Conductive Polymer‐Coated 3D Printed Microneedles: Biocompatible Platforms for Minimally Invasive Biosensing Interfaces. Issue 14 (3rd January 2023)

• Record Type: Journal Article
• Authors: Keirouz, Antonios; Mustafa, Yasemin L.; Turner, Joseph G.; Lay, Emily; Jungwirth, Ute; Marken, Frank; Leese, Hannah S.
• Is Part Of: Small. Volume 19:Issue 14(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-03
• Subjects: biocompatible -- biosensors -- conductive microneedles -- PEDOT:PSS -- polypyrrole -- stereolithography 3D printing; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202206301
• Languages: English
• ISSNs: 1613-6810

Abstract

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. Abstract : The presented work provides a straightforward novel approach to developing 3D stereolithography printed microneedle arrays with a 360° conductive overlay entirely made of intrinsically conductive polymers (ICPs). By omitting the requirement for a metallic seed layer, the described methodology produces conductive, biocompatible, and mechanically stable microneedle platforms capable of acting as an interface surface for biosensing.