Evaluation of the physicochemical properties of graphene nano quantum dots and their in vitro antibacterial effects on Pseudomonas aeruginosa and Staphylococcus aureus

Abstract

Introduction: In recent years, attention has been paid to new drug delivery systems such as anomedicines for the treatment of diseases. Today, nanoparticles have found wide applications. Objective: Evaluation of the physicochemical properties of graphene nano quantum dots and their in vitro antibacterial effects on Pseudomonas aeruginosa and Staphylococcus aureus.Methods: In this research, the physicochemical properties of graphene nanoquantum dot were investigated in terms of particle size, zeta potential, polydispersity index, and appearance. Also, the crystal properties of nanoquantum were investigated using XRD and FTIR. In order to study the antimicrobial effect of nano quantum dot graphene, the diameter of the halo of no growth was determined by welling method. The minimum growth inhibitory concentration (MIC) against Pseudomonas aeruginosa and Staphylococcus aureus was determined by serial dilution method in liquid culture medium. Next, the amount of MBC was checked, and finally, the death time of Pseudomonas aeruginosa and Staphylococcus aureus cells was studied using the time kill study method.Results: The average particle size was 5.25 nm and the zeta potential was -16.8 mV. Based on the results of TEM, the graphene nano quantum dots were in the nano range and spherical in appearance. XRD and FTIR data show that N-GQDs are molecules with an amorphous structure and they have different polar groups such as carboxyl, hydroxyl and alkyl. Determining the diameter of inhibition zone by welling method showed that the effect of quantum dots against Pseudomonas aeruginosa and Staphylococcus aureus is less than amikacin (as a standard) but comparable to it. The lowest growth inhibitory concentration (MIC) for Pseudomonas aeruginosa and Staphylococcus aureus is 4 mg/cc, and the minimum lethal concentration (MBC) is 8 mg/cc.Conclusion: Graphene quantum dots have good antimicrobial effects comparable to the standard antibiotic (Amikacin) against two pathogenic bacteria, i.e. Pseudomonas aeruginosa and Staphylococcus aureus.