Controlled synthesis of highly-branched plasmonic gold nanoparticles through peptoid engineering

Abstract

In nature, specific biomolecules interacting with mineral precursors are responsible for the precise production of nanostructured inorganic materials that exhibit complex morphologies and superior performance. Despite advances in developing biomimetic approaches, the design rules for creating sequence-defined molecules that lead to the synthesis of inorganic nanomaterials with predictable complex morphologies are unknown. Herein we report the design of sequence-defined peptoids for controlled synthesis of highly branched plasmonic gold particles. By engineering peptoid sequences and investigating the resulting particle formation mechanisms, we develop a rule of thumb for designing peptoids that predictively enabled the morphological evolution from spherical to coral-shaped nanoparticles. Through a combination of hyperspectral UV-Vis extinction microscopy and three-photon photoemission electron microscopy, we demonstrate that the individual coral-shaped gold nanoparticles exhibit a plasmonic enhancement as high as 105-fold. This research significantly advances our ultimate vision of predictive bio-inspired materials synthesis using sequence-defined synthetic molecules that mimic proteins and peptides.

Design of plasmonic nanomaterials for diagnostic spectrometry

“…13,26,27 The controllable size and shape of these particles can be tailored by optimization of synthetic conditions, such as stabilizing agents, 28,29 surface functionalization 15,30 and temperature variations. 24,29 Plasmonic nanomaterials are most commonly synthesized using chemical methods such as citrate/borohydride/ascorbic acid reduction, 14,30,31 hydrothermal reactions, 32 light-mediated processes, laser/g-ray/electron beam irradiation, and lithography. Nanomaterials prepared through physical methods involve the deposition of thin lms by condensing atomized elements or components by vapour evaporation or sputtering.…”

“…(A) Schematic of Pep-1-induced formation of spherical coral-shaped gold nanoparticles and TEM images demonstrating the monodispersity of the nanoparticles. Reproduced with permission 30. Copyright 2018, Nature Publishing Group.…”

Peptoids as tools and sensors

“…Yan et al . were able to develop a rule‐based peptoid sequence design for the manipulation of a soluble gold precursor to create highly‐branched plasmonic gold nanoparticles (from hydrogen tetrachloroaurate (III) (HAuCl 4 )).…”

Peptoid-based hierarchically-structured biomimetic nanomaterials: Synthesis, characterization and applications

“…This subtle structural modification provides peptoids with unique structures and properties in contrast to peptides and proteins, such as high stability against protease digestion, enhanced chemical and thermal stability, and the lack of backbone hydrogen bond donors which simplifies the building of peptoid-peptoid and peptoid-surface interactions exclusively through side-chain chemistry. Because of such advantages, in the last several years, amphiphilic peptoids have been frequently designed and used as sequence-defined building blocks to assemble into biomimetic nanomaterials with various hierarchical structures both on the substrate surfaces and in the solution [1,2,[7][8][9][10][11][12][13][14][15][16][17][18]. To access sequence-defined peptoids, a step-wise "sub-monomer" synthesis approach was developed by Zuckermann et al [19] in 1992.…”