Natural extracts eliminate the need for industrial chemical reductants in the formation of gold nanoparticles

(Nanowerk News) With nanotechnology and related advanced technologies emerging at a rapid pace, both in developed and developing countries, the stress on the availability of raw materials is immense.The rapid industrialization of emerging economies, has intensified competition for raw materials, especially those of biological origins. In many cases, the biological sources used for these purposes are partially or completely used up, which may lead to their shortage and possibly create a void in the ecosystem within the near future. Therefore, it is more important than ever to strike a balance between the industry and raw materials.
In the article published last week in Nanomaterials and the Environment ("Non-Destructive Harvesting of Biogenic Gold Nanoparticles from Jatropha curcas Seed Meal and Shell Extracts and their Application as Bio-Diagnostic Photothermal Ablaters-Lending Shine to the Biodiesel Byproducts"), an open access journal by Versita, Prof. Sakthi Kumar and his team from the Bio-Nano Electronics Research Center at Toyo University in Japan, propose an uncomplicated alternative to acquiring renewable sources of reducing agents for the synthesis of nanoparticles.
The scientists report a possible non-destructive approach for the synthesis of gold nanoparticles employing the seed shell and detoxified-defatted seed meal aqueous extracts of Jatropha curcas. The gold nanoparticles prove highly biocompatible with excellent biodiagnostic and photothermal properties. Crucially, they observed a minimal loss in the inherent characteristic potentials of the seed meal (protein) and shell (ash content) which underlines the sustainable usage of bio-resources achieved with this approach.
The large quantity of reducing sources thus obtained is highly eco-friendly and it doesn’t involve the use of any chemicals. In addition to initiating a trend towards sustainable usage of bio resources, the parent biological sources, which are in fact byproducts of the Jatropha curcas biodiesel industry, preserve their original characteristics, thereby increasing their economic viability. The biological sources, seed shell and meal were efficiently used to synthesize gold nanoparticles without compromising their inherent potentials, subsequently elevating their economic prospects. These gold nanoparticles were almost uniform in shape and size and they exhibited excellent biodiagnostic and photothermal properties against human neuronal and glioblastoma brain cancer cells. The ash content of the seed shells and the protein content of the seed meal remained almost identical after the extraction process.
Commenting on the research results, Dr. Raymond Whitby, Head of the Nanoscience and Nanotechnology Group and the Global Education Outreach in Science, Engineering and Technology (GEOSET), says: "The use of natural extracts to drive reduction of metal solutions to form metal nanoparticles is seen as a positive step towards responsible development of green technologies. Prof Kumar and colleagues have wonderfully demonstrated that the extracts from Jatropha curcas not only produced size and geometry controlled gold nanoparticles, but also showed that the gold nanoparticles displayed superior “cyto-amiability” compared with other gold nanoparticles produced by conventional chemical means as well as determining no apparent destruction of the seed. The approach to versatile uses of natural products in nanoscience has taken a big step forward.”
Though lucrative, due to the eco-compatibility and high cost efficiency, most bio-mediated nanoparticle synthesis strategies usually involve destruction of the parent biological source viz., plants, microorganisms or their components. The abundance of bio-resources accounts for such an approach, but in the long term, proves unsustainable. Moreover, it also restricts the economic prospects of the source. Kumar report, however, bypasses the conventional approach of such a destructive route to tread a path where the harmony between natural amenities and their application is both justified and judicial.
The commercial value of the byproducts (shell and meal) will definitely be enhanced, and this method could also indirectly advance the commercial prospects of the Jatropha curcas biodiesel industry, which is already turning into a lifeline industry of many developing nations. Experts expect it to become a high prospect alternative energy source. As a result, we can anticipate a shift towards more sustained and judicial usage of available bio-resources.
Source: Versita