Minimalistic and uncapped d,l-peptides self-assemble into bioadhesive hydrogels that successfully mimic the extracellular matrix and lead to high cell viability.

N-(4-Nitrobenzoyl)-Phe self-assembled into at ransparent supramolecular hydrogel, whichd isplayed high fibroblast and keratinocyte cell viability.T he compound showed am ild antimicrobial activity against E. coli both as ah ydrogel and in solution.S ingle-crystal XRD data revealed packing details,i ncluding protonation of the C-terminus due to an apparent pK a shift, as confirmed by pH titrations. MicroRaman analysisr evealed almosti denticalf eaturesb etween the gel and crystal states,a lthough more disorder in the former. The hydrogel is thermoreversible and disassemblesw ithin a range of temperaturest hat can be fine-tunedb ye xperimental conditions, such as gelator concentration. At the minimum gellingc oncentration of 0.63 wt %, the hydrogel disassembles in ap hysiological temperature range of 39-42 8C, thus opening the way to its potential use as ab iomaterial.[a] Dr.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Minimalistic peptides composed of d- and l-amino acids are attractive building blocks for functional supramolecular materials, including catalysts. d-Amino acids have long been known to promote turn conformations in peptides, yet unexpected twists continue to emerge on their effects on self-assembly. The combination of single-crystal X-ray diffraction and full-atom molecular dynamics have finally unraveled fine details of how l-d-l-tripeptides visit different conformations in solution and establish key interactions in supramolecular structures.

The combination of different components such as carbon nanostructures and organic gelators into composite nanostructured hydrogels is attracting wide interest for a variety of applications, including sensing and biomaterials. In particular, both supramolecular hydrogels that are formed from unprotected D,L-tripeptides bearing the Phe-Phe motif and nitrogen-doped carbon nanodots (NCNDs) are promising materials for biological use. In this work, they were combined to obtain luminescent, supramolecular hydrogels at physiological conditions. The self-assembly of a tripeptide upon application of a pH trigger was studied in the presence of NCNDs to evaluate effects at the supramolecular level. Luminescent hydrogels were obtained whereby NCND addition allowed the rheological properties to be fine-tuned and led to an overall more homogeneous system composed of thinner fibrils with narrower diameter distribution.

The use of peptides to template inorganic nanoparticle formation has attracted great interest as a green route to advance structures with innovative physicochemical properties for a variety of applications that range from biomedicine and sensing, to catalysis. In particular, short-peptide gelators offer the advantage of providing dynamic supramolecular environments for the templating effect on the formation of inorganic nanoparticles directly in the resulting gels, and ideally without using further reductants or chemical reagents. This mini-review describes the recent progress in the field to outline future research directions towards dynamic functional materials that exploit the synergy between supramolecular chemistry, nanoscience, and the interface between organic and inorganic components for advanced performance.

The family of carbon nanostructures comprises several members, such as fullerenes, nano-onions, nanodots, nanodiamonds, nanohorns, nanotubes, and graphene-based materials. Their unique electronic properties have attracted great interest for their highly innovative potential in nanomedicine. However, their hydrophobic nature often requires organic solvents for their dispersibility and processing. In this review, we describe the green approaches that have been developed to produce and functionalize carbon nanomaterials for biomedical applications, with a special focus on the very latest reports.

Self-assembling peptides are attracting wide interest as biodegradable building blocks to achieve functional nanomaterials that do not persist in the environment. Amongst the many applications, biocatalysis is gaining momentum, although a clear structure-to-activity relationship is still lacking. This work applied emerging design rules to the heterochiral octapeptide sequence His–Leu–DLeu–Ile–His–Leu–DLeu–Ile for self-assembly into nanofibrils that, at higher concentration, give rise to a supramolecular hydrogel for the mimicry of esterase-like activity. The peptide was synthesized by solid-phase and purified by HPLC, while its identity was confirmed by 1H-NMR and electrospray ionization (ESI)-MS. The hydrogel formed by this peptide was studied with oscillatory rheometry, and the supramolecular behavior of the peptide was investigated with transmission electron microscopy (TEM) analysis, circular dichroism (CD) spectroscopy, thioflavin T amyloid fluorescence assay, and attenuated total reflectance (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The biocatalytic activity was studied by monitoring the hydrolysis of p-nitrophenyl acetate (pNPA) at neutral pH, and the reaction kinetics followed an apparent Michaelis–Menten model, for which a Lineweaver–Burk plot was produced to determine its enzymatic parameters for a comparison with the literature. Finally, LC–MS analysis was conducted on a series of experiments to evaluate the extent of, if any, undesired peptide acetylation at the N-terminus. In conclusion, we provide new insights that allow gaining a clearer picture of self-assembling peptide design rules for biocatalysis.

Nanostructured gels have emerged as an attractive functional material to innovate the field of energy, with applications ranging from extraction and purification to nanocatalysts with unprecedented performance. In this review we discuss the various classes of nanostructured gels and the most recent advancements in the field with a perspective on future directions of this challenging area.