Bacterial Growth-Induced Tobramycin Smart Release Self-Healing Hydrogel for Pseudomonas aeruginosa-Infected Burn Wound Healing

Abstract

Burns are a common health problem worldwide and are highly susceptible to bacterial infections that are difficult to handle with ordinary wound dressings. Therefore, burn wound repair is extremely challenging in clinical practice. Herein, a series of self-healing hydrogels (QCS/OD/TOB/PPY@PDA) with good electrical conductivity and antioxidant activity were prepared on the basis of quaternized chitosan (QCS), oxidized dextran (OD), tobramycin (TOB), and polydopaminecoated polypyrrole nanowires (PPY@PDA NWs). These Schiff base crosslinks between the aminoglycoside antibiotic TOB and OD enable TOB to be slowly released and responsive to pH. Interestingly, the acidic substances during the bacteria growth process can induce the on-demand release of TOB, avoiding the abuse of antibiotics. The antibacterial results showed that the QCS/OD/TOB/PPY@PDA9 hydrogel could kill high concentrations of Pseudomonas aeruginosa (PA), Staphylococcus aureus, and Escherichia coli in a short time and showed a bactericidal effect for up to 11 days in an agar plate diffusion experiment, while showing good in vivo antibacterial activity. Excellent and long-lasting antibacterial properties make it suitable for severely infected wounds. Furthermore, the incorporation of PPY@PDA endowed the hydrogel with near-infrared (NIR) irradiation assisted bactericidal activity of drug-resistant bacteria, conductivity, and antioxidant activity. Most importantly, in the PA-infected burn wound model, the QCS/OD/TOB/PPY@PDA9 hydrogel more effectively controlled wound inflammation levels and promoted collagen deposition, vascular generation, and earlier wound closure compared to Tegaderm dressings. Therefore, the TOB smart release hydrogels with on-demand delivery are extremely advantageous for bacterial-infected burn wound healing.

Highly stretchable, self-healing elastomer hydrogel with universal adhesion driven by reversible cross-links and protein enhancement

“…The self-healing properties of the designed hydrogels discussed above display the key effect of the dynamically reversible borate bonds formed between borate and the -OH groups on PHEMAA. To further illustrate the complexation interaction in the formation and self-healing process of the hydrogel, 11 B NMR measurements were performed. As with PVA, PHE-MAA with a hydroxyl group in each monomer unit should possess a succession of diols to enable the formation of borate ester bonds.…”

“…49 Indeed, according to our experiment, PHEMAA/borax can form a self-standing hydrogel at 10 wt% HEMAA content, whereas PHEMAA without borax cannot form a self-standing hydrogel, confirming that the formation of the self-healing homopolymer gel can be ascribed to the complexation between borate and -OH groups. Besides, it should be noted that the 11 B NMR spectrum of boron in a HEMAA/borax mixture without UV radiation shows a free, uncomplexed boric acid form (Fig. S12b, ESI †), indicating the necessity of -OH groups in interconnected monomer units within polymer chains for complexation.…”

“…For example, hydrogels having good mechanical toughness, fast self-healing and adhesive abilities can be integrated as wound dressings. 11,12 Integrated hydrogels with good mechanical performances, self-healing ability and conductivity can be used as electronic skins. 3,13 So, it is of great importance to design engineered hydrogels with excellent mechanical properties and multifunctionality to satisfy practical requirements.…”

A nanofiber hydrogel derived entirely from ocean biomass for wound healing

“…Therefore, there is an urgent need to obtain new isolates from marine biological waste for medical research under cost-effective and sustainable conditions [30] . In addition, wound dressings in the field of biodegradable medical scaffolds can be prepared by microfluidic [31] , electrostatic spinning [32] , polymer synthesis [33], [34], [35] , hydrogel and other forms [36], [37], [38], [39] . As a flexible body, hydrogel has special advantages in the field of wound repair and other medical scaffolds: it keeps the wound moist, prevents the wound from dehydration, absorbs additional secretions, allows gas exchange, and is easy to remove without damaging the wound bed [40] .…”

Supramolecular Hydrogel Dressing: Effect of Lignin on the Self-Healing, Antibacterial, Antioxidant, and Biological Activity Improvement

“…Hydrogel is a kind of three-dimensional network polymer material formed by chemical and/or physical cross-linking, which has a high moisture content and soft texture. − Because of their excellent biocompatibility, controllable physical properties, natural drug-loading structure, and rich functional groups, hydrogels are gradually becoming the research hotspot and have been successfully applied in the treatment of skin defects, infected wounds, burn wounds, and wet wounds in the body. − To prevent potential wound infection, the key requirement of hydrogel wound dressings is efficient antibacterial ability. , Several antibacterial agents, such as organic small-molecule antibiotics and silver ion antibacterial agents, have been introduced into the hydrogel wound dressings as active antibacterial substances. , However, due to the limited bactericidal spectrum, shorter timeliness, and relatively slow bactericidal effect, their overall effect of preventing wound infection can still not meet the clinical requirements. − Therefore, some physical antibacterial substances have been developed and applied in the field of hydrogel wound dressings. , Among these antibacterial substances, chitosan has great advantages and application potential. , The positive charge of chitosan will interact with phospholipid bilayers in bacterial cell membranes and destroy the integrity of cell membranes, eventually resulting in bacterial apoptosis. This special antibacterial mechanism endows chitosan with good and broad-spectrum antibacterial activity against common Gram-positive and Gram-negative organisms .…”