can be followed by post-sampling analysis or in situ real-time biosensing for disease diagnosis and drug monitoring. The painless and easy administration of MNs is appealing to patients, especially for long-term monitoring. In this Review, we discuss the use of MNs for biosensing purposes. We highlight the different types of MNs and sensing technologies used to develop MN-based biosensors. In addition, we discuss the potential to integrate MNs with wearable devices for real-time monitoring to improve point-of-care testing. Finally, we review the translational hurdles to be considered in bringing this technology from benchtop to bedside. Microneedles are an effective tool for the collection of interstitial fluid in a minimally invasive manner. Coupling microneedles with biosensors would allow for deep tissue sensing and fast continuous monitoring. This Review discusses the capabilities of microneedles for analyte sampling and further analysis, the development of microneedle-based biosensors for disease and drug monitoring, and the clinical translation potential.