(K-403) Synthesis and Biocompatability of Light Activated Magnetic Microrobots

Friday, October 13, 2023

3:30 PM – 4:30 PM PDT

Location: Exhibit Hall - Row K - Poster # 403

Presenting Author(s)

AM

Amisha Martin

Undergraduate Research Assistant
FAMU-FSU College of Engineering/ National High Magnetic Labratory
Tallahassee, Florida, United States

Co-Author(s)

Astrid Daugherty (she/her/hers)

Research Associate
FAMU-FSU College of Engineering
Tallahassee, Florida, United States
MA

Makena Andersen

Research Associate
Lewis & Clark College, Department of Chemistry & Physics
Tallahassee, Florida, United States
Izabela Kowalik, UG

Research Associate
National High Magnetic Field Lab
Land O' Lakes, Florida, United States
NK

Navneet Kaur

Postdoctoral Research
FAMU-FSU College of Engineering, United States
MS

Mary Jean Savitsky

PhD Student
FAMU-FSU College of Engineering, United States

Primary Investigator(s)

JA

Jamel Ali

Professor
FAMU-FSU College of Engineering, Florida, United States

Introduction::

Photocatalyst, composed of biodegradable semiconductor materials, has shown promise for use in biomedical applications such as cancer theranostics and antibiotic resistant biofilm treatment. Active wireless guidance of light-powered photocatalyst could serve to greatly improve the effectiveness of photocatalyst-based therapeutics. Hematite (α-Fe2O3) microparticles, a weakly canted-antiferromagnetic iron oxide with a stable crystalline phase, is a suitable photocatalyst as it can convert environmental peroxide, found in the body, into hydroxyl radicals in the presence of UV light that can effectively treat diseased tissue and foreign pathogens. Hematite also possesses magnetic properties, is biocompatible, and can naturally degrade in acidic biological environments. Here we synthesize hematite micromotors with three distinct morphologies and evaluate their magnetic attributes, biocompatability, and light activated motility.

Materials and Methods::

Using a sol-gel technique, hematite particles were synthesized with three morphologies: pseudo-cubic, rod-shaped, and ellipsoidal. For pseudo-cubic particles, a solution of iron (III) chloride was mixed with a concentrated solution of sodium hydroxide. To produce ellipsoidal and rod-shaped particles, various amounts of sodium sulfate (Na2SO4) were added to FeCl3 and NaOH solutions, respectively. After dissolving the solutions and incubating for eight days at 100°C, micrometer sized particles were formed. Synthesized particles were copiously washed with deionized water followed by centrifugation at 3,000 x g for ten minutes. The morphology and elemental composition of the particles was characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). X-ray Diffraction (XRD) was employed to study the crystal structure, and the magnetic capabilities were measured using a Super-Conducting Quantum Interference Device (SQUID). Motility was tested and recorded with and without UV irradiation using ImageJ (NIH). Additionally, the biocompatability of particles was evaluated with a mouse fibroblast cell line, NIH3T3 (ATCC), using MTT assays.

Results, Conclusions, and Discussions::

Scanning electron microscopy (SEM) data was used for characterization of the size and shape of the hematite particles. The pseudo-cubic particles had an average length of ~1.2µm, the ellipsoid particles had an average diameter of ~1.1µm, and the rod-shaped particles had an average aspect ratio of 5:11. Biocompatability tests were performed on a NIH3T3 fibroblast cell line. Particles with different shapes were incubated with cells at a concentration of 100µg/mL for 24h. It was observed that ~80% cell viability was achieved for all particle morphologies, indicating the biocompatability of the magnetic microparticles.

Figure 1: SEM micrographs of synthesized hematite microparticles: (A) Pseudo-cubic, (B) Rods-shaped, (C) Ellipsoidal. (scale bar is10µm) (D) MTT biocompatability assay. 

Conclusion: Therapeutic photocatalysis using hematite, a stable iron oxide, shows promise for cancer and antibiotic biofilm treatment with UV light. Monodispersed micrometer scale hematite particles were successfully synthesized and characterized for structural and compositional properties. At concentrations at and below 100µg/mL, all particles displayed high biocompatibility when compared to control samples. Future and current experiments are on-going, aimed at investigating magnetic control and therapeutic delivery both in vitro and in vivo.

Acknowledgements (Optional): :

This work was funded by the National Science Foundation (No. EES-2000202, EES- 2219558) and supported by the NSF FAMU CREST Center award (No. EES-1735968), and Dow. This research work was also supported by The Grainger Foundation Frontiers of Engineering Grant under the National Academy of Sciences Award Number: 2000013181. This material is based upon work supported by the Air Force Office of Scientific Research under award number FA9550-22-1-0247. All the work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida.

The content is solely the responsibility of the authors and does not necessarily represent the official views of The Grainger Foundation or the National Academy of Sciences.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the United States Air Force.

References (Optional): :