Time-dependent eco-friendly method to produce Au nanometric assemblies with fluorescent properties

Abstract

A time-dependent eco-friendly synthesis of Au assemblies was carried out using Taraxacum officinale plant extract in the present study. Au nanomaterials have potential applications in imaging therapy cancer diagnostics due to their biocompatibility and fluorescence response when irradiated with Ultraviolet light. Also, synthesis methods whose chemistry minimizes toxic residues are of interest to scientists, mainly when intended to use Au nanomaterials for biomedical treatments. Furthermore, the obtained products' fluorescence intensities were also measured to determine if they could be helpful biosensors. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray diffraction (XRD), Infrared spectroscopy (FTIR), Atomic absorption spectrophotometry (AAS), and Zeta potential (ZP) analyzed the obtained products. SEM shows Au self-assemblies with dendritic morphology and an average size of 158 nm. TEM images also confirm dendrites with flat-flower morphology with a thickness of around 10 nm. UV–Vis spectrum displays surface plasmon resonance (SPR) bands typical of Au nanostructures. XRD results further confirm the Au fcc nanostructure of dendrites. FTIR spectra show that the Au ions reduction compounds were sugars, proteins, and compounds with benzene rings. Also, AAS indicates 89% of conversion efficiency from Au ions to assemblies. Fluorescence analyses show that the Au nanostructures' intensities in 280 u.a. could be significant for widespread applications as fluorescent biosensors in therapy and imaging. Finally, the ZP value for Au assemblies was –26.6 mV indicating good colloidal stability at the end of the reaction.