Scientists searching for safer, non-toxic ways to produce nanoparticles have opened up new avenues of research by mixing ordinary tea with gold salts and water.
Their simple procedure created gold nanoparticles with a stable coating in a single manufacturing step.
Dr. Kattesh Katti's research group at the University of Missouri-Columbia tested these particles with prostate and breast cancer cell lines, finding that there was significant cellular absorption via endocytosis, thus potentially improving nanotechnology delivery systems of drugs to fight cancer.
As well as providing a non-toxic way to generate gold nanoparticles, two catechin phytochemicals in tea (catechin and EGCG) also provided a stable coating for the particles. Epigallocatechin and epicatechin required the addition of gum arabic to achieve a stable coating.
Theaflavins from black tea (Darjeeling) were also effective for both generation and stabilization of the gold nanoparticles (Nune, S et al, Green nanotechnology from tea: phytochemicals in tea as building blocks for production of biocompatible gold nanoparticles, Journal of Materials Chemistry, March-April, 2009, 2912-2920)
Dr. Katti's team is also working with natural biological products like cinnamon, soybeans, and cumin to safely produce, transport, and store effective nanotechnology particles (Nripen Chanda et al, An effective strategy for the synthesis of biocompatible gold nanoparticles using cinnamon phytochemicals for phantom CT imaging and photoacoustic detection of cancerous cells. Pharmaceutical Research, November, 2010).
Researchers in Malaysia have also produced silver nanoparticles from Chinese tea from Camellia sinensis.
X-ray diffraction and transmission electron microscopy show that the silver nanoparticles have a size of 4 nm with a face-centered cubic structure (Loo YY et al, Synthesis of silver nanoparticles by using tea leaf extract from Camellia Sinensis, International Journal of Nanomedicine, August 2012, p 4263-7).
Tea green nanotechnology research and longer nanoparticle stability
Chemical engineers at the University of Kentucky are also developing ways to use green tea to stabilize nanoparticles, thus increasing their effectiveness.
They are working with polymer films that use reactive particles made of iron to degrade a common industrial pollutant called trichloroethylene (TCE).
Normally, iron nanoparticles for this polymer film are synthesized using sodium borohydride as a reducing agent. However, that system leads to rapid oxidation of the useful iron and exhausts the polymer film capacity to degrade TCE within a few cycles.
Tea treated particles can be used repeatedly
When the scientists used green tea instead of sodium borohydride, the subsequent stability of the iron nanoparticles preserved the capacity of the membrane to degrade the pollutant for over 3 months of repeated use, even when tested with real water systems (Smuleac V et al: Green Synthesis of Fe and Fe/Pd Bimetallic Nanoparticles in Membranes for Reductive Degradation of Chlorinated Organics, Journal of Membrane Science. September 2011, p131-137).
Nanotechnology particles are being used in medicine, environment, and space exploration, as well as consumer products available now.
Older production methods have used harmful chemicals and acids which have created hazardous toxic waste.
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This page was last updated by Sharon Jones.
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