Physics of engineered protein hydrogels

Abstract

Artificially engineered proteins and synthetic polypeptides have attracted widespread interest as building blocks for polymer hydrogels. The biophysical properties of the proteins, such as molecular recognition abilities, folded chain structures, and sequence-dependent thermodynamic behavior, enable advances in functional, responsive, and tunable gels. This review discusses the design of polymer hydrogels that incorporate protein domains, highlighting new challenges in polymer physics that are presented by this emerging class of materials. Five types of engineered protein hydrogels are discussed: (a) physically associating protein polymer gels, (b) amorphous artificially engineered protein networks, (c) engineered proteins with crystalline domains, (d) stretchable protein tertiary structures in gels, and (e) protein gels with biological recognition properties. The physics of the protein component and the physical properties of the resulting hydrogels are summarized, illustrating how advances in understanding these systems are leading to exciting novel biofunctional hydrogels.

Advances in smart materials: Stimuli‐responsive hydrogel thin films

“…For polyelectrolyte gels, eqs and are equivalent expressions for anionic and cationic hydrogels prepared in the presence of a solvent. Artificially engineered protein‐based hydrogels present a challenge in polymer physics; however, work by Kim et al reviews some of the progress on the physics of the dynamic intermolecular interactions of protein hydrogels …”

“…Artificially engineered protein-based hydrogels present a challenge in polymer physics; however, work by Kim et al reviews some of the progress on the physics of the dynamic intermolecular interactions of protein hydrogels. 25 Dynamic Swelling of Hydrogels The theories described above address the equilibrium swelling state of hydrogels; however, an understanding of the swelling dynamics through volume phase transitions may be useful for predicting the behavior of the hydrogel with time. There are many various models that simulate volume transitions, some of which have been recently reviewed.…”

Hydrogels That Actuate Selectively in Response to Organophosphates

“…[2][3][4][5][6][7][8] Among the OP hydrogels, taking advantage of the decomposition products released by nerve agents after reaction with oximes and the subsequent reaction with cross-linkers. [45][46][47][48] Recently, N,N-bis(acryloyl cystamine) (BAC) was used as the bridging molecule in radical polymerization, enabling numerous applications that are triggered by external stimuli such as pH, temperature, ionic strength, light, stress, and ligand binding (ligand-triggered actuators/sensors) to modulate the state of the disulfide bond. Many types of hydrogels have been engineered as building blocks for different stimuli-responsive materials due to their biocompatibility, biodegradability, tunability in mechanical properties, and molecular recognition abilities.…”

“…Many types of hydrogels have been engineered as building blocks for different stimuli-responsive materials due to their biocompatibility, biodegradability, tunability in mechanical properties, and molecular recognition abilities. [45][46][47][48] Recently, N,N-bis(acryloyl cystamine) (BAC) was used as the bridging molecule in radical polymerization, enabling numerous applications that are triggered by external stimuli such as pH, temperature, ionic strength, light, stress, and ligand binding (ligand-triggered actuators/sensors) to modulate the state of the disulfide bond. [49][50][51][52][53] Herein, the ability to couple oxime-based decontamination and disulfide chemistry is demonstrated, producing hydrogels that can decontaminate organophosphate compounds, sense the decontamination product, and transduce this sensing response into actuation of the gel which could be used to close pores in a gel layer or on a fabric coating.…”

Controlling topological entanglement in engineered protein hydrogels with a variety of thiol coupling chemistries

“…As this method only modifies the amino acid residues participating in junction formation, the protein strands can retain most of their function (e.g., elasticity and stimuli responsivity). In addition, many mechanical properties at equilibrium, such as modulus and maximum swelling ratio, can be controlled by varying the dosage of the crosslinking agents according to well-known laws of hydrogel physics and network theories (Graessley, 2004; Tanaka, 2011; Kim et al, 2013). In a typical crosslinking reaction, however, the formation of network imperfections, such as dangling chains and inelastic loops, is usually uncontrollable and difficult to quantify (Zhou et al, 2012).…”