Gold nanoparticles (GNPs) have different usage in the medical field. The plan of the present research was to evaluate the influence of the biologically produced GNPs on some rat organs. GNPs were produced using Fusarium oxysporum and their presence was confirmed using spectrophotometer, transmission electron microscope (TEM) and X-ray diffraction (XRD) analyses. The non-toxic and toxic doses of GNPs were determined using MTT assay and were injected intraperitoneally into rats in 3 continuous days and their effects on the kidney, liver and testis were analyzed using microscopic technique. Results revealed that GNPs that were produced had 525 nm absorbance peak and average sizes of about 50 nm, with round and hexagonal shapes. Results from the XRD analysis showed the presence of GNPs in the reaction mixture. MTT assay results revealed that GNPs had somehow toxic effects which depend on their doses. Histological examinations indicated that based on the tested organ, the distribution and effects of GNPs were different which in the testis, the non-toxic dose had no effects and in some parts of the liver and kidney, it induced mild changes. The toxic dose of the GNPs in all the three tested organs induced mild changes. In conclusion, the in vitro and in vivo behaviors of the produced GNPs were different and GNPs even in high concentration induced low changes in the rat organs. This may be due to the short exposure and the use of the biologically produced GNPs.

Hyaluronic acid (HA) is a mucopolysaccharide with different applications in the medicinal field. Since HA does not have antibacterial property, in this research a bacterium with both abilities of HA and silver nanoparticles (SNPs) production was used; HA containing SNPs (HA/SNPs) was obtained and the toxic effect of HA/SNPs was achieved using Limulus Amebocyte Lysate (LAL) and 3-(4,5 dimethyl thiazol-2yl)-2,5 diphenyl tetrazolium bromide (MTT) assays. HA and SNPs were produced separately by Streptococcus pyogenes. Then HA was analyzed using fourier transform infrared (FTIR) spectroscopy and transmission electron microscope (TEM), and SNPs were analyzed using TEM and X-ray diffraction analysis (XRD). In order to produce HA/SNPs complex, SNPs were added to the supernatant containing HA and the complex was precipitated using isopropyl alcohol. HA, SNPs, and HA/SNPs were used for the antibacterial assay. Results proved the formation of HA and SNPs in the bacterial culture medium. SNPs sizes were around 5–30 nm and entered in the structure of HA. Antibacterial test showed that unlike the pure HA, SNPs and HA/SNPs had antibacterial activity. LAL and MTT assays results showed that HA/SNPs had low and dose-dependent toxic effects. In future, the use of HA/SNPs scaffold in tissue engineering field is expected.