Abstract

The interaction of gold nanoparticles (AuNPs) withcysteine and its derivatives is the basis of a number of bionanotechnologies,and for these, the most important process is aggregation (orantiaggregation), which enables an array of colorimetric detection methods.When AuNPs were functionalized with cysteine, its dimer cystine, or thecysteine-derived tripeptide, glutathione, three different mechanisms ofaggregation were observed. Both cysteine and glutathione inducedaggregation of AuNPs without further pH modification: the first byinterparticle zwitterionic interaction and the second by interparticlehydrogen bonding. Cystine, however, did not induce aggregation, althoughit dissociated into two cysteinate moieties upon adsorption on the AuNPs,which appear to be chemically identical to cysteinate produced from cysteine adsorption. We show that the difference is due tothe lower coverage of cysteinate from cystine and differences in charge states of the adsorbates. On modifying the pH to 1.5, thesurface species become cationic (neutral COOH and protonated NH3+), and aggregation of cystine/AuNPs occurs immediatelyby interparticle hydrogen bonding. Thus, cysteine may induce aggregation by neutral hydrogen bonding or zwitterionicinteraction between nanoparticles, but the mechanism depends sensitively on a number of parameters.

Autore Pugliese

• Carlino Elvio

Tutti gli autori

• Acres R.G.; Feyer V.; Tsud N.; Carlino E.; Prince K.C.

Titolo volume/Rivista

Journal of physical chemistry. C.

Anno di pubblicazione

2014

ISSN

1932-7455

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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