Polymer-Based Microneedles for Decentralized Diagnostics and Monitoring: Concepts, Potentials, and Challenges

Abstract

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.

Mapping the Mechanical and Immunological Profiles of Polymeric Microneedles to Enable Vaccine and Immunotherapy Applications

“…For the reasons just mentioned, translating MNs from bench to clinic also requires attention to fabrication processes. We used a solvent casting method for fabricating the MNs ( 39 – 41 ), which is more reproducible and robust compared to other techniques like microlithography and laser ablation ( 42 ). The manufacturing technique can also impact the mechanical properties, including key parameters, such as fracture force and stiffness: with insufficient fracture force values, MNs could fracture during insertion; with inappropriate levels of stiffness/flexibility the MN patch application, adhesion, and durability may be mismatched with the intended application ( 43 , 44 ).…”

Biomaterials Technology for AgroFood Resilience

“…In addition, polymeric microneedles have attracted considerable attention as potential diagnostic devices for biomedical applications due to their ability to extract dermal interstitial fluids with minimal invasion. [ 394 ] Sampling target fluids from tissues and transporting them to reporting devices are the critical performances required for these microneedles. Therefore, to develop new biomaterials, understanding fluid transport mechanisms, such as diffusion, capillary action, osmosis, and pressure‐driven convection, and their manipulation in the microneedle devices are required.…”

The Future of Healthcare Materials

“…Gwinn and Copp et al have recently utilized machine learning to design DNA stabilized silver clusters . Programmable hydrogels have also been reported to improve the cargo loading and overall performance of the polymeric platforms, which is crucial for injectable biomaterials. , Brambilla et al also showed that polymer-based microneedles can be successfully used for individualized diagnostic and monitoring . Further, promising reports toward individualized therapy, however, pertain to using specialized nucleic acids and antibodies as cargo, such as the work of Li et al, Chung et al, and Caruso et al…”

“…14,15 Brambilla et al also showed that polymer-based microneedles can be successfully used for individualized diagnostic and monitoring. 16 Further, promising reports toward individualized therapy, however, pertain to using specialized nucleic acids and antibodies as cargo, such as the work of Li et al, 17 Chung et al, 18 and Caruso et al 19 It is clear that the road to the "perfect" delivery platform, if that ever exists, is not easy or in this sense straightforward, but we are learning valuable information along the way. This has already made the rapid production of vaccines for SARS-Cov-2 possible, and the next frontier is personalized targeted therapy.…”