Photodeactivation of pathogenic bacteria using graphene quantum dots synthesized by nanosecond laser pulses

In this work, a graphene-based biomaterial which is a promising alternative to a standard photosensitizers was produced and its efficiency of bacteria inactivation was studied. Graphene quantum dots (GQDs) were synthesized by irradiating benzene and nickel oxide mixture using nanosecond laser pulses. High-resolution transmission electron microscopy (HR-TEM) results show GQDs whose size less than 5 nm with very good water dispersibility were successfully obtained. UV-Vis spectra of GQDs have an absorption peak around 300 nm and photoluminescence spectra shows that GQDs have maximum emission at 430 nm with the excitation wavelength of 310 nm. Also, Fourier transform infrared (FTIR) spectra further confirms the presence of GQDs. Deactivation of Escherichia coli (E. coli) a gram-negative bacterium with a photosensitizer and carbon nanoparticles was studied by irradiating with different wavelengths. The results show a significant decrease in the number of colony forming units of E. coli. Our results show that GQDs can potentially be used to develop therapies for the eradication of pathogens in open wounds, burns, or skin cancers.