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

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 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.