Bio-Synthesis of Gold Nanoparticles by Fusarium oxysporum and Assessment of Their Conjugation Possibility with Two Types of β-Lactam Antibiotics without Any Additional Linkers

Abstract

In the present study, biosynthesis of gold nanoparticles (GNPs) by Fusarium oxysporum was carried out and their conjugation possibility with two β-lactam antibiotics was evaluated. F. oxysporum was cultured and the fungal culture supernatant was subjected to the 1 mmol final concentration of chloroauric acid solution. The produced GNPs were analyzed using visible spectrophotometer, X-ray diffraction analysis (XRD) and transmission electron microscope (TEM). After the purification of GNPs, they were subjected to penicillin G and ceftriaxone without any additional linkers. Finally, the mixture was analyzed using visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and TEM and subjected to antibacterial activity test using the well diffusion method. Results confirmed the presence of GNPs in the F. oxysporum culture supernatant after the addition of chloroauric acid. TEM results showed that GNPs were spherical and amorphous with sizes around 10–25 nm and XRD confirmed the presence of GNPs in the fungal culture supernatant. After the incubation of GNPs with the antibiotics, FTIR results demonstrated the successful linking of GNPs with the corresponded antibiotics and TEM images showed that GNPs sizes were bigger than the pure ones (around 50–100 nm). Finally the antibacterial activity test indicated that absolutely, the antibacterial properties of the GNPs-β-lactam antibiotics was lowered or not changed in contrast to the pure antibiotics. The present study showed that GNPs had high tendency of conjugation with antibiotics but unlike the previous researches, linking of the antibiotics to GNPs always cannot improve their antibacterial activity based on the antibiotics that were used. The high conjugation affinity of GNPs made them a good candidate as detoxification agent in diverse areas of medicine or environmental sciences.