Tuning the associative properties and micelles geometry by stepwise quaternization of PDMAEMA

Self-healing injectable hydrogels incorporating hyaluronic acid and phytic acid: Rheological insights and implications for regenerative medicine

Eying the increasing impact of hyaluronic acid (HA) and its multifaceted applications, this study employs a non-toxic, one-pot strategy to develop injectable, self-healing hydrogels for biomedical applications. Phytic acid (PA), a plant-derived organic acid with high biocompatibility and numerous hydroxyl groups, can act as a cross-linking agent to form hydrogen-bonded networks with the HA chains. The study examined the optimal mass ratio of HA to PA to achieve superior hydrogel performance. Fourier transform infrared spectroscopy, rheological studies, and thermal analysis confirmed the successful formation of the hydrogels, which exhibited injectability, rapid self-healing, malleability, and elasticity. The investigation of different compositions revealed a sensitive influence of PA on the self-assembly phenomena of HA during flow. SEM cross-section images of the freeze-dried gels revealed a porous surface in the form of an interconnected network of microchannels. In addition, the hydrogel exhibits good tissue adhesion properties and promotes cell proliferation in biocompatibility tests on human gingival fibroblasts. The significance of this study lies in the ability of the proposed materials to be injected, to conform to the complex 3D structure of host tissues as well as their ability to recover after damage, indicating significant potential as scaffolds for wound healing.

Evaluation of hyaluronic acid-polymacrolactone hydrogels with 3D printing capacity

The implementation of personalized patches, tailored to individual genetic profiles and containing specific amounts of bioactive substances, has the potential to produce a transformative impact within the medical sector. There are several methods of designing scaffolds in the context of personalized medicine, with three-dimensional (3D) printing emerging as a pivotal technique. This innovative approach can be used to construct a wide variety of pharmaceutical dosage forms, characterized by variations in shape, release profile, and drug combinations, allowing precise dose individualization and the incorporation of multiple therapeutic agents. To expand the potential and applicability of personalized medicine, particularly with regards to indomethacin (IND), a drug necessitating individualized dosing, this study proposes the development of new transdermal delivery systems for IND based on hyaluronic acid and a polylactone synthesized within our research group, namely poly(ethylene brasilate-co-squaric acid) (PEBSA). The obtained systems were characterized in terms of their swelling capacity, rheological behavior, and morphological characteristics that highlighted the formation of stable three-dimensional networks. To impart specific shape and geometry to the structures, multi-component systems based on PEBSA, HA, and methacrylate gelatin were obtained. The scaffolds were loaded with IND and subsequently 3D printed. The release capacity of IND and its dependence on the relative ratios of the components comprising the scaffold composition were highlighted. The cytocompatibility studies revealed the successful development of biocompatible and noncytotoxic systems.

Rheology as a Tool for Fine-Tuning the Properties of Printable Bioinspired Gels

Over the last decade, efforts have been oriented toward the development of suitable gels for 3D printing, with controlled morphology and shear-thinning behavior in well-defined conditions. As a multidisciplinary approach to the fabrication of complex biomaterials, 3D bioprinting combines cells and biocompatible materials, which are subsequently printed in specific shapes to generate 3D structures for regenerative medicine or tissue engineering. A major interest is devoted to the printing of biomimetic materials with structural fidelity after their fabrication. Among some requirements imposed for bioinks, such as biocompatibility, nontoxicity, and the possibility to be sterilized, the nondamaging processability represents a critical issue for the stability and functioning of the 3D constructs. The major challenges in the field of printable gels are to mimic at different length scales the structures existing in nature and to reproduce the functions of the biological systems. Thus, a careful investigation of the rheological characteristics allows a fine-tuning of the material properties that are manufactured for targeted applications. The fluid-like or solid-like behavior of materials in conditions similar to those encountered in additive manufacturing can be monitored through the viscoelastic parameters determined in different shear conditions. The network strength, shear-thinning, yield point, and thixotropy govern bioprintability. An assessment of these rheological features provides significant insights for the design and characterization of printable gels. This review focuses on the rheological properties of printable bioinspired gels as a survey of cutting-edge research toward developing printed materials for additive manufacturing.

Removal characteristics of two anionic dyes by a polyethylenimine/poly(N,N-dimethylaminoethyl methacrylate) gel

The highly efficient gel obtained via the copolymerization of polyethylenimine (PEI) and poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) was successfully applied for the removal of two anionic dyes (amaranth and sunset yellow) from their aqueous solutions. Moreover, the results of the adsorption experiments for sunset yellow and amaranth on the PEI/PDMAEMA gel demonstrate that the adsorption equilibrium both could be achieved within 1 h, and the maximum adsorption capacities were 757 mg g⁻¹ and 744 mg g⁻¹ under unoptimized conditions, respectively. Moreover, the PEI/PDMAEMA composite gel was found to be pH-sensitive and the addition of salts together with ionic strength were also explored for understanding the adsorption performance. In addition, it can be found from the studies of adsorption mechanism that it is mainly electrostatic adsorption; moreover, the separation process conforms to the Langmuir adsorption isotherm model and the pseudo second-order kinetic model, which is a spontaneous endothermic process. When the PEI/PDMAEMA gel was used in continuous flow column, it could handle large volumes of dye solution with very low concentrations due to its strong enrichment capacity. Finally, the desorption experiments show that the PEI/PDMAEMA gel is easier to regenerate and has a longer lifetime. Therefore, the high adsorption capacity and easy operation of adsorption for amaranth and sunset yellow on the PEI/PDMAEMA gel make it a potential application prospect for the practical removal of other kinds of similar pollutants.

The highly efficient gel obtained via the copolymerization of polyethylenimine and poly(N,N-dimethylaminoethyl methacrylate) was successfully applied to remove two anionic dyes (amaranth and sunset yellow) from their aqueous solutions.