Tapered Magnetic Soft Continuum Catheters with Integrated Microchannels for Cerebral Intra-Arterial Chemotherapy Delivery

Abstract

Magnetic soft continuum robots (MSCRs) offer the possibility for wireless manipulation, compliant shape-forming, and miniaturization to the milli- and submillimeter scales. This presents them as an attractive choice in the development of robotic guidewires and catheters for endovascular applications. However, few approaches have considered strategies for geometric modification to enhance navigation and therapeutic delivery. These aspects are of high relevance for applications such as intra-arterial chemotherapeutic delivery. Here, we present an octopus tentacle-inspired MSCR with a monolithic material composition, tapered geometry of ≤ 2 mm, and integrated microchannels. We consider the suitability of a discrete elastic modeling approach alongside finite element based and material point method (MPM) simulations for capturing the deflection behavior of the tapered design under magnetic actuation. The MPM demonstrates the greatest accuracy, with root mean square errors in tip angle between 2.74° and 5.28°. For higher taper designs, experimental results highlight improved deflection under low magnetic field strengths (<5 mT) and an improved workspace at high actuation angles (up to 320°). We subsequently utilize tapered designs with a 0.66 mm distal tip diameter and embedded axial and lateral microchannel networks for localized drug simulant delivery in a neurovascular tumor phantom. We demonstrate significant improvements in localized drug delivery along specific vascular pathways in comparison to systemic intra-arterial delivery.