Effect of synthesis, purification and growth determination methods on the antibacterial and antifungal activity of gold nanoparticles.

In recent years, both nanotechnology and the use of nanomaterials have been growing in fields as diverse as biomedicine, food or electronics. Particularly metal nanoparticles, such as gold nanoparticles (AuNPs), are being widely studied with different applications, for example as an antimicrobial agent, in hyperthermic therapy or drug transport. Gold nanoparticles can be synthesized by different methods, such as stand out reduction with citrate or greener methods that use greener reducing agents (e.g. stainless steel). In the present work, both the effect of the synthesis method yielding AuNPs with similar size and purification of AuNPs affect the antibacterial and antifungal activities of the AuNPs obtained by citrate reduction and with stainless steel. The growth curves of the gram-negative (E. coli) and gram-positive bacteria (S. aureus) and the yeast C. albicans were constructed and the cell viability was evaluated by (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT). According to our results, the purification of the AuNPs after their synthesis and the growth determination method affect the antibacterial and antifungal activities while the synthesis method shows no significant differences.