Barium hexaferrite nanoplatelets with polyphenol coatings for versatile applications as a stable, magnetic, and antimicrobial colloid

Colloidal stabilization of magnetic nanoparticles is one of the most important steps in the preparation of magnetic nanoparticles for potential biomedical applications. A special kind of magnetic nanoparticle are barium hexaferrite nanoplatelets (BSHF NPLs) with a hexagonal shape and a permanent magnetic moment. One strategy for the stabilization of BHF in aqueous media is to use coatings. In our research, we used an eco-friendly tannic acid, as a coating on BSHF NPLs. As-prepared BSHF NPLs coated with tannic acid were examined with transmission electron microscopy, infrared and UV-Vis spectroscopy, electro-kinetic measurements, and their roomtemperature magnetic properties were measured. Stable colloids were tested in two biological complex media and antimicrobial properties of the material were examined. To enhance the antimicrobial properties of our material, we used tannic acid as a platform for the in-situ production of silver on BSHF NPLs. New hybrid material with silver also possesses magnetic properties and excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus.

Automated summary

Colloidal stabilization is crucial for the preparation of magnetic nanoparticles for biomedical applications. In this study, tannic acid was used as a coating for barium hexaferrite nanoplatelets (BSHF NPLs) to achieve stability in aqueous media. The coated BSHF NPLs were characterized and their magnetic properties were measured. The stable colloids were tested in biological media, and the antimicrobial properties were examined. To enhance antimicrobial activity, tannic acid was used as a platform for the in-situ production of silver on BSHF NPLs. The hybrid material exhibited magnetic properties and excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus.