Details

Autor(en) / Beteiligte

• Lee, Hye-Eun
• Ahn, Hyo-Yong
• Mun, Jungho
• Lee, Yoon Young
• Kim, Minkyung
• Cho, Nam Heon
• Chang, Kiseok
• Kim, Wook Sung
• Rho, Junsuk
• Nam, Ki Tae

Titel

Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles

Ist Teil von

• Nature (London), 2018-04, Vol.556 (7701), p.360-365

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2018

Quelle

MEDLINE

Beschreibungen/Notizen

• Understanding chirality, or handedness, in molecules is important because of the enantioselectivity that is observed in many biochemical reactions 1 , and because of the recent development of chiral metamaterials with exceptional light-manipulating capabilities, such as polarization control 2 – 4 , a negative refractive index 5 and chiral sensing 6 . Chiral nanostructures have been produced using nanofabrication techniques such as lithography 7 and molecular self-assembly 8 – 11 , but large-scale and simple fabrication methods for three-dimensional chiral structures remain a challenge. In this regard, chirality transfer represents a simpler and more efficient method for controlling chiral morphology 12 – 18 . Although a few studies 18 , 19 have described the transfer of molecular chirality into micrometre-sized helical ceramic crystals, this technique has yet to be implemented for metal nanoparticles with sizes of hundreds of nanometres. Here we develop a strategy for synthesizing chiral gold nanoparticles that involves using amino acids and peptides to control the optical activity, handedness and chiral plasmonic resonance of the nanoparticles. The key requirement for achieving such chiral structures is the formation of high-Miller-index surfaces ({ hkl }, h ≠ k ≠ l ≠ 0) that are intrinsically chiral, owing to the presence of ‘kink’ sites 20 – 22 in the nanoparticles during growth. The presence of chiral components at the inorganic surface of the nanoparticles and in the amino acids and peptides results in enantioselective interactions at the interface between these elements; these interactions lead to asymmetric evolution of the nanoparticles and the formation of helicoid morphologies that consist of highly twisted chiral elements. The gold nanoparticles that we grow display strong chiral plasmonic optical activity (a dis-symmetry factor of 0.2), even when dispersed randomly in solution; this observation is supported by theoretical calculations and direct visualizations of macroscopic colour transformations. We anticipate that our strategy will aid in the rational design and fabrication of three-dimensional chiral nanostructures for use in plasmonic metamaterial applications. Chirality can be ‘encoded’ into gold nanoparticles by introducing chiral amino acids or peptides during the growth process, leading to the formation of helicoid morphologies.