Tuning of Morphology by Chirality in Self‐Assembled Structures of Bis(Urea) Amphiphiles in Water

Tosi, Filippo; Berrocal, José Augusto; Stuart, Marc C. A.; Wezenberg, Sander J.; Feringa, Ben L.

doi:10.1002/chem.202003403

“…21 The group of Feringa designed a chiral bis(urea) amphiphile, whose morphology can be programmed to assemble into flat sheets, helical ribbons, and twisted ribbons. 22 These nanostructures also showed thermoresponsive behavior. 23 Phenylalanine (F), tyrosine (T), and tryptophan (W) are intriguing to study because their aromatic side chains can participate in π−π interactions.…”

Section: ■ Introductionmentioning

confidence: 98%

“…Notably, the melting point of the assemblies was independent of the alkyl chain length due to the urea H-bond interactions dominating the thermodynamics . The group of Feringa designed a chiral bis(urea) amphiphile, whose morphology can be programmed to assemble into flat sheets, helical ribbons, and twisted ribbons . These nanostructures also showed thermoresponsive behavior…”

Section: Introductionmentioning

confidence: 99%

Urea-Modified Self-Assembling Peptide Amphiphiles That Form Well-Defined Nanostructures and Hydrogels for Biomedical Applications

Xing

¹

,

Rodger

²

,

Comer

³

et al. 2022

ACS Appl. Bio Mater.

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Hydrogen bonding plays a critical role in the self-assembly of peptide amphiphiles (PAs). Herein, we studied the effect of replacing the amide linkage between the peptide and lipid portions of the PA with a urea group, which possesses an additional hydrogen bond donor. We prepared three PAs with the peptide sequence Phe-Phe-Glu-Glu (FFEE): two are amide-linked with hydrophobic tails of different lengths and the other possesses an alkylated urea group. The differences in the self-assembled structures formed by these PAs were assessed using diverse microscopies, nuclear magnetic resonance (NMR), and dichroism techniques. We found that the urea group influences the morphology and internal arrangement of the assemblies. Molecular dynamics simulations suggest that there are about 50% more hydrogen bonds in nanostructures assembled from the urea-PA than those assembled from the other PAs. Furthermore, in silico studies suggest the presence of urea−π stacking interactions with the phenyl group of Phe, which results in distinct peptide conformations in comparison to the amide-linked PAs. We then studied the effect of the urea modification on the mechanical properties of PA hydrogels. We found that the hydrogel made of the urea-PA exhibits increased stability and self-healing ability. In addition, it allows cell adhesion, spreading, and growth as a matrix. This study reveals that the inclusion of urea bonds might be useful in controlling the morphology, mechanical, and biological properties of self-assembled nanostructures and hydrogels formed by the PAs.

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Spontaneous Formation of Polymeric Nanoribbons in Water Driven by π–π Interactions

Berruée,

Guigner,

Bizien

et al. 2024

Angewandte Chemie

0

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A simple method was developed to produce polymeric nanoribbons and other nanostructures in water. This approach incorporates a perylene diimide (PDI) functionalized by hydrophilic triethylene glycol (TEG) as a hydrophobic supramolecular structure directing unit (SSDU) into the core of hydrophilic poly(N,N‐dimethylacrylamide) (PDMAc) chains using RAFT polymerization. All PDI‐functional polymers dissolved spontaneously in water, forming different nanostructures depending on the degree of polymerization (DPn): nanoribbons and nanocylinders for DPn = 14 and 22, and spheres for DPn > 50 as determined by cryo‐TEM and SAXS analyses. UV‐VIS absorption spectroscopy was used to monitor the evolution of the PDI absorption signal upon dissolution. In solid form, all polymers show a H‐aggregate absorption signature, but upon dissolution in water, the shortest DPn forming nanoribbons evolved to show HJ‐aggregate absorption signals. Over time, the J‐aggregate band increased in intensity, while cryo‐TEM monitoring evidenced an increase in the nanoribbon’s width. Heating the nanoribbons above 60 °C, triggered a morphological transition from nanoribbons to nanocylinders, due to the disappearance of J‐aggregates, while H‐aggregates were maintained. The study shows that the TEG‐PDI is a powerful SSDU to promote 2D or 1D self‐assembly of polymers depending on DPn through simple dissolution in water.

show abstract

Spontaneous Formation of Polymeric Nanoribbons in Water Driven by π–π Interactions

Berruée,

Guigner,

Bizien

et al. 2024

Angew Chem Int Ed

0

View full text Add to dashboard Cite

A simple method was developed to produce polymeric nanoribbons and other nanostructures in water. This approach incorporates a perylene diimide (PDI) functionalized by hydrophilic triethylene glycol (TEG) as a hydrophobic supramolecular structure directing unit (SSDU) into the core of hydrophilic poly(N,N‐dimethylacrylamide) (PDMAc) chains using RAFT polymerization. All PDI‐functional polymers dissolved spontaneously in water, forming different nanostructures depending on the degree of polymerization (DPn): nanoribbons and nanocylinders for DPn = 14 and 22, and spheres for DPn > 50 as determined by cryo‐TEM and SAXS analyses. UV‐VIS absorption spectroscopy was used to monitor the evolution of the PDI absorption signal upon dissolution. In solid form, all polymers show a H‐aggregate absorption signature, but upon dissolution in water, the shortest DPn forming nanoribbons evolved to show HJ‐aggregate absorption signals. Over time, the J‐aggregate band increased in intensity, while cryo‐TEM monitoring evidenced an increase in the nanoribbon’s width. Heating the nanoribbons above 60 °C, triggered a morphological transition from nanoribbons to nanocylinders, due to the disappearance of J‐aggregates, while H‐aggregates were maintained. The study shows that the TEG‐PDI is a powerful SSDU to promote 2D or 1D self‐assembly of polymers depending on DPn through simple dissolution in water.

show abstract

Tuning of Morphology by Chirality in Self‐Assembled Structures of Bis(Urea) Amphiphiles in Water

Cited by 3 publications

References 69 publications

Urea-Modified Self-Assembling Peptide Amphiphiles That Form Well-Defined Nanostructures and Hydrogels for Biomedical Applications

Urea-Modified Self-Assembling Peptide Amphiphiles That Form Well-Defined Nanostructures and Hydrogels for Biomedical Applications

Spontaneous Formation of Polymeric Nanoribbons in Water Driven by π–π Interactions

Spontaneous Formation of Polymeric Nanoribbons in Water Driven by π–π Interactions

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