Soft tissue traversal with zero net force: Feasibility study of a biologically inspired design based on reciprocal motion

Abstract

This paper builds on previous work on the biologically inspired microtexturing of next-generation neurosurgical probes [3]. It reports on the outcome of a feasibility study, where a biomimetic robotic actuator was used to demonstrate effective soft tissue traversal (i.e. motion along the surface of a soft tissue) through the reciprocating motion of custombuilt anisotropic surface textures, without the need to apply an external force to push the tissue along the surface and while causing minimum tissue damage. The protocol applied to characterize the interaction between the samples and the different tissues was considered, including parameters such as texture size and geometry, normal load, frictional forces and reciprocating speed and acceleration. A number of microtextured samples, with features including every combination of two teeth geometries (triangular and fin-like) and three tooth sizes (500µm, 100µm and 50µm tooth height), were manufactured and mounted onto a custom-built reciprocating mechanism. First, a variety of soft tissue specimens was tested to qualify the sample/tissue interaction behavior. Subsequently, a comparative study on agarose gel and gelatin was performed to investigate the motion characteristics and resulting tissue damage on brainlike material and to explore what conditions are needed to achieve forward motion.