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A microrobot system comprising an untethered tumbling magnetic microrobot, a two-degree-of-freedom rotating permanent magnet, and an ultrasound imaging system has been developed for in vitro and in vivo biomedical applications. The microrobot tumbles end-over-end in a net forward motion due to applied magnetic torque from the rotating magnet. By turning the rotational axis of the magnet, two-dimensional directional control is possible and the microrobot was steered along various trajectories, including a circular path and P-shaped path. The microrobot is capable of moving over the unstructured terrain within a murine colon in in vitro, in situ, and in vivo conditions, as well as a porcine colon in ex vivo conditions. High-frequency ultrasound imaging allows for real-time determination of the microrobot’s position while it is optically occluded by animal tissue. When coated with a fluorescein payload, the microrobot was shown to release the majority of the payload over a 1-h time period in phosphate-buffered saline. Cytotoxicity tests demonstrated that the microrobot’s constituent materials, SU-8 and polydimethylsiloxane (PDMS), did not show a statistically significant difference in toxicity to murine fibroblasts from the negative control, even when the materials were doped with magnetic neodymium microparticles. The microrobot system’s capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.
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Silica-coated gold nanorods with hydrophobic modification show both enhanced two-photon fluorescence and ultrasound drug release
Hydrophobically-modified silica-coated gold nanorods are presented here as multifunctional theranostic agents. A single modification both increases two-photon fluorescence and promotes cavitation-based acoustic signal for imaging. A two-fold greater release of small molecule drugs was observed under ultrasound-mediated conditions as compared to passive release without ultrasound.
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- Award ID(s):
- 2025547
- PAR ID:
- 10444911
- Date Published:
- Journal Name:
- Journal of Materials Chemistry B
- Volume:
- 10
- Issue:
- 47
- ISSN:
- 2050-750X
- Page Range / eLocation ID:
- 9789 to 9793
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D2TB02197H
