Document Type

Article

Publication Date

4-7-2026

Publication Source

ACS Applied Nano Materials

Abstract

Magnetic cellulose nanocrystal (MCNC) nanocomposites are promising sustainable and biocompatible platforms for magnetic hyperthermia; however, the molecular mechanisms governing Fe3O4 adsorption and deposition onto CNCs remain poorly understood. Here, sulfated (S-CNC) and TEMPO-oxidized CNCs (T-CNC) were used to prepare nanocomposites at 1:2 and 1:4 CNC:Fe3O4 mass ratios, enabling a systematic evaluation of how surface chemistry and nanoparticle loading dictate interfacial interactions and magneto-colloidal behavior. Bare magnetite nanoparticles were 21 ± 5 nm by TEM but grew to 144 ± 18 in the DLS measurement at pH 7. The S-CNC nanocomposites had hydrodynamic sizes between 144 and 210 nm, not much larger than the 140 nm long CNC rods, suggesting an enhanced dispersion stability compared to Fe3O4alone. X-ray photoelectron spectroscopy combined with density functional theory revealed that −OH and −COOH groups drive electrostatic adsorption with charge transfer from Fe3O4 to the CNC surface, while T-CNCs showed more favorable adsorption energies and evidence of covalent Fe–O bonding. Vibrating sample magnetometry demonstrated superparamagnetic behavior for all samples, with S-CNC/Fe3O4 1:4 and 1:2 displaying saturation magnetizations of 78 and 77 emu/g-Fe3O4, close to the 83 emu/g of bare magnetite. The T-CNC composites showed lower (60 and 66 emu/g-Fe3O4) saturation magnetizations. Zero-field-cooled/field-cooled measurements resulted in a blocking temperature of 112 K for all samples, except T-CNC/Fe3O4 1:2 (100 K). Magnetic hyperthermia studies revealed that specific absorption rate (SAR) increased with field strength and Fe3O4 content; however, S-CNC/Fe3O4 (1:2) achieved the highest intrinsic SAR per gram of Fe3O4(649 W/g-Fe3O4) likely due to its anisotropy and fast magnetic relaxation. Cytotoxicity assays confirmed that all nanocomposites were nontoxic toward mammalian cells. These results establish quantitative structure–property relationships between CNC surface chemistry, interfacial bonding mechanisms, and magnetic heating performance, providing a foundation for rational design of biocompatible magnetic nanocomposites for hyperthermia and related applications.

Document Version

Published Version

Comments

© 2026 The Authors. Link to DOI: https://doi.org/10.1021/acsanm.5c05783

This publication is licensed under CC-BY 4.0.

The authors gratefully acknowledge Dr. Gabriela Romero-Uribe (Department of Biomedical and Chemical Engineering, UTSA) for providing access to the Malvern Zetasizer. We also thank the Kleberg Advanced Microscopy Center (KAMC) at UTSA for their support. Additionally, we appreciate Abul Mansur Muhammed Fahim and Dr. Kirk Schanze (Department of Chemistry, UTSA) for their assistance with the FTIR instrumentation. This work was partially supported by NIFA Grant number 2023-67017-40045 from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Work performed at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, was supported by the U.S. DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Part of the computational work used Expanse at San Diego Supercomputer Center (SDSC) through allocation TG-MAT230085 from the Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) program, which is supported by U.S. National Science Foundation grants #2138259, #2138286, #2138307, #2137603, and #2138296.

Publisher

American Chemical Society

Peer Reviewed

yes

Keywords

Hyperthermia, Magnetic Properties, Metal Oxide Nanoparticles, Nanocomposites, Nanoparticles

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