Synergistic Photodynamic Action and Alkyl Chain Engineering of AIE-Active Cationic Fluorescent Dyes for Antibacterial Textile Applications

Abstract

Photodynamic antibacterial fabrics are crucial for public health via efficient, durable antimicrobial protection. Herein, two series of triphenylamine (TPA)-based aggregation-induced emission (AIE)–active cationic fluorescent dyes were rationally designed and synthesized, integrating acceptor engineering and alkyl-chain engineering for textile functionalization. Based on acceptor engineering, TPPy-C2 with cationic pyridine exhibited the highest fluorescence intensity and reactive oxygen species (ROS) yield. Furthermore, based on alkyl-chain engineering, TPPy-C8 with octyl showed the best antibacterial activity against both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Acrylic fibers were dyed using AIE cationic dyes to prepare dyed fabrics. Compared with commercial Basic orange 22, the efficient generation of ROS and the optimized alkyl chain length of TPPy-C8-F synergistically enhanced both bacterial adhesion and ROS-mediated damage, which exhibited excellent antibacterial activity. Not only does TPPy-C8-F have satisfactory wash fastness and rubbing fastness, but its mechanical properties remain almost unchanged after being exposed to light for 30 min. This work not only provides a new perspective on the construction of cationic dyes with photodynamic antibacterial properties but also provides a promising strategy for the fabrication of multifunctional antibacterial textiles.