clay and Burns

Bacterial infections of burn wounds are a significant problem that usually slows or stops the process of burn wounds healing. The use of topical antibiotics based on a novel drug delivery system could overcome the limitations of burn wound healing. In this work, the development of new wound dressings based on nanocomposite film of polyvinyl alcohol (PVA) and halloysite nanotubes (HNT) for the delivery of minocycline was investigated. These elastomeric nanocomposites were prepared based on HNT surface modification by APTES and then PVA coating by LbL strategy. The resulting nanocomposites were characterized by FT-IR, XRD, zeta potential, Tg analysis, FESEM, and antibacterial studies. The biodegradability and water uptake of the film were evaluated, the results of which revealed the absorption of scarring and non-degradation of the nanocomposite during treatment. Because minocycline decomposes by light, increasing photostability was another goal that was achieved. The release profile of the drug from the nanocomposite was studied, and it was found to be consistent with the Korsmeyer-Peppas model. In-vitro studies showed the antibacterial effect of nanocomposite on exposure to Gram-positive and Gram-negative bacteria. Due to the properties of the resulting nanocomposite film, it can be considered as a promising candidate for wound healing. In-vivo studies, cell culture, neuroprotective and anti-inflammatory effects may be investigated to develop this wound dressing in the future.

Topics: Anti-Bacterial Agents; Anti-Inflammatory Agents; Bandages; Biocompatible Materials; Burns; Clay; Gram-Negative Bacteria; Gram-Positive Bacteria; Minocycline; Nanocomposites; Nanotubes; Neuroprotective Agents; Polyvinyl Alcohol; Spectroscopy, Fourier Transform Infrared; Wound Healing

Second-degree burn injury is the most common type of burn injury, which usually takes 2-3 weeks for complete healing. However, such patients suffer with intense pain associated with development of hyperalgesia and allodynia. Here, we prepare a silver clay patch using montmorillonite clay, betaine, and silver nitrate. Later, the silver clay patches were loaded with fentanyl. Furthermore, the patches were fabricated into burn wound dressings. The dressings were first subjected to ex vivo skin penetration studies and were later evaluated for thermal hyperalgesia and mechanical allodynia using second-degree burn injury rodent model. Our results show that application of fentanyl-loaded dermal clay (FLDC) dressings for 3 h showed significant increase of paw withdrawal latency (p <0.001) against hyperalgesia starting from 30 min after removal of patch to up to 6 h. Similarly, the FLDC dressings also potentiated the paw withdrawal threshold for up to 4 h after application (p <0.001). From these studies, we can conclude that FLDC dressings are ideal topical formulations for better management of pain in second-degree burns.

Topics: Animals; Bandages; Burns; Clay; Disease Models, Animal; Fentanyl; Hyperalgesia; Male; Pain; Rats; Rats, Sprague-Dawley; Skin; Wound Healing

In this study, poly(L-lactide) (PLLA)/halloysite nanotube (HNT) electrospun mats were prepared as a dual-drug delivery system. HNTs were used to encapsulate polymyxin B sulphate (a hydrophilic drug). Dexamethasone (a hydrophobic drug) was directly dissolved in the PLLA solution. The drug-loaded HNTs with optimised encapsulation efficiency were then mixed with the PLLA solution for subsequent electrospinning to form composite dual-drug-loaded fibre mats. The structure, morphology, degradability and mechanical properties of the electrospun composite mats were characterised in detail. The results showed that the HNTs were uniformly distributed in the composite PLLA mats. The HNTs content in the mats could change the morphology and average diameter of the electrospun fibres. The HNTs improved both the tensile strength of the PLLA electrospun mats and their degradation ratio. The drug-release kinetics of the electrospun mats were investigated using ultraviolet-visible spectrophotometry. The HNTs/PLLA ratio could be varied to adjust the release of polymyxin B sulphate and dexamethasone. The antibacterial activity in vitro of the mats was evaluated using agar diffusion and turbidimetry tests, which indicated the antibacterial efficacy of the dual-drug delivery system against Gram-positive and -negative bacteria. Healing in vivo of infected full-thickness burns and infected wounds was investigated by macroscopic observation, histological observation and immunohistochemical staining. The results indicated that the electrospun mats were capable of co-loading and co-delivering hydrophilic and hydrophobic drugs, and could potentially be used as novel antibacterial wound dressings.

Topics: Aluminum Silicates; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Bacteria; Bacterial Infections; Burns; Clay; Dexamethasone; Drug Delivery Systems; Male; Nanotubes; Polyesters; Polymyxin B; Rats, Sprague-Dawley

Currently available wound dressings to heal thermal and chronic wounds are unable to respond to the challenges of resistance to bacterial infection, protein adsorption, and increased levels of wound exudates. To this end, we have conceived the fabrication of a new and ideal wound dressing with a number of key attributes. They include effective antimicrobial activity in a controlled manner, ultralow fouling property that provides resistance to protein adsorption and bacterial adhesion, maintain a moist but not saturated environment to promote healing, and is non-adherent and effective in the presence of heavy wound exudate. The novel approach to reduce infection and bacterial colonization involves incorporation of a unique silver-clay nanohybrid architecture in zwitterionic polymer, poly(sulfobetaine). The innovative concept of silver-clay hybrid structure enables us to obtain high, sustained, and diffusion-controlled antimicrobial activity of silver eluting polymer. The sustained and diffusion-controlled high antimicrobial efficiency is obtained through a process involving in situ precipitation of silver nanoparticles with large surface area on the surface of clay platelets. Furthermore, the use of recently developed zwitterionic polymer, poly(sulfobetaine) [poly(SB)] for wound dressing, provides antifouling property, which resists protein adsorption.

Topics: Aluminum Silicates; Animals; Anti-Infective Agents; Bacterial Adhesion; Bandages; Bentonite; Burns; Cell Adhesion; Cells, Cultured; Clay; Escherichia coli; Fibroblasts; Hydrophobic and Hydrophilic Interactions; Mice; Microbial Sensitivity Tests; Nanocomposites; Silver; Staphylococcus aureus; Wound Healing; Wound Infection