Biosynthesis of metallic nanoparticles is reported as a clean, non toxic and environmentally acceptable route, using different plant extracts [1, 2], bacteria, yeast or fungi [3, 4]. These reports mainly describe nanoparticle formation as a consequence of the Au(III) to Au(0) reduction within plant tissues or cells. In this context we have wondered if could exist any specific metal-plant active component adduct during the nanoparticle biosynthesis. For this purpose, we have chosen to use two active components, extracted from the Cape aloe plant, aloin A and aloesin, as stabilizing agents for gold and silver nanoparticles. Varying the reaction conditions (temperature, reaction time and reducing agent) stabile, water soluble particles of different sizes (4-45 nm) and shape (spherical, triangular and hexagonal) have been prepared. In particular the use of citric acid (1 M) as reducing agent led to a mixture of differently shaped aloin A or aloesin coated gold nanoparticles. The mixture consisted of spherical (50 nm) and large triangular or truncated triangular nanoparticles. Prior to characterization, the aloin A and aloesin coated gold particles were purified of excess ligand by dialysis, in the case of small-sized particles (<10 nm), while lager ones have been purified by centrifugation at different speed depending on the particle size. Gold particles have been fully characterized using UV-vis, ATR-FTIR and 1H and HR-MAS NMR spectroscopy and TEM. The interaction of aloin A and aloesin with the gold particle surface has been investigated by spectroscopic techniques in solution and in the solid state, as well. In solution, we have found that gold particles resulted stabilized by the coordination of glucose OH moieties (Figure 1c), which are present in both molecules investigated, while in the solid state, π electronic interaction plays an additional important role in gold stabilization. Since Cape aloe plant has been investigated as a potential anticancer agent , we have studied the cellular uptake of these hybrid materials into macrophage and HeLa cells, using Confocal and Fluorescence microscopy (Figure 1a-b). The uptake into macrophage cells is an important result, since macrophages plays an important role in the tumour angiogenesis  and aloin A/aloesin coated gold particles are able to carry active principles into the cell. Aloin A and aloesin coated gold particles represent novel bioactive nano-carriers able to carry active principles into the cell and propose these particles as potential anticancer nanovehicles.
|Titolo:||Gold particle stabilization by Cape aloe active components|
|Data di pubblicazione:||2009|
|Settore Scientifico Disciplinare:||Settore CHIM/03 - Chimica Generale e Inorganica|
|Enti collegati al convegno:||Società chimica italiana|
|Citazione:||Gold particle stabilization by Cape aloe active components / Ž. Krpetić, G. Scarì, F. Porta. ((Intervento presentato al 23. convegno Congresso SCI tenutosi a Sorrento nel 5-10 luglio 2009.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|