In Situ Synthesis of a Supramolecular Hydrogelator at an Oil/Water Interface for Stabilization and Stimuli‐Induced Fusion of Microdroplets

Abstract

Supramolecular hydrogels are expected to have applications as novel soft materials in various fields owingt o their designable functional properties.Herein, we developed an in situ synthesis of supramolecular hydrogelators,w hich can trigger gelation of an aqueous solution without the need for temperature change.T his was achieved by mixing two precursors,w hichi nduced the synthesis of as upramolecular gelator and its instantaneous self-assembly into nanofibers.W e then performed the in situ synthesis of this supramolecular gelator at an oil/water interface to produce nanofibers that covered the surfaces of the oil droplets (nanofiber-stabilized oil droplets). External stimuli induced fusion of the droplets owing to disassembly of the gelator molecules.F inally,w ed emonstrated that this stimuli-induced droplet fusion triggered as ynthetic reaction within the droplets.T his means that the confined nanofiber-stabilized droplets can be utilized as stimuli-responsive microreactors.

Intracellular self-assembly of supramolecular gelators to selectively kill cells of interest

“…Yang et al employed the combination of intracellular enzyme (alkaline phosphatase) and intracellular glutathione to induce the intracellular self-assembly of LMWG molecules, resulting in the death of liver cancer cells. These studies provide a proof-of-concept that spatiotemporal molecular self-assembly can be programmed in the molecular structure of a LMWG [38], which sets a LMWG hydrogel apart from a polymer gel.…”

“…1). In the last two decades, the synthesis of functional hydrogels using elaborately designed LMWGs has been reported, which indicates their potential use in cell scaffold [16][17][18][19][20][21][22][23], drug carriers [24][25][26][27][28], antimicrobial materials [29][30][31][32], catalysts [33,34], media for organic/inorganic reactions [14, [35][36][37][38], biosensors [39][40][41][42][43][44], emulsifiers [38,45] and absorbents for pollutant removal from waste water [46,47]. The large number of the studies on LMWGs give clues for the rational design of a LMWG.…”

Short Oligopeptides for Biocompatible and Biodegradable Supramolecular Hydrogels

“…We observed nanofibrous networks of these hydrogels, similar to other low-molecular-weight hydrogelators. 23,[28][29][30]…”

“…[11][12][13] The noncovalent interactions between peptides can also be designed to be responsive to various external stimuli (heat, pH, light, ions, enzyme and small molecules), leading to stimuli-triggered hydrogelation and stimuli-triggered gel-sol transition. [22][23][24][25][26][27][28][29][30] There are many examples of short-peptide-based hydrogelators. 1,20,21 The shortest peptide hydrogelator composed of two amino acids, Ile-Phe, reported by Ventura et al, which formed a hydrogel (only for water) at 1.5 wt.% through the formation of nanofibers with a diameter of approximately 55 nm.…”

Hybrid Hydrogels from Nongelling Polymers Using a Fibrous Peptide Hydrogelator at Low Concentrations

“…Low-molecular-weight (LMW) gelators represent a promising class of soft materials in a wide range of applications. − The LMW gels are mainly constructed through noncovalent interactions including hydrogen bonding, hydrophobic, π–π stacking, van der Waals, and electrostatic interactions. − They have significant advantages owing to facile synthesis, diverse structures, tunable properties, and rapid response to external stimuli. ,− Particularly, peptide-based hydrogelators are intriguing biomaterials due to their excellent biocompatibility, low immunogenicity, and adaptable secondary conformations, which enable excellent candidates for drug delivery, tissue engineering, and wound healing. − The peptide hydrogelators generally form a fibrillar network structure through molecular self-assembly. ,− Numerous peptide hydrogelators have been constructed from oligopeptides, , Fmoc peptides, − peptide amphiphiles (PAs), − and cyclic dipeptides . However, merely a few LMW peptide hydrogelators have been reported to trigger the gelation of polymers, and the gelation concentration is generally high. − …”