Print Email Facebook Twitter Experimental evaluation of a self-propelling bio-inspired needle in single- and multi-layered phantoms Title Experimental evaluation of a self-propelling bio-inspired needle in single- and multi-layered phantoms Author Scali, M. (TU Delft Medical Instruments & Bio-Inspired Technology) Breedveld, P. (TU Delft Medical Instruments & Bio-Inspired Technology) Dodou, D. (TU Delft Medical Instruments & Bio-Inspired Technology) Date 2019 Abstract In percutaneous interventions, reaching targets located deep inside the body with minimal tissue damage and patient pain requires the use of long and thin needles. However, when pushed through a solid substrate, a structure with a high aspect ratio is prone to buckle. We developed a series of multi-element needles with a diameter smaller than 1 mm and a length larger than 200 mm, and we experimentally evaluated the performance of a bio-inspired insertion mechanism that prevents needle buckling of such slender structures. The needles consisted of Nitinol wires and advance into a substrate by pushing the wires forward one after the other, followed by pulling all the wires simultaneously backward. The resulting net push force is low, allowing the needles to self-propel through the substrate. We investigated the effect of the needle design parameters (number of wires and their diameter) and substrate characteristics (stiffness and number of layers) on the needle motion. Three needle prototypes (consisting of six 0.25-mm wires, six 0.125-mm wires, and three 0.25-mm wires, respectively) were inserted into single- and multi-layered tissue-mimicking phantoms. The prototypes were able to move forward in all phantoms without buckling. The amount of needle slip with respect to the phantom was used to assess the performance of the prototypes. The six-wire 0.25-mm prototype exhibited the least slip among the three prototypes. Summarizing, we showed that a bio-inspired motion mechanism prevents buckling in very thin (diameter <1 mm), long (length >200 mm) needles, allowing deep insertion into tissue-mimicking phantoms. To reference this document use: http://resolver.tudelft.nl/uuid:f4d85526-4806-4907-8732-811df3b23c1c DOI https://doi.org/10.1038/s41598-019-56403-0 ISSN 2045-2322 Source Scientific Reports, 9 (1) Part of collection Institutional Repository Document type journal article Rights © 2019 M. Scali, P. Breedveld, D. Dodou Files PDF s41598_019_56403_0.pdf 2.64 MB Close viewer /islandora/object/uuid:f4d85526-4806-4907-8732-811df3b23c1c/datastream/OBJ/view