The noninvasive sampling of dermal interstitial fluid (ISF) for the monitoring of clinical biomarkers is a greatly appealing area of research. The identification of molecular biomarkers in biological fluids has been accelerated with ‐omics analyses but remains limited in ISF because of its time‐consuming and complex extraction process. Here, the generation of microneedle (MN) patches made of superabsorbent acrylate‐based hydrogels for the rapid sampling of dermal ISF is described to explore its proteome. In depth, iterative optimization allows the identification of novel acrylate‐based compositions with the required chemical, mechanical, and biocompatibility properties allowing proteomic analysis of the extracted ISF for the first time after sampling with swelling MNs. The generated MN arrays show no cytotoxic effect, successfully cross the stratum corneum, and can collect up to 6 µL of dermal ISF in 10 min in vivo. Proteomics lead to the detection of 176 clinically relevant biomarkers in the collected samples validating the use of ISF as a relevant bodily fluid for disease monitoring and diagnostic. Importantly, it is discovered that extraction fingerprint is strongly dependent on the MNs chemistry, and thus specific biomarkers could be selectively extracted by tuning the composition of the patch, making the system versatile and specific.

Owing to their ability to breach the skin in a minimally invasive manner, microneedles (MNs) have seen increased interest for potential diagnostic applications. This is particularly true of polymeric MNs, as the structural and functional properties of the polymer materials used in their fabrication can provide unparalleled advantages and open the door to the diagnostic and monitoring strategies of the future. Polymeric MNs used for diagnostic applications can be broadly divided into swelling MNs for the extraction of dermal interstitial fluid (ISF), surface-functionalized MNs for direct analyte detection, and dissolving MNs for the delivery of diagnostic agents to the skin. In this perspective, we use emblematic examples to highlight the major recent advances in this field and provide commentary and insight into the potential opportunities and remaining challenges faced by each of these MN classes, with a specific focus on the role of materials research in the further development of this field.

The minimally- or non-invasive delivery of therapeutic agents through the skin has several advantages compared to other delivery routes and plays an important role in medical care routines. The development and refinement of new technologies is leading to a drastic expansion of the arsenal of drugs that can benefit from this delivery strategy and is further intensifying its impact in medicine. Within Canada, as well, a few research groups have worked on the development of state-of-the-art transdermal delivery technologies. Within this short review, we aim to provide a critical overview of the development of these technologies in the Canadian environment.