Oxidized Nanocarbons-Tripeptide Supramolecular Hydrogels: Shape Matters!

Abstract

Short peptide hydrogels are attractive biomaterials but typically suffer from limited mechanical properties. Inclusion of other nanomaterials can serve the dual purpose of hydrogel reinforcement and of conferring additional physicochemical properties ( e. g., self-healing, conductivity), as long as they do not hamper peptide self-assembly. In particular, nanocarbons are ideal candidates, and their physicochemical properties have demonstrated great potential in nanocarbon-polymer gel biomaterials for tissue engineering or drug delivery. Recently, increasing interest in supramolecular hydrogels drove research also on their enhancement with nanocarbons. However, little is known on the effect of nanocarbon morphology on the self-assembly of short peptides, which are among the most popular hydrogel building blocks. In this work, three different oxidized nanocarbons ( i. e., carbon nanotube or CNT as 1D material, graphene oxide sheet or GO as 2D material, and carbon nanohorn or CNH as 3D material) were evaluated for their effects on the self-assembly of the unprotected tripeptide Leu-Phe-Phe at physiological conditions. Supramolecular hydrogels were obtained in all cases, and viscoelastic properties were clearly affected by the nanocarbons, which increased stiffness and resistance to applied stress. Notably, self-healing behavior was observed only in the case of CNTs. Tripeptide-nanotube interaction was noted already in solution prior to self-assembly, with the tripeptide acting as a dispersing agent in phosphate buffer. Experimental and in silico investigation of the interaction between peptide and CNTs suggests that the latter acts as nucleation templates for self-assembly and reassembly. Overall, we provide useful insights for the future design of composite biomaterials with acquired properties.

Self‐Assembly of an Amino Acid Derivative into an Antimicrobial Hydrogel Biomaterial

“…The very same signals dominated both spectra, with the most dominant ones being at 1355 cm À1 (symmetric stretching of the nitro group), [24] and 1607 cm À1 (stretching of CÀCb ond of the aromatic ring). [25] The signal at 1003 cm À1 is also present in both spectra and it is assigned to the breathing mode of the aromatic ring, typically ad ominant peak in Ramans pectra of Phe derivatives. [25] The signala t1 113cm À1 is not present in the Phe Raman spectra, whereas it hasb een observed fort he 4-nitrobenzoyl moiety.…”

“…[25] The signal at 1003 cm À1 is also present in both spectra and it is assigned to the breathing mode of the aromatic ring, typically ad ominant peak in Ramans pectra of Phe derivatives. [25] The signala t1 113cm À1 is not present in the Phe Raman spectra, whereas it hasb een observed fort he 4-nitrobenzoyl moiety. [26] The signal at 884 cm À1 is absent in the spectra of 4-nitrobenzoyl chloride [26] and underivatized Phe yet presentsa sw eak signal in those of Phe-containing peptides, [25] and in amino acid N-benzoyl derivatives, [27] thus we infer it can be assigned to the amide NÀHb ending.…”

Embedding and Positioning of Two FeII4L4 Cages in Supramolecular Tripeptide Gels for Selective Chemical Segregation

“…This interaction between anions and fibrils was evidenced by broadening of the 19 FNMR signals corresponding to the TFA À in the gel, as compared to the solutions containing either 1 or 2 alone.No significant changes in the proportion of FA encapsulated in 2 were observed between 2&Gel and 2 in solution, as TFA À is not ac ompeting guest for 2. This interaction between anions and fibrils was evidenced by broadening of the 19 FNMR signals corresponding to the TFA À in the gel, as compared to the solutions containing either 1 or 2 alone.No significant changes in the proportion of FA encapsulated in 2 were observed between 2&Gel and 2 in solution, as TFA À is not ac ompeting guest for 2.…”

“…Abstract: An unreported d,l-tripeptide self-assembled into gels that embedded Fe II 4 L 4 metal-organic cages to form materials that were characterized by TEM, EDX, Raman spectroscopy, rheometry,U V/Vis and NMR spectroscopy, and circular dichroism. The cage type and concentration modulated gel viscoelasticity,and thus the diffusion rate of molecular guests through the nanostructured matrix, as gauged by 19 Fand 1 HNMR spectroscopy. When two different cages were added to spatially separated gel layers,t he gel-cage composite material enabled the spatial segregation of am ixture of guests that diffused into the gel.…”

“…After the three-layered gel formation, am ixture of tetrabutylammonium ReO 4 À and FA in CD 3 CN was added on top of the gel, and the diffusion of the guests through the different gel layers was followed by slice-selective 19 FNMR spectroscopy (Figure 4c). Owing to the faster diffusion and uptake of FA in 2&Gel relative to that of ReO 4 À in 1&Gel, maximum guest encapsulation was achieved in 12 hf or the former, and in 62 hf or the latter (Figure 4c).…”