Electron-Withdrawing Hexagonal Boron Nitride as a Biocompatible and Metal-Free Antibacterial Platform

Abstract

Inert hexagonal boron nitride (h-BN) is a prominent two-dimensional material known for its wide bandgap, thermal stability, and biocompatibility, but it resists functionalization due to strong B–N bonds. This study presents a method to fluorinate h-BN via cryomilling, resulting in ∼30 atom % fluorine loading (F-dBN). This modification prevents the formation of C–F bonds associated with adverse health effects, enhances biocompatibility, and introduces electron-withdrawing properties that improve the material’s chemical reactivity and antibacterial efficiency while significantly reducing its bandgap from 5.77 to 3.64 eV. Using a microdroplet electrochemical setup, the charge transfer at the F-dBN-bacterium interface is amplified by osmotic pressure, showing that F moieties enhance extracellular electron transfer and disrupt bacterial charge balance. Notably, F-dBN exhibits >99% antibacterial activity against Escherichia coli, underscoring its potential as a biocompatible antibacterial platform and highlighting the microdroplet electrochemical method’s utility for studying charge transfer dynamics in biological systems.