Fluorescent amikacin modified nitrogen, sulfur co-doped carbon dots (amikacin modified N,S-CDs) were synthesized by a facile and low-cost one-step microwave-assisted specifically for selective detection of Gram-negative bacteria Escherichia coli (E. coli). Amikacin is a semi-synthetic amino glycoside antibiotic and it was employed in this study to increase the fluorescence response of N,S-CDs by providing binding ligand towards E. coli. The effect of thiourea content as the source of nitrogen and sulfur dopants was investigated prior to the preparation of amikacin modified N,S-CDs. The formation of amikacin modified N,S-CDs were characterized by using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Transmission electron microscope (TEM), UV-Vis spectrophotometer, and spectrofluorometer. Amikacin modified N,S-CDs was identified to be successfully synthesized from the wavenumber shift of the C=O stretching mode. Amikacin modified N,S-CDs were amorphous with an average size of 7 nm. Fluorescence spectra showed that the highest intensity was obtained at thiourea content of 50% and amikacin mass of 25 mg. By comparing fluorescence responses of all the investigated amikacin modified N,S-CDs, the limit of detection (LOD) was attained by 25 mg amikacin modified N,S-CDs at 1.526 cfu mL−1.
Ultrafast ammonia-driven, microwave-assisted synthesis of nitrogen-doped graphene quantum dots and their optical properties