21 accepted papers
In the design of microrobots, a helical geometry is pivotal to overcome the time-reversal constraints of the scallop theorem. The helical geometry enables the microrobots to propel themselves forward in viscous fluids with a corkscrew like motion when they are allowed to rotate. It is physically adv
Until now, the potential of untethered magnetic robots (UMRs), propelled by external time-periodic magnetic fields, has been hindered by the limitations of wireless manipulation systems or noninvasive imaging techniques combined. The need for simultaneous actuation and noninvasive localization impos…
This paper explores the application of X-ray-guided magnetic fields for the wireless control of untethered magnetic robots (UMRs) within cerebral vascular phantoms. With a focus on addressing challenges associated with strokes and brain aneurysms, the study aims to enhance neurosurgical procedures b…
One approach to the wireless actuation and gravity compensation of untethered helical magnetic devices (UHMD) is through swimming with a non-zero angle of attack (AoA). This configuration allows us to counteract gravity, so that for a given desired path, we can move the UHMD controllably without dri…
Magnetic nanoparticles can be electrostatically assembled around sperm cells to form biohybrid micro robots. These biohybrid microrobots possess sufficient magnetic material to potentially allow for pulse-echo localization and wireless actuation. Alternatively, magnetic excitation of these nanoparti…
To date, all previous research in the wireless magnetic actuation of untethered helical devices has achieved motion stability using feedback control in vitro. However, feedback control systems are likely to be affected by the increased sensory uncertainty during in vivo trials. In this study we inve…
Magnetic actuation of minimally invasive medical tetherless devices holds great promise in several biomedical applications. However, there are still several challenges in noninvasive localization, both in terms of sensing detectable signals of these devices and estimating their states. In this work,
Control of tetherless magnetically actuated helical robots using rotating dipole fields has a wide variety of medical applications. The most promising technique in manipulation of these robots involves a rotating permanent magnet controlled by a robotic manipulator. In this work, we study the open-l…
Magnetically-driven screws operating in soft-tissue environments could be used to deploy localized therapy or achieve minimally invasive interventions. In this work, we characterize the closed-loop behavior of magnetic screws in an agar gel tissue phantom using a permanent magnet-based robotic syste…
A soft two-tailed microrobot in low Reynolds number fluids does not achieve forward locomotion by identical tails regardless to its wiggling frequency. If the tails are nonidentical, zero forward locomotion is also observed at specific oscillation frequencies (which we refer to as the reversal frequ
A simple way to mitigate the potential negative side-effects associated with chemical lysis of a blood clot is to tear its fibrin network via mechanical rubbing using a helical robot. Here, we achieve mechanical rubbing of blood clots under ultrasound guidance and using external magnetic actuation.
Mid-Air haptic devices have become an active area of research because of their potential impact to augmented/virtual reality. In this work, we develop an electromagnetic-based haptic interface to provide controlled magnetic forces on a wearable orthopedic finger splint with a single magnetic dipole.
Magnetotactic bacteria have the potential to controllably reach stagnant fluids inside the human body and achieve targeted drug delivery. In this application, motion of the magnetotactic bacteria is influenced by the near-surface effects such as the background flows and surface interactions. Here, w…
In this study, we develop an electromagnetic-based haptic interface to provide controlled magnetic forces to the operator through a wearable haptic device (an orthopedic finger splint with single dipole moment) without position feedback. First, we model the electromagnetic forces exerted on a single…
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 hydrod
In travelling towards the oviducts, sperm cells undergo transitions between planar to helical flagellar propulsion by a beating tail based on the viscosity of the environment. In this work, we aim to model and mimic this behaviour in low Reynolds number fluids using externally actuated soft robotic…
Magnetotactic bacteria have the potential to controllably reach deep-seated regions of the body via vessels and achieve targeted drug delivery. In this application, motion of the magnetotactic bacteria is influenced by the strength of the external magnetic field. Here, we investigate the swimming ch
We use electrospinning to fabricate sperm-shaped magnetic microrobots with a range of diameters from 50 μm to 500 μm. The variables of the electrospinning operation (voltage, concentration of the solution, dynamic viscosity, and distance between the syringe needle and collector) to achieve beading e
In contact micromanipulation, the adhesive forces between manipulators and microobjects decrease the chances of achieving successful releases at the desired positions. We study a non-contact micromanipulation technique of microbeads (300 µm in average diameter) using clusters of paramagnetic micropa…
In targeted therapy, clusters of drug carriers (nanoparticles and microparticles) could be in contact with a surface such as the lumen of blood vessels and the interior of the gastrointestinal tract. We study the motion characteristics of clusters of microparticles when they slide on a surface under…
We control the motion of helical microrobots with average diameter of 500 µm in two-dimensional (2D) and three-dimensional (3D) spaces using two synchronized rotating dipole fields. The utilization of the two synchronized dipole fields not only increases the magnetic torque exerted on the magnetic d…