Precise Design of Alginate Hydrogels Crosslinked with Microgels for Diabetic Wound Healing

Multifunctional and theranostic hydrogels for wound healing acceleration: An emphasis on diabetic-related chronic wounds

Hydrogels represent intricate three-dimensional polymeric structures, renowned for their compatibility with living systems and their ability to naturally degrade. These networks stand as promising and viable foundations for a range of biomedical uses. The practical feasibility of employing hydrogels in clinical trials has been well-demonstrated. Among the prevalent biomedical uses of hydrogels, a significant application arises in the context of wound healing. This intricate progression involves distinct phases of inflammation, proliferation, and remodeling, often triggered by trauma, skin injuries, and various diseases. Metabolic conditions like diabetes have the potential to give rise to persistent wounds, leading to delayed healing processes. This current review consolidates a collection of experiments focused on the utilization of hydrogels to expedite the recovery of wounds. Hydrogels have the capacity to improve the inflammatory conditions at the wound site, and they achieve this by diminishing levels of reactive oxygen species (ROS), thereby exhibiting antioxidant effects. Hydrogels have the potential to enhance the growth of fibroblasts and keratinocytes at the wound site. They also possess the capability to inhibit both Gram-positive and Gram-negative bacteria, effectively managing wounds infected by drug-resistant bacteria. Hydrogels can trigger angiogenesis and neovascularization processes, while also promoting the M2 polarization of macrophages, which in turn mitigates inflammation at the wound site. Intelligent and versatile hydrogels, encompassing features such as pH sensitivity, reactivity to reactive oxygen species (ROS), and responsiveness to light and temperature, have proven advantageous in expediting wound healing. Furthermore, hydrogels synthesized using environmentally friendly methods, characterized by high levels of biocompatibility and biodegradability, hold the potential for enhancing the wound healing process. Hydrogels can facilitate the controlled discharge of bioactive substances. More recently, there has been progress in the creation of conductive hydrogels, which, when subjected to electrical stimulation, contribute to the enhancement of wound healing. Diabetes mellitus, a metabolic disorder, leads to a slowdown in the wound healing process, often resulting in the formation of persistent wounds. Hydrogels have the capability to expedite the healing of diabetic wounds, facilitating the transition from the inflammatory phase to the proliferative stage. The current review sheds light on the biological functionalities of hydrogels, encompassing their role in modulating diverse mechanisms and cell types, including inflammation, oxidative stress, macrophages, and bacteriology. Additionally, this review emphasizes the significance of smart hydrogels with responsiveness to external stimuli, as well as conductive hydrogels for promoting wound healing. Lastly, the discussion delves into the advancement of environmentally friendly hydrogels with high biocompatibility, aimed at accelerating the wound healing process.

Double Network Physical Crosslinked Hydrogel for Healing Skin Wounds: New Formulation Based on Polysaccharides and Zn2

Developing convenient, efficient, and natural wound dressings remain the foremost strategy for treating skin wounds. Thus, we innovatively combined the semi-dissolved acidified sol-gel conversion method with the internal gelation method to fabricate SA (sodium alginate)/CS (chitosan)/Zn2+ physically cross-linked double network hydrogel and named it SA/CS/Zn2+ PDH. The characterization results demonstrated that increased Zn2+ content led to hydrogels with improved physical and chemical properties, such as rheology, water retention, and swelling capacity. Moreover, the hydrogels exhibited favorable antibacterial properties and biocompatibility. Notably, the establishment of an in vitro pro-healing wound model further confirmed that the hydrogel had a superior ability to repair wounds and promote skin regeneration. In future, as a natural biomaterial with antimicrobial properties, it has the potential to promote wound healing.

Alginate-Based Hydrogels and Scaffolds for Biomedical Applications

Alginate is a natural polymer of marine origin and, due to its exceptional properties, has great importance as an essential component for the preparation of hydrogels and scaffolds for biomedical applications. The design of biologically interactive hydrogels and scaffolds with advanced, expected and required properties are one of the key issues for successful outcomes in the healing of injured tissues. This review paper presents the multifunctional biomedical applications of alginate-based hydrogels and scaffolds in selected areas, highlighting the key effect of alginate and its influence on the essential properties of the selected biomedical applications. The first part covers scientific achievements for alginate in dermal tissue regeneration, drug delivery systems, cancer treatment, and antimicrobials. The second part is dedicated to our scientific results obtained for the research opus of hydrogel materials for scaffolds based on alginate in synergy with different materials (polymers and bioactive agents). Alginate has proved to be an exceptional polymer for combining with other naturally occurring and synthetic polymers, as well as loading bioactive therapeutic agents to achieve dermal, controlled drug delivery, cancer treatment, and antimicrobial purposes. Our research was based on combinations of alginate with gelatin, 2-hydroxyethyl methacrylate, apatite, graphene oxide and iron(III) oxide, as well as curcumin and resveratrol as bioactive agents. Important features of the prepared scaffolds, such as morphology, porosity, absorption capacity, hydrophilicity, mechanical properties, in vitro degradation, and in vitro and in vivo biocompatibility, have shown favorable properties for the aforementioned applications, and alginate has been an important link in achieving these properties. Alginate, as a component of these systems, proved to be an indispensable factor and played an excellent “role” in the optimal adjustment of the tested properties. This study provides valuable data and information for researchers and demonstrates the importance of the role of alginate as a biomaterial in the design of hydrogels and scaffolds that are powerful medical “tools” for biomedical applications.