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Guava for gold

(Clockwise from bottom right) SEM image of the nanoparticles; researchers: A. Venkataraman, S. Y. Manjunath, Raghunandan Deshpande, Mahesh D Bedre and Balaji Sawle.

Gold nanoparticles can be biosynthesised within no time using a new green technology1. Researchers have used microwave-assisted anti-malignant leaf of guava (Psidium guajava) to make polyshaped gold nanoparticles. The method avoids the tedious process associated with making nanoparticles using micro-organisms.

The researchers screened 25 anti-malignant plants including the popular Vinca (Vinca rosea) . They chose guava leaf, also known for its anti-malignant effects, after confirming its potential for further preparation of extract, synthesis of the nanoparticles and for screening. A colloidal solution of bio-functionalised gold nanoparticles was found to be stable even after 30 weeks of storage.

The rate of synthesis of gold nanoparticles with microwave-exposed guava leaf extract was found to be far better than that of other chemical and physical methods with microorganisms and other plants.

The field of gold nanoparticle biosynthesis is leading to new avenues in material science, chemistry, nanobiotechnology and biotechnology. It would be significant to understand the clear mechanism of biosynthesis and technologically engineer the nanoparticles to achieve better control over size, shape, and absolute monodespersivity.



  1. Raghunandan, D. et al. Biosynthesis of Stable Poly-shaped Gold Nanoparticles from Microwave-Exposed Aqueous Extracellular Anti-malignant Guava (Psidium guajava) Leaf Extract. Nanobiotechnology (2009) doi: 10.1007/s12030-009-9030-8

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