10
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Functionalized microneedles for continuous glucose monitoring

      review-article
      ,
      Nano Convergence
      Springer Singapore
      Microneedles, Glucose sensor, Interstitial fluids

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          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.

          Related collections

          Most cited references114

          • Record: found
          • Abstract: found
          • Article: not found

          Microneedles for transdermal drug delivery.

          The success of transdermal drug delivery has been severely limited by the inability of most drugs to enter the skin at therapeutically useful rates. Recently, the use of micron-scale needles in increasing skin permeability has been proposed and shown to dramatically increase transdermal delivery, especially for macromolecules. Using the tools of the microelectronics industry, microneedles have been fabricated with a range of sizes, shapes and materials. Most drug delivery studies have emphasized solid microneedles, which have been shown to increase skin permeability to a broad range of molecules and nanoparticles in vitro. In vivo studies have demonstrated delivery of oligonucleotides, reduction of blood glucose level by insulin, and induction of immune responses from protein and DNA vaccines. For these studies, needle arrays have been used to pierce holes into skin to increase transport by diffusion or iontophoresis or as drug carriers that release drug into the skin from a microneedle surface coating. Hollow microneedles have also been developed and shown to microinject insulin to diabetic rats. To address practical applications of microneedles, the ratio of microneedle fracture force to skin insertion force (i.e. margin of safety) was found to be optimal for needles with small tip radius and large wall thickness. Microneedles inserted into the skin of human subjects were reported as painless. Together, these results suggest that microneedles represent a promising technology to deliver therapeutic compounds into the skin for a range of possible applications.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Biodegradable polymer microneedles: fabrication, mechanics and transdermal drug delivery.

            To overcome the skin's barrier properties that block transdermal delivery of most drugs, arrays of microscopic needles have been microfabricated primarily out of silicon or metal. This study addresses microneedles made of biocompatible and biodegradable polymers, which are expected to improve safety and manufacturability. To make biodegradable polymer microneedles with sharp tips, micro-electromechanical masking and etching were adapted to produce beveled- and chisel-tip microneedles and a new fabrication method was developed to produce tapered-cone microneedles using an in situ lens-based lithographic approach. To replicate microfabricated master structures, PDMS micromolds were generated and a novel vacuum-based method was developed to fill the molds with polylactic acid, polyglycolic acid, and their co-polymers. Mechanical testing of the resulting needles measured the force at which needles broke during axial loading and found that this failure force increased with Young's modulus of the material and needle base diameter and decreased with needle length. Failure forces were generally much larger than the forces needed to insert microneedles into skin, indicating that biodegradable polymers can have satisfactory mechanical properties for microneedles. Finally, arrays of polymer microneedles were shown to increase permeability of human cadaver skin to a low-molecular weight tracer, calcein, and a macromolecular protein, bovine serum albumin, by up to three orders of magnitude. Altogether, these results indicate that biodegradable polymer microneedles can be fabricated with an appropriate geometry and sufficient strength to insert into skin, and thereby dramatically increase transdermal transport of molecules.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Microneedle technologies for (trans)dermal drug and vaccine delivery.

              Microneedles have been used for the dermal and transdermal delivery of a broad range of drugs, such as small molecular weight drugs, oligonucleotides, DNA, peptides, proteins and inactivated viruses. However, until now there are no microneedle-based (trans)dermal drug delivery systems on the market. In the past decade various types of microneedles have been developed by a number of production processes. Numerous geometries of microneedles have been designed from various materials. These microneedles have been used for different approaches of microneedle-based (trans)dermal drug delivery. Following a brief introduction about dermal and transdermal drug delivery, this review describes different production methods for solid and hollow microneedles as well as conditions that influence skin penetration. Besides, the four microneedle-based (trans)dermal drug delivery approaches are discussed: "poke and flow", "poke and patch", "poke and release", and "coat and poke". A separate section of this review is devoted to the use of microneedles for the delivery of therapeutic proteins and vaccines. Finally, we give our view on research and development that is needed to render microneedle-based (trans)dermal drug delivery technologies clinically useful in the near future. Copyright © 2012 Elsevier B.V. All rights reserved.
                Bookmark

                Author and article information

                Contributors
                takekai@iis.u-tokyo.ac.jp
                bjoonkim@iis.u-tokyo.ac.jp
                Journal
                Nano Converg
                Nano Converg
                Nano Convergence
                Springer Singapore (Singapore )
                2196-5404
                24 October 2018
                24 October 2018
                December 2018
                : 5
                Affiliations
                ISNI 0000 0001 2151 536X, GRID grid.26999.3d, Institute of Industrial Science, , The University of Tokyo, ; 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505 Japan
                Article
                161
                10.1186/s40580-018-0161-2
                6199201
                096d096d-24d8-4777-98b4-8889be452f95
                © The Author(s) 2018

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

                Categories
                Review
                Custom metadata
                © The Author(s) 2018

                microneedles,glucose sensor,interstitial fluids
                microneedles, glucose sensor, interstitial fluids

                Comments

                Comment on this article