Wound Hydration Research Articles

Approaches to scarless burn wound healing: application of 3D printed skin substitutes with dual properties of anti-infection and balancing wound hydration levels

Severe burn wounds face two primary challenges: dysregulated cellular impairment functions following infection and an unbalanced wound hydration microenvironment leading to excessive inflammation and collagen deposition. These results in hypertrophic scar contraction, causing significant deformity and disability in survivors. A three-dimensional (3D) printed double-layer hydrogel (DLH) was designed and fabricated to address the problem of scar formation after burn injury. DLH was developed using methacrylated silk fibroin (SFMA) and gelatin methacryloyl (GelMA) for the upper layer, and GelMA and hyaluronic acid methacryloyl (HAMA) for the lower layer. To combat infection, copper-epigallocatechin gallate (Cu-EGCG) was incorporated into the lower layer bioink, collectively referred to as DLS. To balance wound hydration levels, HaCaT cells were additionally encapsulated in the upper layer, designed as DLS/c. DLH demonstrated suitable porosity, appropriate mechanical properties, and excellent biocompatibility. DLS exhibited potent antimicrobial properties, exerted anti-inflammatory effects by regulating macrophage polarisation, and may enhance angiogenesis through the HIF-1α/VEGF pathway. In the DLS/c group, animal studies showed significant improvements in epidermal formation, barrier function, and epidermal hydration, accompanied by reduced inflammation. In addition, Masson's trichrome and Sirius red staining revealed that the structure and ratio of dermal collagen in DLS/c resembled that of normal skin, indicating considerable potential for scarless wound healing. This biomimetic matrix shows promise in addressing the challenges of burn wounds and aiming for scarless repair, with benefits such as anti-infection, epidermal hydration, biological induction, and optimised topological properties. Shown in Acknowledgements.

An in vitro and in vivo study of electrospun polyvinyl alcohol/chitosan/sildenafil citrate mat on 3D-printed polycaprolactone membrane as a double layer wound dressing

Double-layer dermal substitutes (DS) generally provide more effective therapeutic outcomes than single-layer substitutes. The architectural design of DS incorporates an outer layer to protect against bacterial invasions and maintain wound hydration, thereby reducing the risk of infection and the frequency of dressing changes. Moreover, the outer layer is a mechanical support for the wound, preventing undue tension in the affected area. A 3D-printed polycaprolactone (PCL) membrane was utilized as the outer layer to fabricate DS wound dressing. Simultaneously, a polyvinyl alcohol/chitosan/sildenafil citrate (PVA/CS/SC) scaffold was electrospun onto the PCL membrane to facilitate cellular adhesion and proliferation. Scanning electron microscopy (SEM) analysis of the PCL filaments revealed a consistent cross-sectional surface and structure, with an average diameter of 562.72 ± 29.15 μm. SEM results also demonstrated uniform morphology and beadless structure for the PVA/CS/SC scaffold, with an average fiber diameter of 366.77 ± 1.81 nm for PVA/CS. The addition of SC led to an increase in fiber diameter while resulting in a reduction in tensile strength. However, drug release analysis indicated that the SC release from the sample can last up to 72 h. Animal experimentation confirmed that DS wound dressing positively accelerated wound closure and collagen deposition in the Wistar rat skin wound model.

Smart Wound Monitoring and Healing Assessment System With Deep Learning Methods - A Systematic Review

This review describes a Deep Learning Smart Wound Monitoring (DL-SWM) system, focusing on the healing process of both acute and chronic skin wounds. Recognizing the impact of various factors such as environment, patient characteristics, and wound features on the healing timeline, the review emphasizes the need for more efficient wound monitoring methods. The proposed DL-SWM integrates biosensors, a microcontroller, and a fuzzy inference system to assess critical wound indicators, primarily focusing on hydration levels. The hardware design incorporates an Arduino-based biometric sensor device, while the fuzzy inference system predicts the impact of biomarkers on wound hydration. The review study also explores the segmentation of wounds using a Convolutional Neural Network (CNN) called MobileNetV2, providing detailed insights into the wound healing stages. In the literature review, various advancements in wound monitoring technologies, such as hydrogels, clinical decision-making systems, and wearable biological sensors, are discussed. The proposed DL-SWM is compared with existing methods through simulation analysis, demonstrating superior efficiency, accuracy, and lower error rates. The study concludes with the potential prospects of DL-SWM in revolutionizing wound monitoring and treatment, offering a more convenient and effective approach for healthcare practitioners and improving patient outcomes.

3D-printed hydrogels dressings with bioactive borate glass for continuous hydration and treatment of second-degree burns.

Recent advances in additive manufacturing have led to the development of innovative solutions for tissue regeneration. Hydrogel materials have gained significant attention for burn wound treatment in clinical practice among various advanced dressings due to their soothing and moisturizing activity. However, prolonged healing, pain, and traumatic removal due to the lack of long-term wound hydration are some of the challenges in the treatment of second-degree burn wounds. In this study, 3D-printed dressings were fabricated using gelatin, alginate, and bioactive borate glass (BBG) using an extrusion-based bioprinter. After ionic crosslinking, the 3D-printed dressings were characterized for mechanical properties, degradation rate, hydration activity, and in vitro cell viability using human fibroblasts. The results demonstrated that in 3D-printed dressings with 20 wt% BBG, Young's modulus increased by 105%, and 10-day degradation rate decreased by 62%. Addition of BBG prevented the burst release of water from hydrogel dressings and enabled the continuous water release for up to 10 days, which is crucial in treating second-degree burn wounds. 3D-printed hydrogel dressings with BBG showed long-term cell viability that can be a result of the accumulative release of therapeutic ions from BBG particulate. The in vivo wound healing functionality of the dressings was investigated using a rat model with a second-degree burn wound. Our animal study showed that the 3D-printed dressings with BBG exhibited faster wound closure, non-adhesive contact, non-invasive debridement, and non-traumatic dressing removal. Histological analysis suggested that 3D-printed dressings contributed to more uniform re-epithelialization and tissue remodeling compared to the non-printed hydrogels of the same compositions. Critically, 3D-printed dressings with BBG led to significant regeneration of hair follicles compared to the 3D-printed hydrogel, non-printed hydrogel, and the control groups. The superior outcome of the 3D-printed hydrogel-BBG20 dressings can be attributed to the bioactive formulation, which promotes moist wound healing for longer time periods, and the non-adhesive porous texture of the 3D-printed dressings with increased wound-dressing interactions. Our findings provided proof of concept for the synergistic effect of bioactive formulation and the porous texture of the 3D-printed hydrogel dressings incorporated with BBG on continuous water release and, consequently, on second-degree burn wound healing.

Endogenous Interleukin-10 Contributes to Wound Healing and Regulates Tissue Repair

IntroductionInterleukin-10 (IL-10) is essential in fetal regenerative wound healing and likewise promotes a regenerative phenotype in adult dermal wounds. However, the role of endogenous IL-10 in postnatal dermal wound healing is not well-established. We sought to determine the function of endogenous IL-10 in murine full thickness excisional wounds that are splinted to prevent contracture and mimic human patterns of wound closure. MethodsFull-thickness excisional wounds were made in wildtype (WT) and IL-10−/− mice on a C57BL/6J background (F/M, 8 wk old). In a subset of wounds, contraction was prevented by splinting with silicone stents (stenting) and maintaining a moist wound microenvironment using a semiocclusive dressing. Wounds were examined for re-epithelialization, granulation tissue deposition, and inflammatory cell infiltrate at day 7 and fibrosis and scarring at day 30 postwounding. ResultsWe observed no difference in wound healing rate between WT and IL-10−/− mice in either the stented or unstented group. At day 7, unstented IL-10−/− wounds had a larger granulation tissue area and more inflammatory infiltrate than their WT counterparts. However, we did observe more F4/80+ cell infiltrate in stented IL-10−/− wounds at day 7. At day 30, stented wounds had increased scar area and epithelial thickness compared to unstented wounds. ConclusionsThese data suggest that endogenous IL-10 expression does not alter closure of full thickness excisional wounds when wound hydration and excessive contraction of murine skin are controlled. However, the loss of IL-10 leads to increased inflammatory cell infiltration and scarring. These new findings suggest that IL-10 contributes to the regulation of inflammation without compromising the healing response. These data combined with previous reports of increased rates of healing in IL-10−/− mice wounds not controlled for hydration and contraction suggest an important role for murine wound healing models used in research studies of molecular mechanisms that regulate healing.

Continuous Diffusion of Oxygen Adjunct Therapy to Improve Scar Reduction After Cervicotomy – A Proof of Concept Randomized Controlled Trial

Dressing materials are known to influence post-operative surgical wound healing and scar formation (SF). A particular dressing that could promote wound hydration is essential to ensure quick epithelialization and reduce SF. This study examined the effectiveness of a novel Continuous Diffusion of Oxygen (CDO) dressing to reduce scar length post cervicotomy. A randomized controlled trial was performed in patients undergoing cervicotomy, either for thyroid or parathyroid disease. Patients were randomized to either control (CG) or intervention (IG) groups. The IG received a portable CDO system (TransCu O2, EO2 Concepts Inc., TX, USA), whereas the CG received a standard dressing for a 4-week period. The primary outcome was >10% of scar length reduction and %change in scar length. 21 patients were recruited (Age: 53 ± 16 years; 90% female; CG=9, IG=12). 5 patients were lost to follow-up. At 4 weeks, 88.8% of the IG significantly achieved >10% of scar reduction (versus CG=28.5%, d=0.48, P=0.049), showing a 40.4% smaller scar (15.7% versus 11.2%, d=0.13, P=0.72) compared to the CG. However, the difference was not significant. A sub-sample of patients undergoing thyroidectomy showed a significant scar reduction using CDO (IG=11.6% versus CG=5.1%, d=2.96, P=0.009). This is the first study to assess scar reduction using CDO adjunct therapy after cervicotomy. Advanced CDO dressings may assist wound healing showing improved outcomes for scar visualization in patients undergoing thyroidectomy. A larger sample is required to validate this observation.

Incidence and causes of negative dysphotopsia after uncomplicated cataract surgery – A randomized clinical trial

Purpose:The purpose of this study is to find incidence of negative dysphotopsia (ND) in eyes undergoing clear corneal phacoemulsification and identify its causes including corneal wound hydration and type of intraocular lens (IOL).Methods:In this randomized clinical trial, consenting adult patients undergoing phacoemulsification were randomized to receive a hydrophobic (Alcon Acrysof® SN60WF) or a hydrophilic acrylic IOL (CT Asphina® 603P, Carl Zeiss Meditec) in a 1:1 ratio. At time of surgery, eyes were again randomized in 1:1 fashion to receive stromal wound hydration or not (n = 80 each in four groups). Primary outcome measure was the incidence of ND between eyes receiving stromal hydration versus no hydration. Those with ND were observed for 5 years after surgery.Results:Of the 320 eyes, 29 (9.06%) reported ND of which 24 (83%) were transient. Eyes with wound hydration had significantly higher proportion of ND (n = 21/160, 13%) compared to no hydration (n = 8/160, 5%) (P = 0.01). Additionally, eyes with wound hydration were three times more likely to experience ND (odds ratio = 3.29, 95% CI = 1.3–8.2, P = 0.01). Majority of eyes (20/21, 95%) with ND after hydration had it transiently while half (4/8, 50%) of those with ND without wound hydration had it persistently at 6 weeks (P < 0.001) and continued to experience ND for 5 years but did not request intervention.Conclusion:ND occurred in 9% cases with majority being transient. Corneal wound hydration led to significant higher likelihood of experiencing transient ND. Those with persistent ND for more than 6 weeks (1.5%) continue to experience ND for at least 5 years.

Drug-impregnated, pressurized gas expanded liquid-processed alginate hydrogel scaffolds for accelerated burn wound healing

While the benefits of both hydrogels and drug delivery to enhance wound healing have been demonstrated, the highly hydrophilic nature of hydrogels creates challenges with respect to the effective loading and delivery of hydrophobic drugs beneficial to wound healing. Herein, we utilize pressurized gas expanded liquid (PGX) technology to produce very high surface area (~200 m2/g) alginate scaffolds and describe a method for loading the scaffolds with ibuprofen (via adsorptive precipitation) and crosslinking them (via calcium chelation) to create a hydrogel suitable for wound treatment and hydrophobic drug delivery. The high surface area of the PGX-processed alginate scaffold facilitates >8 wt% loading of ibuprofen into the scaffold and controlled in vitro ibuprofen release over 12–24 h. In vivo burn wound healing assays demonstrate significantly accelerated healing with ibuprofen-loaded PGX-alginate/calcium scaffolds relative to both hydrogel-only and untreated controls, demonstrating the combined benefits of ibuprofen delivery to suppress inflammation as well as the capacity of the PGX-alginate/calcium hydrogel to maintain wound hydration and facilitate continuous calcium release to the wound. The use of PGX technology to produce highly porous scaffolds with increased surface areas, followed by adsorptive precipitation of a hydrophobic drug onto the scaffolds, offers a highly scalable method of creating medicated wound dressings with high drug loadings. Statement of SignificanceWhile medicated hydrogel-based wound dressings offer clear advantages in accelerating wound healing, the inherent incompatibility between conventional hydrogels and many poorly water-soluble drugs of relevance in wound healing remains a challenge. Herein, we leveraged supercritical fluids-based strategies to both process and subsequently impregnate alginate, followed by post-crosslinking to form a hydrogel, to create a very high surface area alginate hydrogel scaffold loaded with high hydrophobic drug contents (here, >8 wt% ibuprofen) without the need for any pore-forming additives. The impregnated scaffolds significantly accelerated burn wound healing while also promoting regeneration of the native skin morphology. We anticipate this approach can be leveraged to load clinically-relevant and highly bioavailable dosages of hydrophobic drugs in hydrogels for a broad range of potential applications.

Comparison between intracameral ceftazidime &amp; cefuroxime for the prevention of post-operative endophthalmitis

Purpose: To compare the efficacy and safety of intracameral injection of ceftazidime and cefuroxime during cataract surgery for the prevention of post-operative endophthalmitis.&#x0D; Study Design: Quasi experimental study.&#x0D; Place and Duration of Study: Ophthalmology Department Unit-1, Lahore General Hospital, Lahore.&#x0D; From November 2016 to March 2018.&#x0D; Material and Methods: Patients undergoing cataract surgery in the eye department were selected by convenient sampling to receive prophylactic intracameral antibiotics at the end of routine cataract surgery. Patients were divided into two groups; group A received Cefuroxime and group B received Ceftazidime both as 1 mg /0.1ml intracameral injections at the end of the surgery after wound hydration and before chamber formation. The patients were examined pre and post operatively on slit lamp and the number of cells in the anterior chamber (A/C) were counted on day 1, week 1 and week 6 after surgery.&#x0D; Results: Out of total 260 patients 130 were allocated to each group. On first post-operative day in Group A, A/C cell counts were grade 1 in 22 patients, grade 2 in 93 patients, grade 3 in 14 patients and Grade 4 in 1 patient. In group B, A/C cell counts were grade 1 in 11 patients, grade 2 in 96 patients, grade 3 in 20 patients and grade 4 in 3 patients. After one week, in group A, cell counts were grade 0 in 27 patients, grade 1 in 100 patients, grade 2 in 2 patients and grade 4 in 1 patient. While in group B, A/C cell counts were Grade 0 in 23 patients, grade 1 in 102 patients, grade 2 in 3 patients and grade 3 in 2 patients. After 6 weeks no patient in any group showed any activity in the anterior chamber.&#x0D; Conclusion: There is little difference in efficacy of intracameral ceftazidime antibiotic prophylaxis as compared to the intracameral cefuroxime.

Smart Wound Hydration Monitoring Using Biosensors and Fuzzy Inference System

Skin wounds either minor or chronic may heal up with different time durations. But, this time duration of healing could not be easily predicted as healing is affected by different factors, e.g., age, nutrition, medication, and surroundings. Despite these factors, wound characteristic also plays a role in the healing process. Wound characteristics include wound size, wound type, internal and external wound environment, body temperature, body oxygenation, wound hydration, and infection. Therefore, monitoring of wound healing also required careful consideration of wound characteristics. Although the healthcare domain contains many applications for detection and monitoring of diseases, the wound care domain requires efficient techniques and sensing systems for the identification of wound biomarkers such as temperature, blood pressure, oxygen, and infection status of wound using biosensors. In the current research, we provide a wound care solution based on a biosensor-based sensing system to measure basic biomarkers, considered as major wound characteristics, i.e., body temperature and body oxygenation, and design a fuzzy inference system to predict their effect on wound hydration, which ultimately recommends necessary actions to boost healing.

Intraocular pressure and wound state immediately after long versus short clear corneal incision cataract surgery.

To compare the intraocular pressure (IOP) and wound state immediately after cataract surgery for eyes with a long clear corneal incision (CCI) with those for eyes with a short CCI. Randomized clinical trial. One hundred twenty-eight eyes of 128 patients scheduled for phacoemulsification were randomly assigned to undergo long (≥ 1.75 mm) or short (< 1.75 mm) CCI (2.4-mm wide). IOP was measured using a rebound tonometer preoperatively, at the conclusion of surgery, and at 30 min, 60 min, 120 min, 180 min, and 24 h postoperatively. Wound architecture determined using anterior segment-optical coherence tomography and flare intensity was examined at 60 min postoperatively. The mean incision length was significantly longer in the long CCI group (2.02 ± 0.19 mm) than in the short CCI group (1.50 ± 0.13mm; P < .0001). The mean IOP significantly increased at 120 min and 180 min postoperatively (P ≤ .0005) and returned to the preoperative level within 24 h. The mean IOP did not differ significantly between the long and short CCI groups at any follow-up period. The incidence of IOP lower than 10 mmHg did not differ significantly between the groups. The mean flare intensity was significantly greater in the short CCI group than in the long CCI group (P = .0122). The wound architecture was similar between the groups. IOP and wound architecture were comparable between eyes with a long CCI and eyes with a short CCI in the immediate postoperative periods up to 24 h, suggesting that wound stability is equivalent when the CCI is securely closed with wound hydration.

Linking challenges in wound healing: key highlights from the Hartmann congress.

With a special focus on advanced wound healing (wound bed preparation, epithelialisation and hydration) and negative pressure wound therapy, the Hartmann LINK for Wound Healing Congress took place in Belfast, Northern Ireland, on 19 September. The event aimed to promote the latest advances in wound care and highlight the main challenges that clinicians face when treating different types of wounds. Annabel De Coster, editor of the British Journal of Community Nursing, gives an overview of selected talks from the congress.

Wound stability and surgically induced corneal astigmatism after transconjunctival single-plane sclerocorneal incision cataract surgery.

To compare intraocular pressure (IOP) immediately after cataract surgery, and surgically induced corneal astigmatism (SIA) and corneal shape changes between eyes with transconjunctival single-plane sclerocorneal incisions (TSSIs) and eyes with clear corneal incisions (CCIs). Bilateral eyes of 64 patients undergoing phacoemulsification were randomized to undergo 2.4-mm temporal TSSI or CCI. IOP was measured preoperatively, and in the immediate postoperative periods. SIA was determined using vector analysis, and corneal shape changes and irregular astigmatism were evaluated using a videokeratography preoperatively, and in the early postoperative periods. Wound hydration was performed in 23 eyes (35.9%) of the TSSI group and in 60 (93.8%) of the CCI group (P<0.0001). Mean IOP was significantly higher in the TSSI group than in the CCI group at 30, 60, and 120min postoperatively (P≤0.0179). SIA tended to be smaller in the TSSI group than the CCI group, but the difference was not significant. The higher order irregular astigmatism was smaller in the TSSI group than in the CCI group at 2days (P=0.0312). The videokeratography revealed a wound-related flattening postoperatively in both groups; this change disappeared within 4weeks in the TSSI group, whereas it persisted until 12weeks in the CCI group. IOP was significantly higher immediately after TSSI than after CCI and required less wound hydration, suggesting better stability with TSSI. Higher order irregular astigmatism and wound-related corneal flattening were smaller after TSSI than after CCI in the early periods, suggesting that fewer corneal shape changes with TSSI.

Effect of intraocular lens insertion speed on surgical wound structure during phacoemulsification

Purpose The purpose of this study was to evaluate the difference in the effect of two speeds of intraocular lens (IOL) insertion on the clear corneal wound structure of two sizes: 2.4 and 2.2 mm. Setting This study was conducted in the Department of Ophthalmology, Faculty of Medicine, Alexandria University, Egypt. Design This is a prospective randomized clinical trial. Patients and methods Eyes that had phacoemulsification and Acrysof IQ IOL implantation using a screw-plunger-type injector were randomly divided into two equal-sized groups as follows. Group A included 40 eyes in which an incision of 2.4 mm size was used. These eyes were randomly divided into two equally sized subgroups: group AF with fast IOL insertion [1 revolution per second (rps)] plunger speed, and group AS with slow IOL insertion (1/4 rps). Group B included 40 eyes in which an incision size of 2.2 mm was used. These eyes were randomly divided into two equally sized subgroups: BF with fast IOL insertion (1 rps) and BS with slow IOL insertion (1/4 rps). The change in wound size before IOL insertion and after IOL insertion, need for corneal hydration, and surgically induced astigmatism were compared. Results The change in wound size was significantly larger in groups AS and BS than in groups AF and BF (P=0.002 and 0.008, respectively). Corneal hydration was required in 35% of cases in group AF and in 65.0% of cases in group AS. In group B, wound hydration was required in 30.0% of cases in group BF and 60% of cases in group BS. The differences were statistically not significant (P=0.057 and 0.736, respectively). Conclusion With an injector system, slow IOL insertion affected clear corneal wound size to a greater extent than fast insertion in the two wound sizes: 2.4 and 2.2 mm.

Reduction of Postoperative Scar Formation With Silicone Sheeting: 2 Case Studies

Elective surgeries account for millions of acquired scars annually. Many of these scars can be problematic, being aesthetically unpleasant and causing discomfort. Silicone gel sheeting has been shown to be efficacious for the prevention and treatment of problematic scars. By wound hydration, along with other factors, silicone dressings are thought to decrease scarring. However, we found the usual treatment was commonly started after epithelialization of the incision site. The current standard of care in wound healing is to promote a moist wound environment to ensure quick epithelialization and decrease excessive scar formation. With that standard in mind, after foot surgery was performed on 2 patients, silicone sheeting was applied immediately in order to compare its effects with those of standard moist wound healing (XEROFORM Petrolatum Gauze).

Cannula ejection into the cornea during wound hydration

Purpose: To report a case of iatrogenic corneal perforation from an ejected cannula.Methods: Case report.Results: During corneal tunnel hydration following a successful phacoemulsification procedure, a hydration cannula on a Luer...

019 Effectiveness of Oasis® Wound Matrix Versus Regranex® in Treating Diabetic Wounds

Background: Current care for chronic diabetic wounds involves maintaining wound hydration, providing protection from infection through regular dressing changes, and providing appropriate pressure relief. Even with the best care available, such therapies lead to effective wound healing in only 24% of ulcers within 12 weeks. Treatment of chronic ulcers with recombinant growth factors only moderately improves 12‐week healing rates, to 34%. A new, bioactive material, the Oasis® Wound Matrix, comprises a full complement of structural extracellular matrix components and associated growth factors and may be more effective in managing chronic wounds than other current alternatives. Method: Interim data from 88 evaluable patients in this multicenter, prospective, randomized clinical trial are presented. Patients diagnosed with chronic, full‐thickness, diabetic ulcers were enrolled and randomly assigned to receive either weekly treatments of Oasis Wound Matrix or daily treatments of Regranex® becaplermin gel. All wounds were carefully cleaned and irrigated weekly for the duration of the study, with debridement performed as needed; wound areas were recorded to track the rate of wound closure. Incidence of complete wound healing by 12 weeks was evaluated. Results: Study groups were balanced with respect to patient age and gender. Currently, 53%(24/45) of patients receiving Oasis wound matrix are considered healed versus 35%(15/43) of patients receiving treatment with Regranex. Conclusion: These data clearly demonstrate Oasis wound matrix is at least as effective as becaplermin gel in managing chronic, full‐thickness, diabetic ulcers.

Update on High-Voltage Pulsed Current Research and Application

Electrotherapy is an effective modality for wound management. Studies show electric stimulation increases circulation and inhibits bacterial growth. The skin has electrical properties that require wound hydration for proper functioning. High-voltage pulsed current also may be used for edema reductio

The effect of backing materials on keratinocyte autograft take

A porcine model has been established to study keratinocyte autografts as a model of human keratinocyte grafting. Keratinocyte autografts were placed on 104 full thickness wounds in 13 pigs and backed with 3 dressings which varied in their ability to maintain an occlusive environment. Sixteen control wounds were ungrafted. No take was found using a backing of woven viscose and cotton gauze. Take was 20% at day 16 using a backing of woven viscose and paraffin gauze. Serial biopsies showed that keratinocytes frequently attached to the interstices of the viscose dressing and difficulty in detaching the viscose caused loss of epidermis. Hydrogel sheet backing made assessment at day 10 difficult because of wound hydration but dressing removal, enabling exudate evaporation, produced 22% take at day 13. The development of improved dressing techniques is certainly necessary for improved graft take.