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Background Burn wound progression is a significant problem as burns initially thought to be superficial can actually become full thickness over time. Cooling is an efficient method to reduce burn wound conversion. However, if the cooling agent is below room temperature, depending on the wound size the patient is at risk of hypothermia. Additionally, tissue perfusion is reduced leading to an aggravation of burn wound progression. We investigated if wound dressings based on non-pre-cooled bacterial nanocellulose (BNC) with a high water content cool a burn just by evaporation and reduce the intradermal damages in the skin. Material and methods In a human ex-vivo model, skin explants underwent contact burns using a 100 °C hot steel block. The burned areas were divided into two groups of which one was cooled with a BNC-based wound dressing. Intradermal temperature probes measured temperature in cooled and uncooled burn sites over 24 h. For histological assessments of the burned areas biopsies were taken at different time points. High mobility group box-1 (HMBG1) staining served as marker for cell vitality and necrosis in the different skin layers. Results Intradermal temperature measurement showed that application of the BNC-based wound dressing reduced temperature significantly in burned skin. This cooling effect resulted in a maximum temperature difference of 6.4 ± 1.9 °C and a significant mean reduction of the area under the curve in the first hour after burn of 62% (p Conclusion Based on our results, BNC-based wound dressings cool a burn. Intradermal temperature as well as thermal damage of the tissue was reduced. The tested BNC-based wound dressing can be used without pre-cooling to cool a burn as well as to reduce the burn BNC-based wound progression through its evaporation cooling effect.

Introduction Cooling of burn injuries is most important, not only to reduce pain but also to reduce the intradermal damage as well as the burn wound conversion. Studies have shown that cooling for about 20 to 30 minutes using only plain tap water at moderate temperature is most efficient resulting in least intradermal damage. However, many burn injuries reach the hospital without any pre-clinical cooling, possibly due to the lack of a cooling agent. After a pilot study, we investigated if a bacterial nanocellulose (BNC)-based wound dressing containing about 95% water can cool a burn injury and if so the effect suffices to reduce the damage in the skin. Methods Skin explants from human donors were burned with inflicted a contact burn injury, of which half were treated with a BNC-based wound dressing and a paraffin gauze dressing. Intradermal temperature sensors measured the temperature changes in the dermis over the course of 24 hours. Biopsies were taken for histological evaluation at different time points. Results The intradermal measurements show high temperature spikes at the moment of the burn injuries. After the application of a BNC-based wound dressing the intradermal skin temperature was significantly reduced. The area under the curve in the treated group was significantly less than the untreated. The histological assessment showed according results with less damage in the treated group in comparison to the untreated. Conclusions Bacterial nanocellulose-based wound dressings with high water content significantly lower the intradermal temperature after a contact burn and reduce the thermal damage inflicted to the skin. A secondary dressing that permits the water to evaporate slower additionally prolongs the cooling effect. The use of such a wound dressing could find use in a preclinical setting where other cooling options are not available. Applicability of Research to Practice The findings of this experiment should be tested in an in-vivo setting prior to clinical use to investigate the possibility of inducing hypothermia with this treatment.

Introduction Inflammation is part of the physiological phases of wound healing. It serves the purpose to attract different immune cells in order to clean the wound from pathogens and debris and create an ideal environment for fibroblasts and keratinocytes to differentiate, migrate and divide in order to close the wound. Pathological inflammation caused by many different factors is often the underlying cause of prolonged wound healing and unfavourable outcome in burn patients. We wanted to investigate what influence an induced hyper-inflammation on wound healing has in a controlled environment. Methods In a porcine wound model, pigs received full-thickness wounds on their backs where hyper-inflammation was induced by application of a chemotherapeutic for 6 days. Control wounds were left without induction. Wound were scored on a daily basis for 16 days in total and biopsies were taken for RNA analysis as well as histological assessment. Results The results showed a rise in inflammation of the wounds and the surrounding tissue due to the induction. The wounds healed slower, needing up to seven more days to completely heal. The results of the RNA analysis showed high values of pro-inflammatory cytokines after the induction in comparison to the baseline and control wounds. Histological assessment showed thick layers of necrosis, adipocyte as well as leucocyte infiltration in the hyper-inflamed wounds compared to completely healed control wounds with all layers of epidermis visible. Conclusions Hyper-inflammation, even just for a short period of time, can significantly prolong the time of wound healing. These findings underline the importance of preventing and treating wound infections of burn patients in order to support physiological wound healing as well as to avert complications such as infections with multi-resistant microbes that are associated with prolonged hospital stays. Applicability of Research to Practice The findings of these experiments cannot be directly applied to practice however, the influence of inflammation should kept in mind when treating burn patients.