Helical Robot Research Articles

Rubbing Against Blood Clots Using Helical Robots: Modeling and In Vitro Experimental Validation

The risk of side effects from thrombolytic agents can be minimized by using smaller doses, assisted by mechanical rubbing against blood clots using helical robots. Quantifying this observation, we study the influence of rubbing against clots on their removal rate in vitro. First, we present a hydrodynamic model of the helical robot based on the resistive-force theory to investigate the rubbing behavior of the clots using robot driven by two rotating dipole fields. Second, we experimentally evaluate the influence of the rubbing on the removal rate of the blood clots. Not only do we find that the removal rate of mechanical rubbing (-0.56 ± 0.27 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /min) is approximately three times greater than the dissolution rate of chemical lysis using streptokinase (-0.17 ± 0.032 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /min), but we also show that this removal rate can be controlled via the rubbing speed of the robot.

Effects of poiseuille flows on swimming of magnetic helical robots in circular channels

This study reports experimental and numerical model results on swimming of microswimmers inside circular channels. Designed to mimic the swimming behavior of biological organisms at low Reynolds number flows, a number of microswimmers are manufactured utilizing a 3D printer and consist of a helical tail and a body that encapsulates a small magnet. The swimming motion results from the synchronized rotation of the artificial swimmer with the rotating magnetic field induced by three electromagnetic-coil pairs. In order to obtain linear and angular velocities and to analyze the motion of the microswimmer, a computational model is developed to obtain swimmer velocities from the solutions of three-dimensional steady Stokes equations which govern the flow around the swimmers inside the channel. Experiments and numerical simulations are carried out for a number of configurations with different geometric parameters and flow rates in the channel filled with glycerol. Numerical results agree well with experimentally measured average velocities of swimmers. Results describe the influence of the flow rate, length of the tail, diameter of the channel, and the direction of the rotation of the swimmer on the velocity and trajectories of microswimmers.

Dual-body magnetic helical robot for drilling and cargo delivery in human blood vessels

We propose a novel dual-body magnetic helical robot (DMHR) manipulated by a magnetic navigation system. The proposed DMHR can generate helical motions to navigate in human blood vessels and to drill blood clots by an external rotating magnetic field. It can also generate release motions which are relative rotational motions between dual-bodies to release the carrying cargos to a target region by controlling the magnitude of an external magnetic field. Constraint equations were derived to selectively manipulate helical and release motions by controlling external magnetic fields. The DMHR was prototyped and various experiments were conducted to demonstrate its motions and verify its manipulation methods.