Micellized α‑Cyclodextrin-Based Supramolecular Hydrogel Exhibiting pH-Responsive Sustained Release and Corresponding Oscillatory Shear Behavior Analysis

The fabrication of supramolecular hydrogels from micellized PLLA/DMAEMA/PEGMA polymers with α-CD has been explored to design injectable gel formulations for sustained drug release. The tricomponent hydrogels (5% w/v)/α-CD (10% w/v) were able to sustain protein (BSA and lysozyme) release for 60–120 h at different pH conditions (pH 3, 7 and 10). In-depth rheological analysis highlighted the role of pH in tuning hydrogel behavior upon shear at microscopic level affecting protein release profiles. Protein release involved complex interactions within the network (isoelectric point and diffusion coefficient of the protein, p<i>K</i>_a of DMAEMA, and pore size of the hydrogel). Lissajous–Bowditch curves explained the microstructural response to increasing strain which weakened the supramolecular association and collapsed the formation of the porous hydrogel. Power Law was adopted to represent both transport mechanism and drug release phenomena. The release mechanism resulted from a combination of erosion- and diffusion-controlled release (non-Fickian and super case II)

Development of Lignin Supramolecular Hydrogels with Mechanically Responsive and Self-Healing Properties

The development of functional polymers from renewable lignin is attractive due to the depletion of fossil fuel and increasing environmental usage. A series of poly­(ethylene glycol) methyl ether methacrylate (PEGMA)-grafted lignin hyperbranched copolymers were prepared by atom transfer radical polymerization (ATRP). The chemical structures, molecular characteristic and thermal properties of these copolymers were evaluated and such copolymers were prepared in a range of molecular weights from 38.7 to 65.0 kDa by adjusting the PEGMA-to-lignin weight ratio. As a result from their hyperbranch architecture, their aqueous solutions were found to form supramolecular hydrogels with a very low critical gelation concentration of 1 wt % copolymers, in the presence of α-cyclodextrin (α-CD). The rheological properties of the supramolecular assemblies were investigated and these hydrogel systems showed tunable mechanical response and excellent self-healing capability. Combined with good biocompatibility, these new types of green supramolecular hydrogels based on lignin–PEGMA/cyclodextrin inclusion are potentially useful as a smart biomaterial for biomedical application