By combining my research experience in FUS and electromagnetism, I have defined a collaborative project between the AI for manufacturing lab and Maglev Microrobotics Laboratory to develop new technology for FUS therapy using magnetomotive techniques. 

One promising strategy to mediate FUS and improve therapeutic results at low ultrasonic powers is to use magnetic nanoparticles (MNPs) as FUS-enhancing agents. MNPs have been accepted as contrast and therapeutic agents and have been utilized in medical imaging studies. Once delivered to the target site, MNPs can enhance FUS’s thermal effects by elevating the absorption rate of ultrasonic energy by the target medium. During my PhD studies, I conducted a comprehensive study on the effects of various nanoparticle (NP)-based agents for the FUS treatment. I also derived the governing equations for MNP-mediated FUS and examined the feature effects of MNPs on FUS’s therapeutic parameters. However, the efficient application of MNPs during the FUS treatment requires high volume concentrations of MNPs at the target area while the controlled delivery of nanoscale agents to the tumor site deep inside the body is extremely difficult [6]. Therefore, there is a great need for the development of new methods and systems for MNP-mediated FUS therapy to (i) increase the controlled delivery of MNPs to the target area, and (ii) improve the efficacy of MNPs during the FUS heating procedures.

This research project aims to develop a multi-functional system for MNP-mediated FUS therapy using the magnetomotive technique. Here, a magnetomotive system has been designed and integrated with a FUS therapeutic system to (i) enhance the controlled delivery of MNPs to the target area, and (ii) to improve the efficacy of MNPs during FUS therapy, thereby enhancing the heating mechanism of MNP-mediated FUS treatment. The controlled delivery of MNPs to the region of interest can be accomplished by the accurate control of the features of the magnetic field, generated by the system. In addition, the magnetomotive system can directly enhance the efficacy of MNPs during the FUS heating procedures through two major mechanisms. First, it can increase the temperature of MNPs due to the magnetic hyperthermia effect while a medium containing MNPs with higher temperatures can absorb higher amounts of acoustic energy because of the heat conduction process. In another mechanism, the magnetomotive force generated by the system can increase the relative movement of MNPs with respect to the surrounding biological medium during FUS. This can also result in the higher absorption of ultrasonic energy by the target medium due to the viscous wave effect. 

A schematic of the proposed technique is shown below:

First, a novel magnetomotive system has been designed, optimized, and fabricated for stimulating and guiding MNPs. The features of the system, including the numbers, the size, and the orientation of coils with respect to each other, have been determined using the results from the computational simulations and optimization studies. The required signal to drive each coil at a desired frequency and power can be produced by a function generator and a current amplifier. Here, the control of the system can also be achieved by training a supervisory control algorithm using computational simulations.

The magnetomotive setup, designed and developed by the maglev team supervised by Prof. Behrad Khamesee, for the current project is shown below

An experimental study has been conducted for monitoring the potential effects of the magnetomotive system to enhance (i) the controlled delivery of MNPs, and (ii) the efficacy of MNPs during the FUS heating procedures. Tissue phantoms with similar porous structures and thermo-acoustic properties to biological tissue have been developed for hosting MNPs. First, the influence of the magnetomotive system on the controlled delivery of MNPs to the focal area has been investigated. Here, the aim is to control the features of the magnetic field, including the direction and strength for each coil, and the phase difference between them to maximize the accumulation of nanoparticles at the focal area. At the next step, the designed magnetomotive system has been integrated with a FUS system to examine the influence of the magnetomotive system on the performance of MNPs during FUS. To this end, the temperature profile during the FUS procedures on tissue phantoms with various concentrations of MNPs is monitored and compared with the results when the magnetomotive effects are applied. In addition, a parametric study is performed, revealing the effects of magnetomotive parameters (i.e., frequency, strength, and gradient of the magnetic field) on the performance of MNPs during the FUS heating procedure.

The experimental setup on Magnetic Field-Assisted FUS using tissue-mimicking phantoms.