Chiral 432 Helicoid II Nanoparticle Synthesized with Glutathione and Poly(T)₂₀ Nucleotide

Abstract

Finding a novel method to generate a chiral plasmonic material has been highlighted in the last decades for its unique light‐matter interactions. Recently, an aqueous based peptide directed synthesis of chiral plasmonic gold nanoparticle with exceptional chiroptic response has been reported. Especially, the facile and precise control of chirality using biomolecules allows potential expansion of chiral metamaterial synthesis. In this work, we show a significant enhancement of chiroptic response by simultaneous introduction of multiple bio‐molecular chiral modifiers, glutathione and homooligonucleotide containing thymine. Compared to previously synthesized single chiral plasmonic nanoparticles using only glutathione molecules, further addition of an oligonucleotide into the growth solution induces a two‐fold increase of dissymmetric factor. We believe that the presented synthetic method proposes an effective route of chiral metamaterial morphology and property control for versatile applications.

Nanophotonic Approaches for Chirality Sensing

“…Another strategy to prepare chiral plasmonic nanostructures is directed growth during NP synthesis. ,− Previous studies indicate that different amino acid enantiomers can have different binding energies to the crystal facets of Au. − Thus, NP growth pathways can be controlled using amino acids and small peptides . Nam and co-workers developed a synthesis method based on enantioselective interactions between inorganic surfaces and chiral molecules. , They used l - and d -cysteine as structure-directing agents to synthesize Au helicoids with opposite handedness . The short peptide l -glutathione also produced NPs with highly helical characteristics.…”

“…Chiral nanostructures, such as NPs assembled into chiral geometries, experience larger chiroptical responses than molecules because of their larger absorption and scattering cross sections as a result of the LSPR . Further, coupling between adjacent NPs in chiral arrangements produces chiroptical activity across the entire assembly. ,− Chiral nanostructures are produced via e-beam lithography, , assembly assisted by DNA ,− and other templating materials, ,,− and directed growth during chemical synthesis . Numerous groups have created NP sensors to self-assemble or breakdown in the presence of a chiral analyte, producing a detectable change in CD magnitude. ,, Further, Au nanorods have been shown to aggregate into chiral protein–Au nanorod assemblies − that are promising for applications including fibrillation detection …”

Three-dimensional artificial chirality towards low-cost and ultra-sensitive enantioselective sensing

“…The synthesis of plasmonic nanoparticles with chiral morphologies 23,25–28 is a typical use of bottom-up self-assembly methods, which involves one or two seed-mediated aqueous chemical-reaction procedures. 29 When amino acids and peptides interact enantioselectively with surfaces that have high Miller indices, the atoms tend to arrange on the surfaces with chiral characteristics during growth.…”

Selective Excitation of Polarization‐Steered Chiral Photoluminescence in Single Plasmonic Nanohelicoids

“…With the assistance of cysteine (Cys) and Cys‐based peptides, various three‐dimensional (3D) right‐ and left‐handed chiral and achiral metal NPs can be made. [ 10–13 ] Those chiral plasmonic NPs possess strong circular dichroism (CD) signals with g ‐factors up to 0.2. Such plasmon‐amplified chiroptical responses have been used to enhance and modulate chiral activities of many nanophotonic systems at the single‐particle level.…”