Morphology matters in the antibacterial performance of copper Nanoparticles@fullerenol composites

Abstract

Fullerene (C₆₀) has been considered as feasible antibacterial agent due to the photodynamic therapy (PDT) effect. Nevertheless, the upgradation of its antibacterial power remains an issue to be solved. Since morphological structure affects the antimicrobial performances of nanomaterials, a thorough investigation of morphology-antibacterial property of C₆₀ composites becomes important. Herein, copper nanoparticles (CuNPs) decorated fullerenol (hydroxylated C₆₀) composites (CuNPs@fullerenol) with four morphologies (irregular, flake-like, spherical and acicular) were facily synthesized via liquid-liquid interface precipitation (LLIP) along with photochemical reduction, whose antibacterial effects were obviously different with each other and strongly related to their morphologies. It has been proved that sample sharpness was a decisive factor in its antimicrobial performance under dark condition. In contrast, production efficiency of PDT-induced reactive oxygen species (ROS, e.g. ¹O₂ and •O₂⁻) became critical when composites were illuminated by visible light. The specific surface area and bandgap of CuNPs@fullerenol were further confirmed as key points affecting the yield of ¹O₂ and •O₂⁻. The findings provide possibility of enhancing the antibacterial properties of C₆₀-involved nanomaterials simply by morphology modulation.