Specific functionalization of CTAB stabilized anisotropic gold nanoparticles with polypeptides for folding-mediated self-assembly

Abstract

Anisotropic nanoparticles stabilized by cetyltrimethylammonium bromide (CTAB) are notoriously difficult to homogenously functionalize using conventional gold-thiol chemistry. Using surface assisted laser desorption time of flight mass spectroscopy and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, we demonstrate that silver species adsorbed on the particle surface prevent 10 effective surface functionalization. When covered by a thin gold film, particle functionalization was drastically improved. A thiol-containing polypeptide was immobilized on arrowhead gold nanorods (NRs) and was subsequently able to selectively heteroassociate with a complementary polypeptide resulting in a folding-mediated bridging aggregation of the NRs. Despite using arrowhead NRs with a pronounced difference in surface arrangement on the {111} facets on the arrowheads compared to the 15 {100} facets at the particle sides, the polypeptides were efficiently and homogeneously immobilized on the particles after gold film overgrowth.

Stabilization and Encapsulation of Gold Nanostars Mediated by Dithiols

“…We postulate that the role of CTAC is the effective stabilization of the colloidal system, since AuNS capped with CTAC only display a narrow LSPR band (no aggregation) but signifi cantly blueshifted because of reshaping ( Figure 1 ). This synergistic effect combing the attributes of both the thiolated ligand and the surfactant was observed not only for gold nanostars, but also for gold nanospheres, [ 23 ] arrowhead gold nanorods (polypeptide-SH and CTAB), [ 28 ] or standard nanorods (PEG-SH and CTAB). [ 29 ] The stability of BDTmodifi ed AuNS in CTAC is in fact surprising, as in general dithiol ligands are likely to promote bridging of Au NPs into aggregates, but obviously the presence of CTAC screens the potential binding of BDT with AuNS, and ultimately endows signifi cant colloidal stability to the system.…”

Selective detection of Mg2+ ions via enhanced fluorescence emission using Au–DNA nanocomposites

“…1 [22–24]. The shift in λ max was 13 nm and 28 nm for transversal and longitudinal peaks, respectively.…”

Oligopeptide Helical Conformations Control Gold Nanoparticle Cross‐Linking

“…For instance, it has been shown to regulate the cellular uptake of the nanoparticles . Induction of a helical conformation by interaction of a peptide with AuNPs has been reported, as well as the use of designed peptides to induce aggregation . However, in all the above cases, the aggregation is due to the interaction with peptides with which the nanoparticles had been functionalized.…”