EN
A potential non-destructive harvesting of gold nanoparticles (Au NPs) employing the seed
shell and detoxified-defatted seed meal aqueous extracts of Jatropha curcas is reported. The
reduction potential of the shell and meal extracts were tested at varied ratios with chloroauric
acid under physical parameters of increasing pressure and temperature. The optimal ratio
of chloroauric acid to seed meal/shell extracts was determined to be 1:1 under constant
shaking in water bath at 60ºC yielding nearly isotropic nanoparticles, which was confirmed
by UV-Vis spectroscopy, HRTEM and AFM analysis. With increasing concentrations (1:2, 1:3,
1:4) of reducing agents, temperature (121ºC) and pressure (12 lbs), anisotropy with respect
to particle shape and size increased in order. FT-IR, TGA and HRTEM provided evidence of
bio-capping of the nanoparticles with biomolecules present in the parent reducing sources.
The biocompatibility of these nanoparticles was tested on neuronal HCN-1A and brain cancer
glioma Gl-1 cell lines, which revealed their superior cyto-amiability when compared with
conventionally synthesized Au NPs. The biodiagnostic and photothermal ablation potential
of the Au NPs were also tested and affirmed with the luminescent signals recorded from the
cellular cytoplasm indicating the efficient internalization of these nanoparticles as well as the
apoptotic events encountered upon irradiating the cells with laser. Nearly 100% of the cells
underwent sudden apoptosis within 1 min of laser treatment, providing enough evidence
for the thermal ablation potential of the Au NPs. To support the claim of non-destructive
harvesting of nanoparticles, the protein and ash content of the seed meal and seed shell,
respectively, were analyzed before and after the aqueous extraction. Minimal loss in these
inherent characteristic potentials of the seed meal and shell emphasizes the sustainable
utilization of bio-resources achieved in this report.