This study proposes a strategy for the rapid and simple synthesis of gold nanoparticles (CGA-AuNPs) with different particle size using trisodium citrate (TSC) as the first reducing agent and chlorogenic acid (CGA) as the second reducing agent. And the antibacterial activity of CGA-AuNPs with different particle size in vitro was verified by measuring the growth curves of Escherichia coli (E. coli ATCC 25922) and Staphylococcus aureus (S. aureus ATCC 25923). The CGA-AuNPs obtained by analysis of transmission electron microscope (TEM) images and UV-visible Spectra were mainly spherical, and the average diameters were 18.94±1.81nm, 30.42±6.32nm, 37.86±3.80nm, 48.72±6.47nm respectively. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) showed that these nanoparticles were polycrystalline gold structures. Both of CGA-AuNPs and CGA have excellent antibacterial activity, and CGA-AuNPs with small particle size has a stronger antibacterial effect than the larger one. UV-visible absorption spectrum data revealed that the synthesized CGA-AuNPs without adding other stabilizing agent were well maintained even after 26 days. This work provides a special idea to regulate the size of CGA-AuNPs with CGA by chemical synthesis, and the strong antibacterial activity of these CGA-AuNPs may be applied in the field of antibacterial in the future.

Data underlying figures 1-3, 5-7 of the associated paper