In situ grown silver nanoparticles on tetrapod-like zinc oxide whisker for photocatalytic antibacterial in scaffolds

Abstract

Tetrapod-like zinc oxide whisker (T-ZnOw) had aroused great interest in photocatalytic antibacterial due to its unique wurtzite structure and high excitonic restricting vitality. Nevertheless, the poor visible light absorption and rapid electron–hole recombination resulted in unsatisfactory reactive oxygen species (ROS) production efficiency. Herein, silver nanoparticles (AgNPs) were in situ grown on T-ZnOw to form Ag@T-ZnOw nanohybrids and then composited with poly-l-lactic acid (PLLA) powder to prepare Ag@T-ZnOw/PLLA scaffolds by selective laser sintering. On the one hand, AgNPs were expected to enhance the visible light absorption of Ag@T-ZnOw through surface plasmon resonance. On the other hand, AgNPs could act as electrons sink to accelerate photogenerated electrons transfer, thereby inhibiting electron–hole recombination. The UV–vis diffuse reflectance spectra revealed that the visible light absorption of T-ZnOw was enhanced with the introduction of AgNPs. Particularly, the band gap of Ag@T-ZnOw was decreased from 2.99 eV to 2.64 eV, implying that the electron–hole recombination time was prolonged and thereby facilitated to the generation of more ROS. Fluorescence probe measurements confirmed that ROS signal intensity of Ag@T-ZnOw/PLLA increased by 66.7% in comparison with that of T-ZnOw/PLLA, which resulted in the scaffolds exhibiting a robust antibacterial activity and thus offered a great promise for the treatment of implantation-associated infection.