Additive manufacturing of high-resolution solid microneedles via continuously variable stacked extrusion (CVSE) of conductive thermoplastic using a fused filament fabrication (FFF) printer

Abstract

This study introduces Continuously Variable Stacked Extrusion (CVSE), a novel method for fabricating high-resolution microneedles using standard Fused Filament Fabrication (FFF) hardware. Unlike traditional FFF approaches requiring chemical etching, CVSE combines printing and drawing techniques through continuous vertical movement to create smooth, precise microneedles. Using conductive PLA filament, we demonstrated uniform arrays of microneedles with tip diameters under 25 μm and heights of 1185 ± 28 μm. The method showed excellent repeatability and enabled various needle profiles, including barbed and tissue-interlocking designs. This approach represents a significant advancement in microneedle fabrication using widely available FFF equipment.