Tannic acid-induced interfacial ligand-to-metal charge transfer and the phase transformation of Fe3O4 nanoparticles for the photothermal bacteria destruction

Te Wei Chang, Han Ko, Wei Shiang Huang, Yi Chun Chiu, Li Xing Yang, Zi Chun Chia, Yu Cheng Chin, Ya Jyun Chen, Yi Tseng Tsai, Che Wei Hsu, Chia Ching Chang, Pei Jane Tsai, Chih Chia Huang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

An iron oxide (Fe3O4)-mediated photothermal treatment has been revealed as the next generation of noninvasive and nontoxic theranostic nanoagents compared with other inorganic nanoparticles. Nevertheless, iron oxide with NIR-mediated activity is limited by its inability to be mass produced and its long-lasting photon-to-thermal conversion. Herein, we develop using a green reagent, tannic acid (TNA), which assisted hydrothermal reaction to generate black Fe3O4 nanoparticles by using commercially available nanoptical γ-Fe2O3 NPs as a starting material. The phase transformation from γ-Fe2O3 to the reduced form of Fe3O4 is assisted by TNA in the solution phase. Based on the formation of the interfacial TNA-Fe chelation and the delicate phase transformation from γ-Fe2O3 to Fe3O4 structures, the colloidal black Fe3O4 nanoparticles exhibit broad absorption that covers the visible and NIR wavelengths. Specific interfacial ligand-to-metal charge transfers between the TNA and iron ions at the surface of iron oxide nanoparticles, improves the absorbance and leads to the highest photon-to-thermal conversion (η = 35.7%) at 808 nm compared with other iron oxide nanomaterials. After modifying d-mannose (MA) onto the surface of the Fe3O4@TNA nanoparticles, the local heat can efficiently transfer from the Fe3O4@TNA nanoparticles to the vicinity of the bacterial FimH adhesion molecule, causing extensive photothermal injury to O157:H7 and ESBL strain bacteria with over 99% cell death at 200 ppm[Fe] with 808 nm light at 2.25 mW/cm2. Based on its robust photostability, Fe3O4@TNA@MA shows photothermal bactericidal recyclability through magnetic collection, adhesion, and photothermal processes.

Original languageEnglish
Article number131237
JournalChemical Engineering Journal
Volume428
DOIs
StatePublished - 15 Jan 2022

Keywords

  • Green materials
  • Ligand-to-metal charge transfer
  • Phase transformation
  • Photothermal bactericidal recyclability
  • Tannic acid

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