Stimuli-Responsive DNA-Based Hydrogels on Surfaces for Switchable Bioelectrocatalysis and Controlled Release of Loads

Abstract

The assembly of enzyme [glucose oxidase (GOx)]-loaded stimuli-responsive DNA-based hydrogels on electrode surfaces, and the triggered control over the stiffness of the hydrogels, provides a means to switch the bioelectrocatalytic functions of the hydrogels. One system includes the assembly of GOx-loaded, pH-responsive, hydrogel matrices cross-linked by two cooperative nucleic acid motives comprising permanent duplex nucleic acids and “caged” i-motif pH-responsive duplexes. Bioelectrocatalyzed oxidation of glucose leads to the formation of gluconic acid that acidifies the hydrogel resulting in the separation of the i-motif constituents and lowering the hydrogel stiffness. Loading of the hydrogel matrices with insulin results in the potential-triggered, glucose concentration-controlled, switchable release of insulin from the hydrogel-modified electrodes. The switchable bioelectrocatalyzed release of insulin is demonstrated in the presence of ferrocenemethanol as a diffusional electron mediator or by applying an electrically wired integrated matrix that includes ferrocenyl-modified GOx embedded in the hydrogel. The second GOx-loaded, stimuli-responsive, DNA-based hydrogel matrix associated with the electrode includes a polyacrylamide hydrogel cooperatively cross-linked by duplex nucleic acids and “caged” G-quadruplex-responsive duplexes. The hydrogel matrix undergoes K+-ions/crown ether-triggered stiffness changes by the cyclic K+-ion-stimulated formation of G-quadruplexes (lower stiffness) and the crown ether-induced separation of the G-quadruplexes (higher stiffness). The hydrogel matrices demonstrate switchable bioelectrocatalytic functions guided by the stiffness properties of the hydrogels.

Electrically Powered Dissipative Hydrogel Networks Reveal Transient Stiffness Properties for Out-of-Equilibrium Operations

“…By controlling polymer–solvent interactions through the formation of temporary cationic charges on a polymer backbone, Eelkema and co-workers have developed a strategy to program hydrogel swelling without affecting the net cross-linking density of the bulk network . On the other hand, hydrogels, as membranes or coatings of devices interfaced with biological systems, play a central role in a wide range of biomedical applications. , Considerable effort has been devoted to the development of hydrogel films that employ light, temperature, chemical agents, , or electricity as stimuli to trigger hydrogel networks and switch their stiffness properties between two equilibrium states. Among stiffness-switching hydrogels, those utilizing redox-responsive cross-linkers based on supramolecular complexes, such as ferrocene/cyclodextrin host–guest complexes, , exhibit rapid expansion/contraction transitions and can be precisely controlled electrochemically, resulting in high spatiotemporal resolution and essentially no chemical waste.…”

Chemical and Photochemical-Driven Dissipative Fe3+/Fe2+-Ion Cross-Linked Carboxymethyl Cellulose Gels Operating Under Aerobic Conditions: Applications for Transient Controlled Release and Mechanical Actuation

“…Moreover, the redox-active dissipative cryogel was coupled to a photosensitized electron transfer process reducing the redox sites, allowing the light-induced control of transient stiffness properties of the cryogel and the subsequent light-regulated temporal release of the loads. It should be noted that while redox-triggered switchable stiffness-controlled hydrogels were reported (chemical agents or electrochemical signals), dissipative redox-active gels are scarce, and particularly, emerging functions of the dissipative matrices are unprecedented.…”

Dual endogenous stimulus-responsive Fe3O4@enzymes@ZIF-8 nanocomposites promote enzymatic circulation chemotherapy

“…Stimulus-responsive technology has been extensively used to fabricate different types of novel nanocomposites, e.g., inorganic nanoparticles, 1,2 hydrogels, 3,4 and biomacromolecules, 5,6 which could perform structural alteration in response to environmental triggers to achieve a wide range of applications in nanofabrication, 7 biosensing, 8 bioimaging, 9 biocatalysis, etc. 10,11 Recently, stimulus-responsive nanocomposites have been applied for cancer therapy, which can be divided into exogenous and endogenous stimulus-responsive therapy. As far as exogenous therapy is concerned, it originates from exogenous stimuli, e.g., magnetic field, 12 ultrasound, 13 light, 14 and microwaves, 15 resulting in the administration of cancer cell therapy via exogenous stimulus-responsive materials.…”

“…, inorganic nanoparticles, 1,2 hydrogels, 3,4 and biomacromolecules, 5,6 which could perform structural alteration in response to environmental triggers to achieve a wide range of applications in nanofabrication, 7 biosensing, 8 bioimaging, 9 biocatalysis, etc. 10,11 Recently, stimulus-responsive nanocomposites have been applied for cancer therapy, which can be divided into exogenous and endogenous stimulus-responsive therapy. As far as exogenous therapy is concerned, it originates from exogenous stimuli, e.g.…”