Naslov
Adsorption of polyamino acids and their influence on the precipitation of calcium carbonate polymorphs

Autori
Njegić, Branka ; Kralj, Damir ; Falini, Giuseppe ; Brečević, Ljerka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
The 2004 Younger European Chemists' Conference. Highlights of European Chemical Research and R&D in 2004 / Wharton, Eric - Torino : Societa Chimica Italiana, 2004

Skup
The 2004 Younger European Chemists' Conference

Mjesto i datum
Torino, Italija, 25.08.2004. - 29.08.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Calcium carbonate; Calcite; Vaterite; Polyamino acids; Precipitation
(calcium carbonate; calcite; vaterite; polyamino acids; precipitation)

Sažetak
Molluscs shells, egg shells, pearls and corals are natural biocomposites in which calcium carbonate is the principal mineral component. Mechanical properties of these materials are the consequence of oriented crystallization, polymorphism and/or morphology of the calcium carbonate crystals induced by the organic matrix containing polypeptides reach in acidic amino acid residues (aspartic and glutamic acid). The aim of this work was to investigate the effect of poly-L-aspartic acid (pAsp) and poly-L-glutamic acid (pGlu) on the nucleation and crystal growth of calcium carbonate polymorphs, calcite and vaterite. Poly-L-aspartic acid and poly-L-glutamic acid were chosen as model molecules, of known composition and structure, to mimic the natural acidic polypeptides. Two types of experiments were conducted: spontaneous precipitation and precipitation initiated by introduction of seed crystals of calcite or vaterite at t=25 &ordm ; C. The precipitation process was followed by recording pH as a function of time. Samples were characterized by means of FT-IR spectroscopy, optical and scanning electron microscopy. It was found that both synthetic polypeptides, pAsp and pGlu, inhibited nucleation as well as crystal growth of calcite and vaterite. On the contrary, basic polypeptide poly-L-lysine had no influence on the precipitation of any of the polymorphs. It could be concluded that specific adsorption of pAsp and pGlu onto the surface of the growing crystals is responsible for the inhibition effects and the assumption was confirmed by fluorescence microscopy and electrophoretic mobility measurements.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA