27 Citations (SciVal)

Abstract

Conductive polymeric microneedle (MN) arrays as biointerface materials show promise for the minimally invasive monitoring of analytes in biodevices and wearables. There is increasing interest in microneedles as electrodes for biosensing, but efforts have been limited to metallic substrates, which lack biological stability and are associated with high manufacturing costs and laborious fabrication methods, which create translational barriers. In this work, additive manufacturing, which provides the user with design flexibility and upscale manufacturing, is employed to fabricate acrylic-based microneedle devices. These microneedle devices are used as platforms to produce intrinsically-conductive, polymer-based surfaces based on polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). These entirely polymer-based solid microneedle arrays act as dry conductive electrodes while omitting the requirement of a metallic seed layer. Two distinct coating methods of 3D-printed solid microneedles, in situ polymerization and drop casting, enable conductive functionality. The microneedle arrays penetrate ex vivo porcine skin grafts without compromising conductivity or microneedle morphology and demonstrate coating durability over multiple penetration cycles. The non-cytotoxic nature of the conductive microneedles is evaluated using human fibroblast cells. The proposed fabrication strategy offers a compelling approach to manufacturing polymer-based conductive microneedle surfaces that can be further exploited as platforms for biosensing.

Original languageEnglish
Article number2206301
JournalSmall
Volume19
Issue number14
Early online date3 Jan 2023
DOIs
Publication statusPublished - 5 Apr 2023

Bibliographical note

Funding Information:
A.K., Y.L.M., and J.G.T. contributed equally to this work. This research was financially supported by the Engineering and Physical Sciences Research Council Grant EP/V010859/1 and the Royal Society Research Grant RSG\R1\201185. The authors would like to thank Lina Wang and Victor Li for their assistance with the CV and sample preparation inductions. The authors recognize the Material and Chemical Characterisation Facility (MC) at the University of Bath (doi.org/10.15125/mx6j‐3r54) and Dr. Philip Fletcher's electron microscopy expertise and assistance. Last, the authors would like to thank the Department of Chemistry at the University of Bath for allowing us to use some of the analytical equipment in their facilities. The authors thank Professor Richard Guy for his expertise and donation of porcine skin during experimentation. The authors acknowledge the Micro‐Mechanical Facility, in the Faculty of Engineering, University of Bath. The authors thank the editor and reviewers for their constructive comments which improved the manuscript. 2

Keywords

  • PEDOT:PSS
  • biocompatible
  • biosensors
  • conductive microneedles
  • polypyrrole
  • stereolithography 3D printing

ASJC Scopus subject areas

  • Biotechnology
  • Chemistry(all)
  • Biomaterials
  • Materials Science(all)

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