The effect of inflammation management on pH, temperature, and bacterial burden

Cocooning Wound for Healing

Wound healing is highly sensitive to environmental conditions. Under solar radiation, elevated wound temperatures and UV-rays can induce oxidative stress, disrupt the wound environment, provoke inflammation, and even cause thermal injury. Lower wound temperatures may hinder angiogenesis and immune function, thus delaying recovery. Inspired by silkworm cocooning for thermal comfort during metamorphosis, we developed the wound cocoon (W-cocoon) using a portable high-speed electro-blow spinning (EBS) device. The W-cocoon integrates radiative cooling and thermal insulation properties, providing both cooling (3.9 °C) under sunlight and warming (1.9 °C) indoors. Based on animal studies, the W-cocoon promotes wound recovery in indoor scenarios, while under solar radiation, its high reflectivity and UV-blocking ratio mitigate the negative effects of radiation, thus optimizing wound healing. Additionally, the W-cocoon exhibits superhydrophobic and hemophobic properties, which endow the dressing with antifouling capabilities and reduce pain during dressing changes.

Glucose oxidase: An emerging multidimensional treatment option for diabetic wound healing

The healing of diabetic skin wounds is a complex process significantly affected by the hyperglycemic environment. In this context, glucose oxidase (GOx), by catalyzing glucose to produce gluconic acid and hydrogen peroxide, not only modulates the hyperglycemic microenvironment but also possesses antibacterial and oxygen-supplying functions, thereby demonstrating immense potential in the treatment of diabetic wounds. Despite the growing interest in GOx-based therapeutic strategies in recent years, a systematic summary and review of these efforts have been lacking. To address this gap, this review article outlines the advancements in the application of GOx and GOx-like nanozymes in the treatment of diabetic wounds, including reaction mechanisms, the selection of carrier materials, and synergistic therapeutic strategies such as multi-enzyme combinations, microneedle structures, and gas therapy. Finally, the article looks forward to the application prospects of GOx in aiding the healing of diabetic wounds and the challenges faced in translating these innovations to clinical practice. We sincerely hope that this review can provide readers with a comprehensive understanding of GOx-based diabetic treatment strategies, facilitate the rigorous construction of more robust multifunctional therapeutic systems, and ultimately benefit patients with diabetic wounds.

[Application of delayed replantation of degloving skin preserved at 4 in treatment of limb degloving injuries]

Objective

To investigate the effectiveness of delayed replantation of degloving skin preserved at 4℃ in treatment of limb degloving injuries.

Methods

Between October 2020 and October 2023, 12 patients with limb degloving injuries were admitted. All patients had severe associated injuries or poor wound conditions that prevented primary replantation. There were 7 males and 5 females; age ranged from 29 to 46 years, with an average of 39.2 years. The causes of injury included machine entanglement in 6 cases, traffic accidents in 5 cases, and sharp instrument cuts in 1 case. Time from injury to hospital admission was 0.5-3.0 hours, with an average of 1.3 hours. Injury sites included upper limbs in 7 cases and lower limbs in 5 cases. The range of degloving skin was from 5 cm×4 cm to 15 cm×8 cm, and all degloving skins were intact. The degloving skin was preserved at 4℃. After the patient's vital signs became stable and the wound conditions improved, it was trimmed into medium-thickness skin grafts for replantation. The degloving skin was preserved for 3 to 7 days. At 4 weeks after replantation, the viability of the degloving skin grafts was assessed, including color, elasticity, and sensation of pain. The Vancouver Scar Scale (VSS) was used to assess the scars of the skin grafts during follow-up.

Results

At 4 weeks after replantation, 8 cases of skin grafts completely survived and the color was similar with normal skin, with a survival rate of 66.67%. The elasticity of skin grafts (R0 value) ranged from 0.09 to 0.85, with an average of 0.55; moderate pain was reported in 4 cases, mild pain in 3 cases, and no pain in 5 cases. All patients were followed up 12 months. Over time, the VSS scores of all 12 patients gradually decreased, with a range of 4-11 at 12 months (mean, 6.8).

Conclusion

For limb degloving injuries that cannot be replanted immediately and do not have the conditions for deep low-temperature freezing preservation, the method of preserving the degloving skin at 4℃ for delayed replantation can be chosen.

Flexible bioelectronic systems with large-scale temperature sensor arrays for monitoring and treatments of localized wound inflammation

Continuous monitoring and closed-loop therapy of soft wound tissues is of particular interest in biomedical research and clinical practices. An important focus is on the development of implantable bioelectronics that can measure time-dependent temperature distribution related to localized inflammation over large areas of wound and offer in situ treatment. Existing approaches such as thermometers/thermocouples provide limited spatial resolution, inapplicable to a wearable/implantable format. Here, we report a conformal, scalable device package that integrates a flexible amorphous silicon-based temperature sensor array and drug-loaded hydrogel for the healing process. This system can enable the spatial temperature mapping at submillimeter resolution and high sensitivity of 0.1 °C, for dynamically localizing the inflammation regions associated with temperature change, automatically followed with heat-triggered drug delivery from hydrogel triggered by wearable infrared light-emitting-diodes. We establish the operational principles experimentally and computationally and evaluate system functionalities with a wide range of targets including live animal models and human subjects. As an example of medical utility, this system can yield closed-loop monitoring/treatments by tracking of temperature distribution over wound areas of live rats, in designs that can be integrated with automated wireless control. These findings create broad utilities of these platforms for clinical diagnosis and advanced therapy for wound healthcare.

The role of thermography in assessment of wounds. A scoping review

Assessment of wounds based on visual appearance has poor inter- and intra-rater reliability and it is difficult to differentiate between inflammation and infection. Thermography is a user-friendly quantitative image technique that collects the skin surface temperature pattern of the wound area and immediately visualizes the temperatures as a rainbow coloured diagram. The aim of this scoping review is to map and summarize the existing evidence on how thermography has been used to assess signs of inflammation in humans and animals with surgical or traumatic wounds. The method follows the Joanna Briggs Institute methodology. The databases searched were PubMed, Embase, CINAHL and Cochrane Library. 3798 sources were identified, 2666 were screened on title and abstract, 99 on full text and 19 studies were included for review. We found that the literature is diverse and originates from a variety of scientific fields. Thermography has been used to detect and predict inflammation and infection in surgical wounds. Grading systems based on the visual appearance correlate to temperature patterns detected with thermography. The general tendency is that thermography detects the temperature in a wound with inflammation to be warmer than a reference area or the same skin area before surgery. In a surgical wound the temperature is elevated 1-2 weeks after surgery due to natural physiological inflammation that induces healing, after 2 weeks the temperature of the wound area slowly and steady decreases to baseline over 1-3 months. If a secondary temperature peak happens during the healing phase of a surgical wound, it is likely that infection has occurred. Modern handheld thermographic cameras might be a promising tool for the clinician to quickly quantify the temperature pattern of surgical wounds to distinguish between inflammation and infection. However, firm evidence supporting infection thermography surveillance of surgical wounds as a technique is missing.

Smart photonic crystal hydrogels for visual glucose monitoring in diabetic wound healing

Diabetes is a global chronic disease that seriously endangers human health and characterized by abnormally high blood glucose levels in the body. Diabetic wounds are common complications which associate with impaired healing process. Biomarkers monitoring of diabetic wounds is of great importance in the diabetes management. However, actual monitoring of biomarkers still largely relies on the complex process and additional sophisticated analytical instruments. In this work, we prepared hydrogels composed of different modules, which were designed to monitor different physiological indicators in diabetic wounds, including glucose levels, pH, and temperature. Glucose monitoring was achieved based on the combination of photonic crystal (PC) structure and glucose-responsive hydrogels. The obtained photonic crystal hydrogels (PCHs) allowed visual monitoring of glucose levels in physiological ranges by readout of intuitive structural color changes of PCHs during glucose-induced swelling and shrinkage. Interestingly, the glucose response of double network PCHs was completed in 15 min, which was twice as fast as single network PCHs, due to the higher volume fraction of glucose-responsive motifs. Moreover, pH sensing was achieved by incorporation of acid-base indicator dyes into hydrogels; and temperature monitoring was obtained by integration of thermochromic powders in hydrogels. These hydrogel modules effectively monitored the physiological levels and dynamic changes of three physiological biomarkers, both in vitro and in vivo during diabetic wound healing process. The multifunctional hydrogels with visual monitoring of biomarkers have great potential in wound-related monitoring and treatment.

Can pin-site inflammation be detected with thermographic imaging? A cross-sectional study from the USA and Denmark of patients treated with external fixators

BACKGROUND AND PURPOSE

 Patients with external fixators are at risk of pin-site infection. A tool for objective monitoring of pin sites for evolving signs of infection is warranted. We aimed to investigate the temperature (MaxTp) difference between clean and visually inflamed pin sites using thermography and to establish the optimal cut-off value of MaxTp using thermography as a screening tool for inflammation detection.

METHODS

 This was a cross-sectional study performed in the USA and Denmark of patients with circular external fixators. Pin sites were visually judged by a surgeon or a nurse as clean or as showing signs of inflammation. The MaxTp was obtained at the pin site by thermographic imaging using an infrared camera (FLIR T540).

RESULTS

 We included 1,970 pin sites from 83 patients. The mean MaxTp for clean pin sites (n = 1,739) was 33.1°C (95% confidence interval [CI] 32.8-33.4) and the mean MaxTp for visual inflamed pin sites (n = 231) was 34.0°C (CI 33.6-34.3). The mean difference, when adjusted for repeated observations of patients and pin sites, was statistically significant with a difference of 0.9°C (CI 0.7-1.1) (P < 0.001). The area under the receiver operating characteristic curve for MaxTp as a screening tool to detect visual signs of inflammation was 0.71 (CI 0.65-0.76). The empirically optimal cut-off value was 34.1°C with a sensitivity of 65%, a specificity of 72%, a positive predictive value of 23%, and a negative predictive value of 94%.

CONCLUSION

 We found a statistically significant difference in mean temperature between pin sites with and without visual signs of inflammation. Thermography could be a promising tool for future point of care technology for monitoring inflammation around pin sites.

Intelligent electrospinning nanofibrous membranes for monitoring and promotion of the wound healing

The incidence of chronic wound healing is promoted by the growing trend of elderly population, obesity, and type II diabetes. Although numerous wound dressings have been studied over the years, it is still challenging for many wound dressings to perfectly adapt to the healing process due to the dynamic and complicated wound microenvironment. Aiming at an optimal reproduction of the physiological environment, multifunctional electrospinning nanofibrous membranes (ENMs) have emerged as a promising platform for the wound treatment owing to their resemblance to extracellular matrix (ECM), adjustable preparation processes, porousness, and good conformability to the wound site. Moreover, profiting from the booming development of human-machine interaction and artificial intelligence, a next generation of intelligent electrospinning nanofibrous membranes (iENMs) based wound dressing substrates that could realize the real-time monitoring of wound proceeding and individual-based wound therapy has evoked a surge of interest. In this regard, general wound-related biomarkers and process are overviewed firstly and representative iENMs stimuli-responsive materials are briefly summarized. Subsequently, the emergent applications of iENMs for the wound healing are highlighted. Finally, the opportunities and challenges for the development of next-generation iENMs as well as translating iENMs into clinical practice are evaluated.

Integrating Point-of-Care Bacterial Fluorescence Imaging-Guided Care with Continued Wound Measurement for Enhanced Wound Area Reduction Monitoring

AIM

This prospective observational study investigated wound area reduction (WAR) outcomes in a complex wound population composed of non-healing acute and chronic wounds. The relationship between bacterial autofluorescence signals and WAR was investigated. Area measurements were collected both manually and digitally, and both methods were compared for accuracy.

METHODS

Twenty-six participants with 27 wounds of varying etiologies were observed twice weekly for two weeks. Digital wound measurement, wound bacterial status assessment, and targeted debridement were performed through a point-of-care fluorescence imaging device (MolecuLight® i: X, MolecuLight Inc, Toronto, Canada). The wound area reduction (WAR) rate was calculated using baseline and last visit measurements. Statistical analyses, including t-tests, Fisher exact tests, the Wilcoxon signed rank test for method comparison, and ANOVA for bacterial subgroups, were applied as pertinent.

RESULTS

The overall average WAR was -3.80 cm2, or a decrease of 46.88% (manual measurement), and -2.62 cm2, or a 46.05% decrease (digital measurement via MolecuLight® device). There were no statistically significant differences between the WAR of acute and chronic wounds (p = 0.7877). A stepwise correlation between the WAR and bacterial status classification per fluorescence findings was observed, where persistent bacteria resulted in worse WAR outcomes. An overestimation of wound area by manual measurement was 23% on average.

CONCLUSION

Fluorescence imaging signals were linked to WAR outcome and could be considered predictive. Wounds exhibiting bacterial loads that persisted at the end of the study period had worse WAR outcomes, while those for which management was able to effectively remove them demonstrated greater WAR. Manual measurement of the wound area consistently overestimated wound size when compared to digital measurement. However, if performed by the same operator, the overestimation was uniform enough that the WAR was calculated to be close to accurate. Notwithstanding, single wound measurements are likely to result in overestimation.

Is my wound infected? A study on the use of hyperspectral imaging to assess wound infection

Introduction

Clinical signs and symptoms (CSS) of infection are a standard part of wound care, yet they can have low specificity and sensitivity, which can further vary due to clinician knowledge, experience, and education. Wound photography is becoming more widely adopted to support wound care. Thermography has been studied in the medical literature to assess signs of perfusion and inflammation for decades. Bacterial fluorescence has recently emerged as a valuable tool to detect a high bacterial load within wounds. Combining these modalities offers a potential objective screening tool for wound infection.

Methods

A multi-center prospective study of 66 outpatient wound care patients used hyperspectral imaging to collect visible light, thermography, and bacterial fluorescence images. Wounds were assessed and screened using the International Wound Infection Institute (IWII) checklist for CSS of infection. Principal component analysis was performed on the images to identify wounds presenting as infected, inflamed, or non-infected.

Results

The model could accurately predict all three wound classes (infected, inflamed, and non-infected) with an accuracy of 74%. They performed best on infected wounds (100% sensitivity and 91% specificity) compared to non-inflamed (sensitivity 94%, specificity 70%) and inflamed wounds (85% sensitivity, 77% specificity).

Discussion

Combining multiple imaging modalities enables the application of models to improve wound assessment. Infection detection by CSS is vulnerable to subjective interpretation and variability based on clinicians' education and skills. Enabling clinicians to use point-of-care hyperspectral imaging may allow earlier infection detection and intervention, possibly preventing delays in wound healing and minimizing adverse events.