Biomimetic Investigation of Intrabolus Pressure Signatures by a Peristaltic Swallowing Robot

Abstract

The relationships among bolus formulation, engineering rheometric quantities, and peristaltic transport effects are examined in this paper. Investigation of a series of synthetic bolus materials and swallowing strategies is conducted using a novel peristaltic swallowing robot inspired by esophageal swallowing, which manifests as a benchtop rheological instrument. To determine the validity of biomimetic swallowing, manometry, a clinical technique for capturing swallowing pressure profiles is used to establish congruence between the robotic findings and those of a clinical nature. To determine the contribution of the bolus and swallowing strategy to the intraluminal pressure signature (ILPS), three parameters were varied: peristaltic wave velocity (20, 30, 40 mm s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ), wavefront length (40, 50, and 60 mm) and starch thickener (Nutulis, Nutricia) concentration (25, 50, 75, 100, and 150 g L <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ) were investigated. Wave velocity and starch-based bolus formulation concentration were found to exhibit the most profound changes in the intrabolus pressure signatures. The highest bolus tail pressure gradient of 0.33 kPa mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> was achieved with a 150 g L <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> bolus formulation being transported at 40 mm s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> with a wavefront length of 60 mm. In each dimension, the relationship between the parameters and features of the manometric pressure signature are found to be nonlinear owing to the shear-thinning, non-Newtonian nature of the model bolus fluid. The robotic ILPSs are synonymous with those of a clinical nature, suggesting that the swallowing robot has merit as a novel, biologically inspired, bolus investigation tool external to the human body.