Bioinspired pH-sensitive riboflavin controlled-release alkaline hydrogels based on blue crab chitosan: Study of the effect of polymer characteristics

Photocrosslinked carboxymethylcellulose-based hydrogels: Synthesis, characterization for curcumin delivery and wound healing

Skin could protect our body and regenerate itself to against dysfunctional and disfiguring scars when faced with external injury. As wound dressings, hydrogels are biocompatible, hydrophilic and have a 3D structure similar to the extracellular matrix (ECM). In particular, hydrogels with drug-releasing capabilities are in acute wound healing. In this paper, photocrosslinked hydrogels served as wound dressing based on sodium carboxymethylcellulose (CMC) were prepared to promote wound healing. Photocrosslinked hydrogels were prepared by grafting lysine and allyl glycidyl ether (AGE) onto CMC and encapsulating curcumin (Cur). The synthesized hydrogels had the unique 3D porous structure with a swelling ratio up to 1300 % in aqueous solution. The drug release ratios of the hydrogels were 20.8 % in acid environment, and 14.4 % in alkaline environment. Notably, the hydrogels showed good biocompatibility and antibacterial properties and also exhibited the ability to accelerate the process of skin wound healing while prevent inflammation and scar formation when applied to a mouse skin wound model. As a result, the prepared hydrogels Gel-CLA@Cur showed great potential in wound healing.

Advancements in hydrogel-based drug delivery systems for the treatment of inflammatory bowel disease: a review

Inflammatory bowel disease (IBD) is a chronic disorder that affects millions of individuals worldwide. However, current drug therapies for IBD are plagued by significant side effects, low efficacy, and poor patient compliance. Consequently, there is an urgent need for novel therapeutic approaches to alleviate IBD. Hydrogels, three-dimensional networks of hydrophilic polymers with the ability to swell and retain water, have emerged as promising materials for drug delivery in the treatment of IBD due to their biocompatibility, tunability, and responsiveness to various stimuli. In this review, we summarize recent advancements in hydrogel-based drug delivery systems for the treatment of IBD. We first identify three pathophysiological alterations that need to be addressed in the current treatment of IBD: damage to the intestinal mucosal barrier, dysbiosis of intestinal flora, and activation of inflammatory signaling pathways leading to disequilibrium within the intestines. Subsequently, we discuss in depth the processes required to prepare hydrogel drug delivery systems, from the selection of hydrogel materials, types of drugs to be loaded, methods of drug loading and drug release mechanisms to key points in the preparation of hydrogel drug delivery systems. Additionally, we highlight the progress and impact of the hydrogel-based drug delivery system in IBD treatment through regulation of physical barrier immune responses, promotion of mucosal repair, and improvement of gut microbiota. In conclusion, we analyze the challenges of hydrogel-based drug delivery systems in clinical applications for IBD treatment, and propose potential solutions from our perspective.

Anti-bacterial dynamic hydrogels prepared from O-carboxymethyl chitosan by dual imine bond crosslinking for biomedical applications

Imine dynamic hydrogels are synthesized via dual-imine bond crosslinking from O-carboxymethyl chitosan (CMCS) and a water soluble dynamer using a 'green' approach. Three dynamers are prepared through reaction of benzene-1,3,5-tricarbaldehyde and di-amino Jeffamine with molar mass of 500, 800 and 1900, respectively. Hydrogels, namely H500, H800 and H1900 are then obtained by mixing CMCS and dynamer aqueous solutions. FT-IR confirms the formation of hydrogels via imine bonding. H1900 presents larger pore size and higher storage modulus as compared to H500 and H800 due to the higher molar mass of Jeffamine linker. The hydrogels exhibit pH sensitive swelling behavior due to electrostatic attraction or repulsion in the pH range from 3 to 10. The highest swelling ratio is obtained at pH 8, reaching 7500% for H800. Self-healing of hydrogels is evidenced by rheological measurements with alternatively applied low and high strains, and by using a macroscopic approach with re-integration of injected filaments. Furthermore, the H1900 membrane exhibits outstanding antibacterial activity against an E. coli suspension at 10⁸ CFU mL^-1. Therefore, dynamic hydrogels synthesized from CMCS and Jeffamine present outstanding rheological, swelling, self-healing and antibacterial properties, and are most promising as healthcare material in wound dressing, drug delivery and tissue engineering.