Self‐Propelling Hybrid Gels Incorporating an Active Self‐Assembled, Low‐Molecular‐Weight Gelator

Abstract

Hybrid gel beads based on combining a low‐molecular‐weight gelator (LMWG) with a polymer gelator (PG) demonstrate an enhanced ability to self‐propel in water, with the LMWG playing an active role. Hybrid gel beads were loaded with ethanol and shown to move in water owing to the Marangoni effect changes in surface tension caused by the expulsion of ethanol – smaller beads move farther and faster than larger beads. Flat shapes of the hybrid gel were cut using a “stamp” – circles moved the furthest, whereas stars showed more rotation on their own axes. Comparing hybrid LMWG/PG gel beads with PG‐only beads demonstrated that the LMWG speeds up the beads, enhancing the rate of self‐propulsion. Self‐assembly of the LMWG into a “solid‐like” network prevents its leaching from the gel. The LMWG also retains its own unique function – specifically, remediating methylene blue pollutant dye from basic water as a result of noncovalent interactions. The mobile hybrid beads accumulate this dye more effectively than PG‐only beads. Self‐propelling gel beads have potential applications in removal/delivery of active agents in environmental or biological settings. The ability of self‐assembling LMWGs to enhance mobility and control removal/delivery suggests that adding them to self‐propelling systems can add significant value.

Mechanically Robust Hybrid Gel Beads Loaded with “Naked” Palladium Nanoparticles as Efficient, Reusable, and Sustainable Catalysts for the Suzuki–Miyaura Reaction

“…The characterization of the gel beads in this work is consistent with our previous report, which made use of this type of bead in a different context . The formulation employed 0.3% wt/vol of the DBS-CONHNH 2 LMWG and 1.0% wt/vol of the agarose PG.…”

“…Hybrid PG/LMWG gel systems open the possibility of imposing shape/morphology on gels, such as beads. , For the work in this paper, we envisioned that the use of agarose as a PG, and employing a higher concentration compared to our previous gel blocks, might facilitate the formation of well-defined beads and prevent the mechanical degradation caused by stirring without compromising the activity of our catalyst. Using catalyst-loaded beads allows for facile precise dosing of Pd compared to using gel blocks since each bead contains a discrete, known amount of Pd.…”

Combining gellan gum with a functional low-molecular-weight gelator to assemble stiff shaped hybrid hydrogels for stem cell growth

“…Initially DBS-CONHNH 2 /GG gel beads were prepared by the emulsion method previously described by us, 14 with CaCl 2 being used for crosslinking (Fig. 1).…”

“…1). 14 We have demonstrated that in such hybrid gels, the LMWGs provided functionality, whilst the alginate offered mechanical support and robustness to shape and structure the LMWGs into gel beads or tubes. On starting this work with gellan gum, we wanted to explore the potential use of this PG instead of calcium alginate to develop gels with enhanced properties.…”

Shaping and Patterning Supramolecular Materials─Stem Cell-Compatible Dual-Network Hybrid Gels Loaded with Silver Nanoparticles

“…In this regard, we recently explored multicomponent hybrid gels based on the LMWG 1,3:2:4-di­(4-acylhydrazide)-benzylidene sorbitol (DBS-CONHNH 2 ; Scheme ) and the polysaccharide calcium alginate (Scheme ). − DBS-CONHNH 2 is a thermally triggered LMWG that self-assembles in response to heat–cool cycles, giving biocompatible hydrogels that have been employed in a variety of ways including drug delivery, cell culture, and environmental remediation. − The biopolymer alginate forms hydrogels when cross-linked with bivalent cations (e.g., Ca 2+ from CaCl 2 ). − Combining the two gelators allowed us to impose a spherical shape on the LMWG while keeping its functionality, leading to a rare example of LMWG hydrogel beads. − ,− …”