Background

Hydrogels are materials typically composed of more than 90% (w/w) of water. Peptides can self-assemble into hydrogels, representing a promising class of soft biomaterials. The process of peptide self organization occurs at a molecular level in a ‘bottom-up’ approach where the simplest biomolecules, such as peptides or amino acids, interact with each other in aqueous solutions in a coordinated manner. In this process, one-dimensional peptide aggregates evolve to form fibrils that coil into larger fibers, crosslinking to form a gel. One of hydrogels weakness is the low stability in non-aqueous environments. When exposed to air, for example at ambient room conditions, hydrogels rapidly lose moisture, shrink and turn brittle due to water evaporation. On the other hand, to turn hydrogels into conductive materials there is usually the need to incorporate dopants in the hydrogel formulation.

As opposed to hydrogels, where water represents more than 90% (w/w) of the final gel formulation, in ionogels, the water content is greatly reduced as ionic liquids totally or partially replace water.

Technology Overview

It relates to a peptide ionogel composition (or formulation) wherein unprotected tripeptides are used as gelators. The tripeptide ionogels result from the gelation of ionic liquids with unprotected tripeptides that present self-assembly propensity.

Protected peptides with self-assembly propensity are those chemically modified with functional moieties at one or more different sites, namely the C-terminus, the N-terminus or at the amino acid side chains. The protecting groups used for the modification have self-assembling properties usually due to the hydrophobicity and aromaticity and include the 9-fluorenylmethyloxycarbonyl (Fmoc) group, or any groups containing aromatic tails, naphtyls, lipids, fatty acids, cyclic compounds, sugars, carbamide, or aliphatic tail-moieties. Unprotected peptides are those that are not modified at the C-terminus, N-terminus or side chains with protecting groups presenting self-assembling propensity, as listed above.

These tripeptide ionogels are supramolecular peptide assemblies in ionic liquids. They are stable at ambient conditions, have thermal, electrochemical and chemical stability in a wide range of temperature and humidity conditions, are conducting, soft, self-healing, thermoreversible, have a large electrochemical window, are non-flammable, nontoxic, biocompatible and biodegradable materials. These materials can further encapsulate other stimuli-responsive elements, as for example optical probes made of liquid crystals, including liquid crystals presenting nematic, smectic or chiral phases.

Stage of Development

Technology Readiness Level (TRL): 3

Benefits

The major advantages and unique properties of the formulations and production methods of tripeptide ionogels described in the present disclosure are:

Easy production of tripeptides, without the need to protect the tripeptide or to chemically modify the tripeptide with functional groups yielding self-assembling properties, as observed in all previous examples of small-peptide based low-molecular weight ionogelators;
Ionic liquids are designer solvents, being possible to tune the ionic liquid to the tripeptide of interest;
Chemical diversity and functionality of tripeptide ionogels is greater than in tripeptide hydrogels. In hydrogels, chemical functionality arises solely from the tripeptide sequence, whereas in ionogels both components (tripeptide and ionic liquid) confer chemical and functional richness to the system.

Applications

The tripeptide ionogels may find applications in a vast variety of technological fields, such as sensing devices; electronic devices; opto-electronic devices; flexible and wearable devices; conducting devices; materials for additive manufacturing; chemocatalysis and biocatalysis; coating materials; metal recovery; encapsulation, drug delivery and/or cell assays; pharmaceutical formulations and electrochemical devices.

Peptide Ionogel Composition, Methods and Uses Thereof

Patents

IP Status