Chemical reaction powered transient polymer hydrogels for controlled formation and free release of pharmaceutical crystals

Bai, Shengyu; Niu, Xiaofeng; Wang, Hucheng; Wei, Lai; Liu, Liqun; Liu, Xinyu; Eelkema, Rienk; Guo, Xuhong; Esch, Jan H. van; Wang, Yiming

doi:10.1016/j.cej.2021.128877

Cited by 23 publications

(31 citation statements)

References 29 publications

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“…This implies that larger proportions of acid groups and increased EDC concentrations result in more anhydride cross-links, causing the progressive increase in G′ max shown for all polymer hydrogels in Figure 3a. This aligns with the recent literature report 26 that increasing EDC fuel leads to cross-linking of more AA and therefore increased cross-link density.…”

Section: ■ Results and Discussionsupporting

confidence: 92%

“…This is consistent with transient covalent cross-linking of diacids using EDC via anhydride formation. 25,26 An eventual crossover between G′ and G″ was observed in all time sweep data indicating that G″ becomes dominant after the EDC fuel is consumed and the transient gels return to aqueous polymer solutions. The results indicate formation of temporary anhydride cross-links and 1-ethyl-3-(3-dimethylaminopropyl)urea (EDU) followed by eventual hydrolysis of anhydrides to the starting acids (Scheme 1b).…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…Recently, Wang and co-workers also reported similar out-ofequilibrium anhydride-cross-linked polymer hydrogels generated by EDC, which were used for the controlled formation and isolation of pharmaceutical crystals. 26 In their case, they copolymerized acrylic acid (AA) with N-isopropylacrylamide (NIPAm) to form poly(NIPAm-co-AA) as the hydrogel precursor. Structure−property effects in this study revealed that increased EDC fuel concentration increases the lifetime and viscoelasticity of polymer hydrogels.…”

Section: ■ Introductionmentioning

confidence: 99%

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Tailoring Lifetimes and Properties of Carbodiimide-Fueled Covalently Cross-linked Polymer Networks

et al. 2021

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The mechanical properties of nonequilibrium polymer hydrogels obtained from the transient cross-linking of polymer chains by a chemical fuel were investigated. Aqueous polymers featuring pendant carboxylic acids were treated with a carbodiimide to give anhydride-cross-linked gels. The anhydrides spontaneously hydrolyze back to the polymer solution, and the cycle can be repeated multiple times. Oscillatory rheology was employed to study the effects of temperature, fuel concentration, chain length, and polymer composition on the storage and loss moduli of the polymeric materials as well as the time taken for the polymers to undergo decross-linking. Regardless of the temperature used, at constant carbodiimide concentration, degelation times are more sensitive to experimental temperature than are the peak storage moduli. Decross-linking times decrease with increasing temperature. As carbodiimide concentration decreases, there is a decrease in moduli and decross-linking times. Within the scope of materials studied, the polymer structure was found to have a relatively small impact on the transient properties of gel networks compared to the fuel concentration and temperature. These findings facilitate the design of tunable on-demand networks and gels.

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Section: ■ Results and Discussionsupporting

confidence: 92%

Section: ■ Results and Discussionmentioning

confidence: 95%

Section: ■ Introductionmentioning

confidence: 99%

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Tailoring Lifetimes and Properties of Carbodiimide-Fueled Covalently Cross-linked Polymer Networks

et al. 2021

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“…A second deactivating reaction then restores the charge and triggers disassembly. This and related approaches have led to interesting new properties such as self-erasing inks [10][11][12] , timed drug release [13][14][15][16] , temporary 'artery clamping' 17,18 , and transient catalysis 19,20 . Still, we are currently in the Rube Goldberg era of artificial dissipative self-assembly: performing simple tasks, like assembly and disassembly, in overly complicated and inefficient ways.…”

Section: Inspiration From Naturementioning

confidence: 99%

Insights into chemically-fueled supramolecular polymers

Sharko

Livitz

Piccoli

et al. 2022

Preprint

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Supramolecular polymerization can be controlled in space and time by chemical fuels. A non-assembled monomer is activated by the fuel and subsequently self-assembles into a polymer. Deactivation of the molecule either in solution or inside the polymer leads to disassembly. Whereas biology has already mastered this approach, fully artificial examples have only appeared in the past decade. Here, we map the available literature examples into four distinct regimes depending on their activation/deactivation rates and the equivalents of deactivating fuel. We present increasingly complex mathematical models, first considering only the chemical activation/deactivation rates (i.e., Transient Activation), and later including the full details of the isodesmic or cooperative supramolecular processes (i.e., Transient Self-assembly). We finish by showing that sustained oscillations are possible in chemically fueled cooperative supramolecular polymerization and provide mechanistic insights. We hope our models encourage the exact quantification of activation, deactivation, assembly, and disassembly kinetics in future studies.

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“…1,[15][16][17] Carbodiimides, typically EDC ((N -(3-(dimethylamino)-propyl)-N -ethylcarbodiimide hydrochloride), stand out as versatile fuels. They have been used in recent reports by Boekhoven, [18][19][20] us, [21][22][23] Das, 24,25 and several other research groups [26][27][28] to generate nonequilibrium behavior. The associated chemistry is quite simple: carbodiimides react with aqueous carboxylic acids to generate carboxylic anhydrides that then undergo hydrolysis to regenerate the parent carboxylic acids.…”

Section: Introductionmentioning

confidence: 99%

Substituent Effects on Transient, Carbodiimide-Fueled Geometry Changes in Diphenic Acids

Jayalath¹,

Gerken²,

Mantel³

et al. 2021

Preprint

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Nucleotide-fueled conformational changes in motor proteins are key to many important cell functions. Inspired by this biological behavior, we report a simple chemical system that exhibits carbodiimide-fueled geometry changes. Bridging via transient anhydride formation leads to a significant reduction of the twist about the biaryl bond of substituted diphenic acids, giving a simple molecular clamp. The kinetics are well-described by a simple mechanism, allowing structure–property effects to be determined. The kinetic parameters can be used to derive important characteristics of the system such as the efficiencies (anhydride yields), maximum anhydride concentrations, and overall lifetimes. Transient diphenic anhydrides tolerate steric hindrance ortho to the biaryl bond but are significantly affected by electronic effects, with electron-deficient substituents giving lower yields, peak conversions, and lifetimes. The results provide useful guidelines for the design of functional systems incorporating diphenic acid units

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Chemical reaction powered transient polymer hydrogels for controlled formation and free release of pharmaceutical crystals

Cited by 23 publications

References 29 publications

Tailoring Lifetimes and Properties of Carbodiimide-Fueled Covalently Cross-linked Polymer Networks

Tailoring Lifetimes and Properties of Carbodiimide-Fueled Covalently Cross-linked Polymer Networks

Insights into chemically-fueled supramolecular polymers

Substituent Effects on Transient, Carbodiimide-Fueled Geometry Changes in Diphenic Acids

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