Conformal Cytocompatible Ferrite Coatings Facilitate the Realization of a Nanovoyager in Human Blood

Abstract

Controlled motion of artificial nanomotors in biological environments, such as blood, can lead to fascinating biomedical applications, ranging from targeted drug delivery to microsurgery and many more. In spite of the various strategies used in fabricating and actuating nanomotors, practical issues related to fuel requirement, corrosion, and liquid viscosity have limited the motion of nanomotors to model systems such as water, serum, or biofluids diluted with toxic chemical fuels, such as hydrogen peroxide. As we demonstrate here, integrating conformal ferrite coatings with magnetic nanohelices offer a promising combination of functionalities for having controlled motion in practical biological fluids, such as chemical stability, cytocompatibility, and the generated thrust. These coatings were found to be stable in various biofluids, including human blood, even after overnight incubation, and did not have significant influence on the propulsion efficiency of the magnetically driven nanohelices, thereby facilitating the first successful "voyage" of artificial nanomotors in human blood. The motion of the "nanovoyager" was found to show interesting stick-slip dynamics, an effect originating in the colloidal jamming of blood cells in the plasma. The system of magnetic "nanovoyagers" was found to be cytocompatible with C2C12 mouse myoblast cells, as confirmed using MTT assay and fluorescence microscopy observations of cell morphology. Taken together, the results presented in this work establish the suitability of the "nanovoyager" with conformal ferrite coatings toward biomedical applications.

Fabrication of Micro/Nanoscale Motors

“…By integration of a conformal ferrite coating, Venugopalan et al reported a cytocompatible magnetically driven helical micromotor that can be propelled in human blood at negligible dilutions. 237 Furthermore, Nelson and co-workers have designed a platform for the biomedical application of magnetically driven motors in the eye. 238 The possibility of targeted retinal drug delivery, 239 retinal vein cannulation, and oxygen sensing 240 with the use of magnetic microrobots has been demonstrated.…”

3D-Printed Biodegradable Microswimmer for Drug Delivery and Targeted Cell Labeling

“…http://dx.doi.org/10.1101/379024 doi: bioRxiv preprint first posted online Jul. 28, 2018; rotation of bacterial flagella, and the beating of paramecium cilia, which have so far inspired many synthetic swimmer designs (26)(27)(28)(29)(30)(31). Inspired by a similar mechanism, the design of our microrobotic swimmer is illustrated in Fig.…”

Magnetic Nanoferrites for RF CMOS: Enabling 5G and Beyond

“…42 Such a high degree of crystallographic inversion can alter the crystal symmetry as well as the spin structure, and may thereby induce a higher anisotropy and an enhanced f FMR as a consequence. Although it is in its infancy, this approach can be an excellent way to modulate ferromagnetic resonance frequency of spinel ferrites via the soft-chemical route.…”