SERS active Au nanoparticles from green syntheses employing extracts of edible plant leaves

We produced gold nanoparticles (AuNPs) by green chemistry syntheses. Tetrachloro (III) auric acid was reduced by aqueous plant extracts at 40 - 70 ºC temperatures. The starting material derived from leaves of higher plants of common, edible species, belonging to four families: Brassica oleracea L. var. capitata and var. italica (Brassicaceae); Cichorium endivia L. and Lactuca sativa L. (Compositae); Apium graveolens L. and Foeniculum vulgare Mill. (Apiaceae); Cucurbita pepo L. (Cucurbitaceae). Single- and double-step synthetic procedures were applied. In all cases the synthesis successfully yielded AuNPs, which were characterized by extinction spectra and TEM imaging 1 hour, 1 week, and 1 month after the reaction. The obtained AuNPs showed a distribution of size and shape which depended on the plant species as well as on the synthetic route, ranging from globular AuNPs to sharp edged aggregates.