Magnetic-Acoustic Microbubble Microrobot for Targeted Mechanical Stimulation of Cancer Cells
Cun Wang, Ruicheng Li, Qianyi Dai, Zhaokai Wang, Yongjun Lai, Lidan You, Xian Wang
AI summary
Problem
Magnetic microrobots offer precise control but weak mechanical force, while acoustic microbubbles generate strong forces but lack precise targeting, limiting effective cancer cell disruption.
Approach
The authors fabricated ~10 µm lipid-iron oxide microbubbles via microfluidics and integrated them with a quadrupole magnetic tweezer and 1 MHz ultrasound transducer to enable precise navigation and localized acoustic oscillation.
Key results
- Fabrication of monodisperse ~10 µm MAMs with uniform lipid-IONP shells
- Development of a quadrupole magnetic tweezer achieving 2–3 T/m gradients for precise 3D navigation
- Modeling of nonlinear bubble oscillation predicting >50 kPa shear stress near target cells
- Significant reduction in MDA-MB-231 breast cancer cell viability after targeted MAM stimulation
Why it matters
Provides a clinically translatable, dual-actuation platform for precise mechanical cancer cell disruption and mechanobiology research.
Abstract
Mechanical stimulation has recently been shown as a promising approach to induce targeted cancer cell death. With precise field control, magnetic microrobots were navigated to the tumor site for delivering mechanical stimulation as a new treatment approach. However, most magnetic microrobots suffer from low force output when generating mechanical stimulation. Acoustic microrobots, with a microbubble as their simplest form, generate strong mechanical stimulation yet lack precise position control. In this paper, leveraging the force out- put of the acoustic field and precision of magnetic field control, we present a magnetic acoustic microbubble microrobot (MAM) that integrates magnetic navigation and acoustic stimulation. MAMs were fabricated with DSPC/PEG lipid shells and iron- oxide nanoparticles (IONPs) using a flow-focusing microfluidic method. The size of the fabricated monodispersed MAMs is approximately 10 μm. The fabricated MAMs were navigated by a quadrupole magnetic tweezer system, with a maximum field gradient of 2–3 T/m, and controlled to oscillate to generate mechanical stimulation under an acoustic transducer at 1 MHz. As a proof-of-concept, we applied MAM acoustic treatment to breast cancers (MDA-MB-231) and showed that MAM acoustic treatment led to reduced cell viability compared to the control group and the acoustic-only group. Considering all the components for MAM fabrication are FDA-approved materials, MAM holds promise for clinical translation in tumor mechanical stimulations.