Stimuli‐responsive poly(hydroxyethyl methacrylate) hydrogels from carboxylic acid‐functionalized crosslinkers

Abstract

Tailoring hydrogel properties by modifications of the crosslinker structure is a good method for the design of hydrogels with a wide range of properties. In this study, two novel carboxylic acid‐functionalized dimethacrylate crosslinkers (1a and 2a) are synthesized by the reaction of poly(ethylene glycol) or 2‐hydroxyethyl disulfide with tert‐butyl α‐bromomethacrylate followed by cleavage of tert‐butyl groups using trifluoroacetic acid. Their copolymerization reactivity with 2‐hydroxyethyl methacrylate (HEMA) investigated by photopolymerization studies performed on photo‐differential scanning calorimetry shows higher reactivity of 2a compared to 1a. These crosslinkers are then used at different ratios for fabrication of pH‐ and redox‐responsive poly(2‐hydroxyethyl methacrylate)‐based hydrogels. The swelling behavior of the hydrogels is found to be dependent on the structure of the crosslinker, degree of crosslinking, pH, and CaCl2 concentration. The redox‐responsive behavior is demonstrated by degradation of the hydrogel upon exposure to 1,4‐dithiothreitol. The dye Rhodamine 6G and the drug resorcinol are used as models to demonstrate the pH and redox dependent release of loaded compounds from the hydrogels. The electrostatic interactions between the carboxylate groups and the positively charged R6G are found to govern the release profile in DTT and counteract the diffusion of dye molecules and significant amount of release (79% in 120 hr) occurs only at highly acidic conditions. The degradation mediated release in DTT is observed better in case of resorcinol (around 88% in 5 hr). Overall, these hydrogels can be regarded as good candidates for several applications, such as matrices for controlled release, tissue repair, and regeneration.

Exploration of sea anemone-inspired high-performance biomaterials with enhanced antioxidant activity

“…The disulfide bonds of proteins are affected by the redox environment, implying that biomaterials can be used for targeted drug release [ 48 ]. The TSRL-based hydrogels were incubated in PBS containing either H 2 O 2 or DTT to investigate the potential redox-responsiveness.…”

pH-Responsive Super-Porous Hybrid Hydrogels for Gastroretentive Controlled-Release Drug Delivery

“…The literature reveals an absence of data on the effect of a mixture of pectin and 2HEMA-based SPHHs on GrDD [ 17 ]. In this study, 2HEMA is used as a binder to enhance mechanical stability [ 18 ]. Furthermore, the eradication of the Helicobacter pylori ( H. pylori ) bacterium (the gastric mucous layer of the stomach) is specified for gastric ulcers.…”

Meso-2,3-dimercaptosuccinic Acid–Based Macromers for pH-Sensitive Degradable Hydrogels

“…In particular, pH-responsive hydrogels have become very popular and are highly studied, especially in the biomedical field, since the pH of inflamed or cancerous tissue is slightly different from that of healthy tissue. , An important subgroup of pH-responsive hydrogels is composed of anionic ones. Their tunable pH-dependent swelling behaviors make them excellent materials for use in drug delivery systems, while their heavy metal complexing ability makes them important for metal chelation studies. − Carboxylic acid containing hydrogels can be prepared from natural polymers such as chitosan, alginate, and hyaluronic acid or from synthetic polymers such as poly­(acrylic acid) or macromers with various methods. , …”