Functionalized microneedles for continuous glucose monitoring

Abstract

Microneedles (MNs) have been established as promising medical devices as they are minimally invasive, cause less pain, and can be utilized for self-administration of drugs by patients. There has been rapid development in MNs for transdermal monitoring and diagnostic systems, following the active research on fabrication methods and applications for drug delivery. In this paper, recent investigations on bio-sensing using MNs are reviewed in terms of the applicability to continuous glucose monitoring system (CGMS), which is one of the main research focuses of medical engineering technologies. The trend of the functionalized MNs can be categorized as follows: (i) as a sensing probe, and (ii) as a biological fluid collector. MNs as in vivo sensors are mainly integrated or coated with conductive materials to have the function as electrodes. MNs as fluid collectors are given a certain geometrical design, such as a hollow and porous structure aided by a capillary action or negative pressure, to extract the interstitial fluids or blood for ex vivo analysis. For realization of CGMS with MNs, a long-term accurate measurement by the MN-based sensing probe or a fluidic connection between the MN-based fluid collector and the existing microfluidic measurement systems should be investigated.

Hydrogel‐Forming Microneedles: Current Advancements and Future Trends

“…It is not known whether the concentration of biomarkers in ISF compared to blood plasma is consistently high enough and an accurate representation for analysis, but reports claim ISF is fairly representative of true biomarker concentrations. This finding indicates that ISF is a potential alternative for some (but currently not all) biomarkers, such as glucose, [ 80 ] for monitoring, compared to the use of blood plasma, which can be invasive to extract. Samant and Prausnitz [ 13 ] used crosslinked PVA HFMs to extract ISF, showing that the use of HFMs is more effective than other methods, such as hollow MNs and osmotically driven flow for ISF extraction.…”

Engineering Microneedles for Therapy and Diagnosis: A Survey

“…Clinically ideal MNs with good biocompatibility, strong mechanical strength, and cargos (such as proteins, peptides and vaccines) are highly desirable to achieve sensing or drug release in the skin. By rational design (including shape, aspect ratio, tip radius and length, and base width), MNs with excellent physical, chemical, and biological properties have been fabricated and utilized for applications of transdermal sensing, extraction of biofluids for diagnostics, and transdermal delivery [27,29,31].…”

“…Many reviews on microneedle technology have been published in recent years. However, many of them typically focus on a specific aspect, such as materials science and manufacture [26], glucose monitoring [27], polymeric MNs' application [14], diagnostics [28,29], and drug delivery [30,31]. The systematical review, which elaborates on the basic knowledge and main points of MNs, and covers the latest application of diagnosis and therapy, is still in its infancy [32].…”

Correction to: Functionalized microneedles for continuous glucose monitoring

“…After publication of this article [1], the author noticed there are some conversion errors with the below characters and units in the article body text. The corrections are detailed below:‘pTAS’ should be ‘µTAS’‘pm’ should be ‘µm’…”