Hofmeister effects of anions on self-assembled thermogels

Loh, Wei Wei; Lin, Qunying; Lim, Chen Chuan; Guo, Liangfeng; Tang, Karen Yuanting; Loh, Xian Jun; Lim, Jason Y. C.

doi:10.1016/j.mtchem.2021.100674

Cited by 17 publications

(13 citation statements)

References 75 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, the gel without Ca 2+ has a ω c of ∼0.3 Hz at 37 °C, suggesting faster dissociation kinetics and relaxation process [25c] . However, while the T gel of uncharged polymer thermogels decreased linearly with increasing Cl − concentration, [21a] that of polyanionic EPCT showed a smaller extent of decrease with higher CaCl 2 content (Figure 3B). This may suggest that unlike uncharged amphiphilic polymers which interact minimally with cations, [21a,d] Ca 2+ is binding to accessible pendant carboxylate groups of EPCT, which get increasingly saturated at high CaCl 2 concentrations.…”

Section: Resultsmentioning

confidence: 96%

“…However, while the T gel of uncharged polymer thermogels decreased linearly with increasing Cl − concentration, [21a] that of polyanionic EPCT showed a smaller extent of decrease with higher CaCl 2 content (Figure 3B). This may suggest that unlike uncharged amphiphilic polymers which interact minimally with cations, [21a,d] Ca 2+ is binding to accessible pendant carboxylate groups of EPCT, which get increasingly saturated at high CaCl 2 concentrations. Being strongly solvated, [26] Ca 2+ increases the hydration and water solubility of EPCT polymers, counteracting the effects of Cl − .…”

Section: Resultsmentioning

confidence: 97%

“…As shown in Table 1, the presence of metal salts causes significant changes to the T gel , storage moduli (G’) and viscosity of the EPCT thermogels. While chloride is known to affect the self‐assembly of amphiphilic polymers by interfering with their hydration, [21] we have previously shown that different kosmotropic and chaotropic cations exert only minimal influences on the gel stiffness of uncharged polyurethane PEG‐PPG‐PCL thermogels (G’ values) [21a] . This also ruled out the possibility of significant polyether‐cation ion‐dipole interactions, [22] akin to those of crown ether‐cation complexes, playing a role in modulating gel stiffness.…”

Section: Resultsmentioning

confidence: 99%

“…A comparison of the average micelle sizes determined by dynamic light scattering in 0.5 M salt solutions revealed that generally, the presence of monovalent cations result in slightly larger micelles than that of divalent cations (Figure 4A). While kosmotropic chloride anions tend to cause enhanced amphiphilic polymer aggregation to form larger micelles due to the salting‐out effect, [21a] the less effective charge‐shielding from monovalent cations (seen from zeta potential measurements in Table 1) likely results in greater inter‐micelle electrostatic repulsion that causes the EPCT unimers to pack together less tightly to form looser and larger aggregates.…”

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

A Polyanionic Tartrate‐containing Temperature‐responsive Hydrogel

Loh

Miao

Goh

et al. 2022

Chemistry An Asian Journal

Self Cite

View full text Add to dashboard Cite

Thermogels, a class of hydrogels which show spontaneous sol‐gel phase transition when warmed, are an important class of soft biomaterials. To date, however, most amphiphilic polymers that are able to form thermogels in aqueous solution are uncharged, and the influence of ionisable groups on thermogelation are largely unknown. Herein, we report the first example of a polyanionic amphiphilic multi‐block copolymer, containing multiple pendant carboxylate groups, that can form transparent thermogels spontaneously when warmed up to physiological temperature. We demonstrate that introducing negative charges onto thermogelling polymers could significantly alter the properties of the micelles and thermogels formed. Furthermore, the polymer's polyanionic character provides new options for modulating the gel rheological properties, such as stiffness and gelation temperatures, through electrostatic interactions with different cations. We also demonstrated that the polyanionic thermogel allowed slower sustained release of a cationic model drug compound compared to an anionic one over 2 weeks. The findings from our study demonstrate exciting new possibilities for advanced biomedical applications using charged polyelectrolyte thermogel materials.

show abstract

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

A Polyanionic Tartrate‐containing Temperature‐responsive Hydrogel

Loh

Miao

Goh

et al. 2022

Chemistry An Asian Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…There are also traces of rounded globular structures on the surface. Thicker walls have been previously observed in the presence of physiological concentration of salts such as sodium chloride, [57] so it is plausible that the changes seen is due to the interaction of the thermogel with vitreous fluids. Larger pores are also observed in EPT5-1 T gel at a lower concentration (Fig.…”

Section: Analysis Of Gels Harvested From Vitreousmentioning

confidence: 90%

Injectable PTHF-based thermogelling polyurethane implants for long-term intraocular application

et al. 2022

View full text Add to dashboard Cite

Background Hydrogels show great potential to be used for intraocular applications due to their high-water content and similarity to the native vitreous. Injectable thermosensitive hydrogels through a small-bore needle can be used as a delivery system for drugs or a tamponading substitute to treat posterior eye diseases with clear clinical potential. However, none of the currently available thermosensitive hydrogels can provide intraocular support for up to 3 months or more. Method In this study, an injectable polytetrahydrofuran (PTHF)-based thermosensitive hydrogel was synthesized by polyurethane reaction. We examined the injectability, rheological properties, microstructure, cytotoxicity, and in vivo compatibility and stability of the hydrogels in rabbit eyes. Results We found that the PTHF block type and PTHF component ratio could modulate thermogelation properties of the polyurethane polymers. The PTHF-based hydrogel implants retained normal retinal structure and function. Incorporating bioinert PTHF generated highly biocompatible and more stable thermogels in the vitreous cavity, with gel networks and the presence of polymer still observed after 3 months when other thermogels would have been completely cleared. Moreover, despite lacking hydrolytically cleavable linkages, the polymers could be most naturally removed from the native vitreous by bio-erosion without additional surgical interventions. Conclusion Our findings suggest the potential of incorporating hydrophobic bioinert blocks to enhance the in vivo stability of supramolecularly associated hydrogels for long-term intraocular applications. Graphical Abstract

show abstract

Stimuli‐Responsive Peptide Self‐Assembly to Construct Hydrogels with Actuation and Shape Memory Behaviors

Xiang

Liu

et al. 2023

Adv Funct Materials

View full text Add to dashboard Cite

Hydrogel actuators, capable of generating reversible deformation in response to external stimulus, are widely considered as new emerging intelligent materials for applications in soft robots, smart sensors, artificial muscles, and so on. Peptide self‐assembly is widely applied in the construction of intelligent hydrogel materials due to their excellent stimulus response. However, hydrogel actuators based on peptide self‐assembly are rarely reported and explored. In this study, a pH‐responsive peptide (MA‐FIID) is designed and introduced into a poly(N‐isopropyl acrylamide) backbone (PNIPAM) to construct bilayer and heterogeneous hydrogel actuators based on the assembly and disassembly of peptide molecules under different pH conditions. These peptide‐containing hydrogel actuators can perform controllable bending, bucking, and complex deformation under pH stimulation. Meanwhile, the Hofmeister effect of PNIPAM hydrogels endows these peptide‐containing hydrogels with enhanced mechanical strength, ionic stimulus response (CaCl2), and excellent shape‐memory property. This work broadens the application of supramolecular self‐assembly in the construction of intelligent hydrogels, and also provides new inspirations for peptide self‐assembly to construct smart materials.

show abstract

Hofmeister effects of anions on self-assembled thermogels

Cited by 17 publications

References 75 publications

A Polyanionic Tartrate‐containing Temperature‐responsive Hydrogel

A Polyanionic Tartrate‐containing Temperature‐responsive Hydrogel

Injectable PTHF-based thermogelling polyurethane implants for long-term intraocular application

Stimuli‐Responsive Peptide Self‐Assembly to Construct Hydrogels with Actuation and Shape Memory Behaviors

Contact Info

Product

Resources

About