Site-specific adsorption of gold nanoparticles coated with thermo-responsive peptides

Abstract

A thermo-responsive elastin, elastin-like peptide (ELP)-gold nanoparticle (AuNP) hybrid (ELP-AuNP), was successfully prepared via the in situ reduction of HAuCl 4 in the presence of lipoic acid-terminated ELP: (VPGVG) 4 (V:valine, P:proline, G:glycine) synthesized using a solid-phase peptide synthesis method. The conformation and aggregation properties of the ELP-AuNP in an aqueous buffer solution were examined using circular dichroism (CD) and ultraviolet-visible (UV-Vis) spectroscopies and transmission electron microscopy (TEM) observation. The phase transition of the ELP layer at the periphery of the AuNP because of the conformational change from random coil to b-turn structures was found to proceed gradually with increasing temperature and to simultaneously cause an aggregation of the ELP-AuNP because of the component's hydrophobic interactions and a color change of the solutions from red to violet. The ELP-AuNPs were aligned selectively onto patterned, hydrophobic polystyrene stripes on a glass plate when the plate was immersed and incubated in the solution containing the ELP-AuNP above its phase transition temperature, as verified using atomic force microscopy (AFM) and scanning electron microscopy (SEM).

Fabrication of Thermo-Responsive Molecular Layers from Self-Assembling Elastin-Like Oligopeptides Containing Cell-Binding Domain for Tissue Engineering

“…Therefore, the thermo-induced conformational transition from the hydrophilic random coil to hydrophobic β-turn is considered to play an important role in aligning RGDS-ELP on a hydrophobic surface via directed assembly. Similar thermo-induced self-adsorbing behavior of oligo(ELP) was observed in our previous study [28], at which the amount of self-adsorption of oligo(ELP)(n = 20)-coated gold nanoparticle for the hydrophobic glass plate was larger than that for hydrophilic one by a factor of ca. 6.…”

“…Recently we have reported an effective and facile method for gold nanoparticle arrays guided by thermo-responsive oligo(ELP) [28]. Using such smart character of oligo(ELP) as a molecular guide, the 2D-organization of bio-functional groups will also be accomplished.…”

“…A pentad repeat (VPGVG)n (n = 4) that provides sufficient chain length to cause a conformational change in response to a thermal stimulus [28,29,31,32] was chosen as the oligo(ELP) segment. We also expected that the mobility of surface-attached RGDS-epitopes would increase by introducing hydrophilic and flexible short deg-linker.…”

“…In previous studies, we have shown that poly(ethylene glycol) (PEG)-modified oligo(ELP)s perform self-assembly into spherical micelle-like aggregates in water in response to the conformational switches of oligo(ELP) segment [27]. The oligo(ELP)-coated gold nanoparticles have been also successfully prepared and selectively aligned onto the 2D-patterned hydrophobic substrate guided with the oligo(ELP) character [28]. More recently we have reported the unique thermo/pH dual-responsive materials from oligo(ELP)-shelled poly(amido-amine) dendrimer [29] and oligo(ELP)-grafted linear polyions [30].…”

Mimicking Adhesion in Minimal Synthetic Cells

“…This allows assemblies of one component to coexist with assemblies of another component without interacting with each other. [79,80] 2) Asocial self-sorting: Self-complementary and homophilic interactions lead to asocial (or narcissistic) self-sorting in which each type of colloid assembles into isolated aggregates. [76] Different forms of self-sorting are possible depending on the type of interactions between cell mimetics.…”