Antibacterial Activity of Quantum-Confined One-Dimensional Titanate Nanofilaments

The emergence of antimicrobial resistance demands fundamentally new classes of antibacterial materials that operate through mechanisms distinct from conventional chemical or photodynamic pathways. Here, we introduce quantum-confined, one-dimensional lepidocrocite titanate nanofilaments (1DL NFs) as a previously unexplored inorganic nanomaterial platform that inactivates bacteria through direct contact-mediated membrane disruption. The 1DL-Ti NFs exhibit potent antibacterial activity against Escherichia coli, Bacillus subtilis, and Listeria innocua, achieving ∼96-99% inactivation within 4 h under ambient light and ∼85% in the dark, revealing light-independent efficacy. Multiparametric analyses─including reactive oxygen species assays, flow cytometry, and high-resolution electron microscopy─demonstrate a unique physical mechanism by which 1DL NFs result in membrane impalement, cell entrapment, and rapid biofilm-like agglomeration, distinct from ion- or reactive oxygen species-driven bactericidal pathways. Metal-ion release studies confirmed negligible leaching, ruling out ion-mediated toxicity. This "all-surface" architecture, enabled by the atomically thin one-dimensional structure of the NFs, differentiates them from conventional TiO₂ nanocrystals and promotes strong interfacial contact with bacterial membranes. The synthesis is solution-based, low-temperature, highly scalable, and tolerant to the presence of several interlayer cations, providing modularity and manufacturability. These findings establish 1DL NFs as a new class of inorganic antibacterial materials with transformative potential for smart antimicrobial coatings, biomedical interfaces, water purification, and food-safety applications.