1 Investigating the role of shape and size of gold 2 nanoparticles on their toxicities to fungi 3

The possibility of releasing gold nanoparticles (GNP) into the environment has been 9 rapidly increasing with the wide spread and flourishing application of gold nanoparticles (GNPs) 10 in a wide range of areas. Consequently, environmental effects of GNP, especially toxicities to 11 living organisms have drawn great attention. However, their toxicological characteristics still 12 remain unclear. Fungi, as the decomposers of the ecosystem, interact directly with the 13 environment and critically control the overall health of the biosphere. Thus, their sensitivity to 14 GNP toxicity is particularly important. The aim of this study was to evaluate the role of shape and 15 size of GNPs on their toxicities to fungi, which could help reveal the ecotoxicity of GNPs. 16 Aspergillus niger, Mucor hiemalis and Penicillium chrysogenum were chosen for toxicity assessment, 17 and circular and star/flower-shaped GNPs sized from 0.7 nm to large aggregates of 400 nm have 18 been synthesised. After mixed with GNPs and reacting agents of GNPs accordingly and incubated 19 for 48 hours, the relative survival rates of each kind of fungus was calculated and compared. The 20 results indicated that with similar sizes, star/flower-shaped GNPs are more toxic to fungi than 21 circular-shaped GNPs; the toxicity of star/flower-shaped GNPs increases with smaller sizes. The 22 results also showed that different species of fungus reacts differently to same GNPs, and 23 Penicillium chrysogenum was relatively more sensitive under the exposure to GNPs. 24