Organic light emitting diode improves diabetic cutaneous wound healing in rats

Fusion protein of FGF21 and elastin-like peptide improves wound healing in diabetic mice via inflammation modulation, collagen synthesis, and vascular network formation

Chronic-healing skin wounds are a common complication in diabetic individuals. To alleviate patient suffering, there is a pressing demand for more effective strategies to expedite the repair of diabetic wounds. Fibroblast growth factor 21(FGF21) has been proven to accelerate wound healing, but its stability and ability to assist in the healing of diabetic ulcers have not met expectations. Therefore, we have fused FGF21 with an elastin-like peptide (ELP) to create a recombinant fusion protein (abbreviated as "ELF") to increase the bioactivity and stability in vitro or in vivo. Our results demonstrated that ELF significantly improved the efficiency of FGF21 purification due to the inverse temperature responsive phase transition property of ELP. Meanwhile, the fusion strategy did not impair the structure of FGF21 or diminish its activity, as demonstrated by the highly similar secondary structure of ELF and FGF21, and their considerable inhibitory activity in the glucose consumption experiment of Huh-7 cells. An in vitro migration assay revealed that ELF promoted healing more effectively than either free FGF21 or ELP. Further in vivo study revealed the ability of ELF to improve skin wound healing quality, manifested by lower levels of inflammatory factors, more collagen formation and deposition, and the formation of robust vascular networks, though there was no significant difference in healing rate among the ELF, FGF21, and ELP groups. In conclusion, our study indicated that FGF21 and ELP fusion molecules could be developed as more efficient and cost-effective therapeutic strategies for diabetic wound healing.

Evaluation of Totarol for Promoting Open Wound Healing in Dogs

This study investigates the susceptibility of common pathogens to totarol and assesses its clinical effectiveness in promoting wound healing in client-owned dogs with open wounds. Twenty-three client-owned dogs with open wounds were divided into two groups: (1) the treatment group (T-group) and (2) the control group (C-group). Clinical samples were collected from the wounds for the bacterial identification and determination of the minimum inhibitory concentrations (MICs) of totarol. In the T-group, wounds were treated with standard wound care together with the application at a dosage of 0.3 mL (two sprays) of commercial totarol product per 25 cm2 of the wound area. The C-group received only standard wound care. This in vitro study found that totarol exhibited antimicrobial activity against both standard pathogens and clinical wound pathogens. The MIC values of totarol dissolved in absolute ethyl alcohol were 4 µg/mL for Gram-positive pathogens and ranged from 256 to 512 µg/mL for Gram-negative pathogens. However, the MIC values of the commercial totarol product ranged from 512 to 1024 for both Gram-positive and Gram-negative pathogens. Clinically, the use of a commercial totarol product as an adjunctive therapy significantly improved wound healing, as indicated by a greater percentage of wound area reduction (p < 0.05). From day 2 to day 7 of the treatment, the percentage of wound area reduction differed significantly between the T-group and the C-group. At the end of the study, the average percentage of wound area reduction was 69.18% ± 18.12 and 41.50% ± 20.23 in the T-group and C-group, respectively. The finding of this study illustrates the antimicrobial properties of totarol and its product against prevalent wound pathogens. These results suggest the potential of totarol as an adjunctive option for canine wound care.

Unraveling the RAGE-NF-κB pathway: implications for modulating inflammation in diabetic neuropathy through photobiomodulation therapy

Diabetic peripheral neuropathy (DPN) is a primary complication observed in diabetes that severely affects quality of life. Recent evidence suggests that photobiomodulation (PBM) is a promising therapy against painful conditions and nerve damage. However, the effects of PBM on DPN remains mostly unknown. In the present study, we investigated the efficacy of PBM therapy in modulating proinflammatory cytokine expression in both central and peripheral nervous systems of rats with Streptozotocin (STZ)-induced type 1 diabetes. Male Wistar rats were allocated into control (naïve), diabetic (STZ), and treatment (STZ + PBM) groups. A single intraperitoneal (i.p.) injection of STZ (85 mg/kg) was administered for the induction of diabetes. Animals were subjected to 10 treatment sessions, every other day. The results herein presented indicate that PBM treatment diminishes Receptor for Advanced Glycation End-products (RAGE) and Nuclear Factor Kappa B (NF-ϰB) expression in peripheral nervous system and suppresses TNF-α expression in central nervous system tissues. Furthermore, PBM-therapy in diabetic rats also induces increased levels of the anti-inflammatory protein IL-10 in both peripheral and central nervous system. Collectively, our findings demonstrate compelling evidence that PBM-therapy modulates cytokine dynamics and influences RAGE/NF-ϰB axis in a STZ-induced model of type 1 diabetes.

Effect of a portable light emitting diode device on wound healing in a rat model

Light-emitting diode (LED) lights produce a variety of wavelengths that have demonstrable efficacy in therapeutic and aesthetic fields. However, a repetitive treatment regimen is required to produce treatment outcomes, which has created a need for portable LED devices. In this study, we aimed to develop a portable therapeutic LED device and investigate its healing effect on excisional wounds in a rat model. The 35 × 35 mm-sized LED device was used on a total of 30 rats with full-thickness wounds that were divided into two groups depending on radiation intensity (11.1 and 22.2 mW/cm2 group). LED irradiation was performed every 24 h for 30 min, over 14 days, in direct contact with the wound. Percentage wound closure was measured by photographic quantification and was assessed histologically using haematoxylin and eosin (H&E) and Masson's Trichrome staining, and immunohistochemistry for Vascular endothelial growth factor (VEGF) and CD31. Percentage wound closure was significantly higher in 22.2 mW/cm2 irradiated wounds than that in the control wounds on days 7 and 10. The area of collagen deposition was remarkably larger in 22.2 mW/cm2 irradiated wounds than that in the control, with more horizontally organized fibres. CD31 immunostaining confirmed a significant increase in the number of microvessels in 22.2 mW/cm2 irradiated wounds than that in the control wounds, although there was no difference in VEGF immunostaining. Our novel portable LED device accelerates wound healing in a rat model, raising the possibility that portable LED devices can combine convenience with accessibility to play an innovative role in wound dressing.

Exploring the Safety and Efficacy of Organic Light-Emitting Diode in Skin Rejuvenation and Wound Healing

PURPOSE

Photobiomodulation (PBM), encompassing low-energy laser treatment and light-emitting diode (LED) phototherapy, has demonstrated positive impacts on skin rejuvenation and wound healing. Organic light-emitting diodes (OLEDs) present a promising advancement as wearable light sources for PBM. However, the biological and biochemical substantiation of their skin rejuvenation and wound healing effects remains limited. This study aimed to ascertain the safety and efficacy of OLEDs as a next-generation PBM modality through comprehensive in vitro and in vivo investigations.

MATERIALS AND METHODS

Cell viability assays and human ex vivo skin analyses were performed after exposure to OLED and LED irradiation to examine their safety. Subsequent evaluations examined expression levels and wound healing effects in human dermal fibroblasts (HDFs) using quantitative reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and wound healing assays post-irradiation. Additionally, an in vivo study was conducted using a ultra violet (UV)-irradiated animal skin model to explore the impact of OLED exposure on dermal collagen density and wrinkles, employing skin replica and tissue staining techniques.

RESULTS

OLED irradiation had no significant morphological effects on human skin tissue, but caused a considerably higher expression of collagen than the control and LED-treated groups. Moreover, OLED irradiation reduced the expression levels of matrix metalloproteinases (MMPs) more effectively than did LED on HDFs. OLED irradiation group in HDFs had significantly higher expression levels of growth factors compared to the control group, but similar to those in the LED irradiation group. In addition, OLED irradiation on photo-aged animal skin model resulted in increased collagen fiber density in the dermis while reducing ultra violet radiation-mediated skin wrinkles and roughness, as shown in the skin replica.

CONCLUSION

This study established comparable effectiveness between OLED and LED irradiation in upregulating collagen and growth factor expression levels while downregulating MMP levels in vitro. In the UV-irradiated animal skin model, OLED exposure post UV radiation correlated with reduced skin wrinkles and augmented dermal collagen density. Accelerated wound recovery and demonstrated safety further underscore OLEDs' potential as a future PBM modality alongside LEDs, offering promise in the realms of skin rejuvenation and wound healing.

Microbiota-derived imidazole propionate inhibits type 2 diabetic skin wound healing by targeting SPNS2-mediated S1P transport

Imidazole propionate (ImP) is a recently discovered metabolite of T2DM-related gut microbiota. The effect of ImP on T2DM wound healing has not been studied yet. In this research, the changes of ImP-producing bacteria on the skin are firstly evaluated. 16sRNA sequencing results showed that the abundance of ImP-producing bacteria-Streptococcus in the intestine and skin of T2DM mice is significantly increased. Animal experiments show that ImP can inhibit the process of wound healing and inhibit the formation of blood vessels in the process of wound healing. Molecular mechanism research results show that ImP can inhibit S1P secretion mediated by SPNS2, and inhibit the activation of Rho signaling pathway, thereby affecting the angiogenesis process of HUVEC cells. This work also provides a potential drug HMPA that promotes T2DM wound healing.

Enhancing viability and angiogenic efficacy of mesenchymal stem cells via HSP90α and HSP27 regulation based on ROS stimulation for wound healing

Light-based therapy has been reported as a potential preconditioning strategy to induce intracellular reactive oxygen species (ROS) signaling and improve the angiogenic properties of various types of cells. However, bio-stimulation mechanisms of light therapy in terms of ROS-heat shock proteins (HSPs) mediated anti-apoptotic and angiogenic pathways in human adult stem cells have not been fully delineated yet. Commonly used light sources such as light-emitting diode (LED) and laser are accompanied by drawbacks, such as phototoxicity, thermal damage, and excessive ROS induction, so the role and clinical implications of light-induced HSPs need to be investigated using a heat-independent light source. Here, we introduced organic LED (OLED) at 610 nm wavelength as a new light source to prevent thermal effects from interfering with the expression of HSPs. Our results showed that light therapy using OLED significantly upregulated anti-apoptotic and angiogenic factors in human bone marrow mesenchymal stem cells (hMSCs) at both gene and protein levels via the activation of HSP90α and HSP27, which were stimulated by ROS. In a mouse wound-closing model, rapid recovery and improved re-epithelization were observed in the light-treated hMSCs transplant group. This study demonstrates that the upregulation of Akt (protein kinase B)-nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling, caused by HSP90α and HSP27 expression, is the mechanism behind the anti-apoptotic and angiogenic effects of OLED treatment on stem cells.

Diabetic foot ulcer: Challenges and future

Diabetic foot ulcers (DFUs) have become one of the important causes of mortality and morbidity in patients with diabetes, and they are also a common cause of hospitalization, which places a heavy burden on patients and society. The prevention and treatment of DFUs requires multidisciplinary management. By controlling various risk factors, such as blood glucose levels, blood pressure, lipid levels and smoking cessation, local management of DFUs should be strengthened, such as debridement, dressing, revascularization, stem cell decompression and oxygen therapy. If necessary, systemic anti-infection treatment should be administered. We reviewed the progress in the clinical practice of treating DFUs in recent years, such as revascularization, wound repair, offloading, stem cell transplantation, and anti-infection treatment. We also summarized and prospectively analyzed some new technologies and measurements used in the treatment of DFUs and noted the future challenges and directions for the development of DFU treatments.

Impact of photobiomodulation on macrophages and their polarization during diabetic wound healing: a systematic review

This review aims to providing essential information and the current knowledge about the potential role of macrophages, especially their M2 subtypes in different diabetic wounds both in clinical and pre-clinical models under the influence of photobiomodulation (PBM). The long-term goal is to advance the macrophage-based therapies to accelerate healing of diabetic foot ulcers. We reviewed all databases provided by PubMed, Google Scholar, Scopus, Web of Science, and Cochrane precisely from their dates of inception to 25/10/2021. The keywords of Diabetes mellitus diseases, wound healing, macrophage, and photobiomodulation or low-level laser therapy were used in this systematic review.A total of 438 articles were initially identified in pubmed.ncbi.nlm.nih.gov (15 articles), Google scholar (398 articles), Scopus (18 articles), and Web of Science (7 articles). Four hundred sixteen articles that remained after duplicate studies (22 articles) were excluded. After screening abstracts and full texts, 14 articles were included in our analysis. Among them, 4 articles were about the effect of PBM on macrophages in type 2 diabetes and also found 10 articles about the impact of PBM on macrophages in type 1 diabetes. The obtained data from most of the reviewed studies affirmed that the PBM alone or combined with other agents (e.g., stem cells) could moderate the inflammatory response and accelerate the wound healing process in pre-clinical diabetic wound models. However, only very few studies conducted the detailed functions of polarized macrophages and M2 subtypes in wound healing of diabetic models under the influence of PBM. Further pre-clinical and clinical investigations are still needed to investigate the role of M2 macrophages, especially its M2c subtype, in the healing processes of diabetic foot ulcers in clinical and preclinical settings.

Evaluation of the red & blue LED effects on cutaneous refractory wound healing in male Sprague-Dawley rat using 3 different multi-drug resistant bacteria

OBJECTIVES

Photobiomodulation (PBM) is widely used in clinical therapy, and is an effective approach to resist the bacterial infection of the cutaneous wound and modulate the wound healing process. Due to the several detriments of lasers, Red & Blue LED light (RBLL) may be a more viable light source. This study is aimed to evaluate and compare the therapeutic effect of RBLL light on different multi-drug resistant (MDR) bacteria in vitro and male Sprague-Dawley (SD) rat refractory MDR infection wound model in vivo.

MATERIALS AND METHODS

Methicillin-resistant Staphylococcus aureus (MRSA), Extended-spectrum β-lactamases -producing Escherichia coli (ESBLs-Eco), and the MDR Pseudomonas aeruginosa (MDR-Pae) were employed to evaluate the antibacterial effects of the Blue LED light in vitro. Effects of RBLL on in vivo wound healing were evaluated by analyzing time to closure, wound score, semi-quantitative test for bacterial culture, histopathological examination and Masson staining of skin tissue, immunohistochemical (IHC) staining, and western blot analysis (WB) of wound tissue.

RESULTS

Blue LED light inhibited MRSA, ESBLs-Eco, and MDR-Pae in vitro study. In vivo, RBLL accelerated wound healing, reduced levels of pathogenic bacteria on the wound surface while increasing the blood supply to the wound surface and inhibiting the excessive inflammatory response.

CONCLUSION

RBLL showed a great potential gain for the treatment of MDR bacterial infected wounds, suggesting PBM therapy is an inexpensive, convenient, pain-free, and safe therapeutic intervention for refractory MDR infection wounds.

Area light source-triggered latent angiogenic molecular mechanisms intensify therapeutic efficacy of adult stem cells

Light-based therapy such as photobiomodulation (PBM) reportedly produces beneficial physiological effects in cells and tissues. However, most reports have focused on the immediate and instant effects of light. Considering the physiological effects of natural light exposure in living organisms, the latent reaction period after irradiation should be deliberated. In contrast to previous reports, we examined the latent reaction period after light exposure with optimized irradiating parameters and validated novel therapeutic molecular mechanisms for the first time. we demonstrated an organic light-emitting diode (OLED)-based PBM (OPBM) strategy that enhances the angiogenic efficacy of human adipose-derived stem cells (hADSCs) via direct irradiation with red OLEDs of optimized wavelength, voltage, current, luminance, and duration, and investigated the underlying molecular mechanisms. Our results revealed that the angiogenic paracrine effect, viability, and adhesion of hADSCs were significantly intensified by our OPBM strategy. Following OPBM treatment, significant changes were observed in HIF-1α expression, intracellular reactive oxygen species levels, activation of the receptor tyrosine kinase, and glycolytic pathways in hADSCs. In addition, transplantation of OLED-irradiated hADSCs resulted in significantly enhanced limb salvage ratio in a mouse model of hindlimb ischemia. Our OPBM might serve as a new paradigm for stem cell culture systems to develop cell-based therapies in the future.

Assessment of wound area reduction on chronic wounds in dogs with photobiomodulation therapy: A randomized controlled clinical trial

Background and Aim

Chronic wounds are a clinical problem and require intensive standard wound care. However, this is sometimes insufficient to promote healing. Photobiomodulation therapy (PBMT) can be used as an adjunctive therapy to improve wound healing. Various PBMT devices with different properties and parameter settings as well as different animal species can influence a variety of clinical outcomes. This study aims to assess the use of 830 nm PBMT or simultaneous superpulsed and multiple wavelengths (SPMW; 660, 875, and 905 nm) PBMT on chronic wounds in client-owned dogs.

Materials and Methods

This study included 21 client-owned dogs with chronic wounds allocated into three groups: (1) Control group (C) treated with irrigated saline and without PBMT (n=7); (2) L1 group treated with irrigated saline together with the radiation of 830 nm PBMT (n=7); and (3) L2 group treated with irrigated saline together with the radiation of simultaneous SPMW-PBMT (n=7). Wound healing was assessed on the basis of wound size reduction as a percentage of wound area every 2^nd day for 15 days using image analysis software (ImageJ software^®, National Institutes of Health, Rockville, Maryland, USA).

Results

A significant difference in the percentage of wound area reduction was noted between the C and PBMT groups (L1 and L2; p<0.05). The average percentages of wound area reduction at the end of the study (15 days) were 42.39±20.58, 56.98±24.82, and 61.81±27.18 in the C, L1, and L2 groups, respectively. A steady decrease in wound size was noted in both PBMT and non-PBMT groups, and coefficients were 7.77, 8.95, and 10.01 in the C, L1, and L2 groups, respectively. The percentage of wound area reduction was found to be significantly different between the PBMT and non-BPMT groups on day 7 (p<0.05).

Conclusion

Based on the results of the current study, using either 830 nm PBMT or simultaneous SPMW-PBMT can accelerate the chronic wound healing process in dogs with a significant reduction in wound area. Therefore, it can be used as an adjunctive therapy to improve wound healing in dogs with reduced treatment duration.

Lightwave-reinforced stem cells with enhanced wound healing efficacy

Comprehensive research has led to significant preclinical outcomes in modified human adipose-derived mesenchymal stem cells (hADSCs). Photobiomodulation (PBM), a technique to enhance the cellular capacity of stem cells, has attracted considerable attention owing to its effectiveness and safety. Here, we suggest a red organic light-emitting diode (OLED)-based PBM strategy to augment the therapeutic efficacy of hADSCs. In vitro assessments revealed that hADSCs basked in red OLED light exhibited enhanced angiogenesis, cell adhesion, and migration compared to naïve hADSCs. We demonstrated that the enhancement of cellular capacity was due to an increased level of intracellular reactive oxygen species. Furthermore, accelerated healing and regulated inflammatory response was observed in mice transplanted with red light-basked hADSCs. Overall, our findings suggest that OLED-based PBM may be an easily accessible and attractive approach for tissue regeneration that can be applied to various clinical stem cell therapies.

Photodynamic Therapy Delays Cutaneous Wound Healing in Mice

BACKGROUND

Cutaneous wound healing is a complex, dynamic physiological process. Traditional methods of promoting wound healing are not always effective. Consequently, alternative modalities, such as photodynamic therapy (PDT), are needed. We examined the effectiveness and underlying mechanisms of PDT in a murine model of acute wound healing.

METHODS

Two excisional wounds were produced, one on each side of the midline, in C57bL/6J mice. Methyl 5-aminolevulinate hydrochloride (MAL) was applied to the right-side wound. After 1 to 3 hours of incubation, the wound was irradiated with red light. The left-side wound was not treated with MAL or red light. On Day 14, the wounds were excised and subjected to histological and immunohistochemical analysis.

RESULTS

During the first week, no difference was seen between the two sides. However, at week 2, PDT-treated wounds exhibited delayed re-epithelialization. On Day 14, hematoxylin and eosin (HE) staining showed a continuous epithelial lining in untreated wounds. In contrast, PDT-treated wounds partially lacked epithelium in the wound bed. Masson's Trichrome (MTC) staining showed a thicker dermis and more collagen fibers and inflammatory cells in PDT-treated wounds than in untreated wounds. Immunohistochemical analyses showed significantly fewer CD31⁺ blood vessels and greater collagen III density in PDT-treated wounds than in untreated wounds. However, treated and untreated wounds did not differ in collagen I density.

CONCLUSIONS

PDT delayed acute wound healing in a murine model of secondary intention wound healing.

Organic Light-Emitting Diodes: Pushing Toward the Limits and Beyond

Organic light-emitting diodes (OLEDs) are established as a mainstream light source for display applications and can now be found in a plethora of consumer electronic devices used daily. This success can be attributed to the rich luminescent properties of organic materials, but efficiency enhancement made over the last few decades has also played a significant role in making OLEDs a practically viable technology. This report summarizes the efforts made so far to improve the external quantum efficiency (EQE) of OLEDs and discusses what should further be done to push toward the ultimate efficiency that can be offered by OLEDs. The study indicates that EQE close to 58% and 80% can be within reach without and with additional light extraction structures, respectively, with an optimal combination of cavity engineering, low-index transport layers, and horizontal dipole orientation. In addition, recent endeavors to identify possible applications of OLEDs beyond displays are presented with emphasis on their potential in wearable healthcare, such as OLED-based pulse oximetry as well as phototherapeutic applications based on body-attachable flexible OLED patches. OLEDs with fabric-like form factors and washable encapsulation strategies are also introduced as technologies essential to the success of OLED-based wearable electronics.

Is 640 nm high-fluence visible red light a valuable adjunct for treating pemphigus vegetans? A single case report

BACKGROUND

Pemphigus vegetans is an autoimmune bullous disorder characterized by vegetating lesions commonly over the flexures. This disorder is characterized by vegetating lesions more commonly over flexures. Cerebriform tongue, a morphology with typical pattern of sulci and gyri over dorsum of the tongue, is a well-known sign seen in pemphigus vegetans.

AIMS

To emphasize the exceptional but successful use of corticosteroid and 640 nm high-fluence visible red light in pemphigus vegetans.

METHODS

The patient was successfully treated with low dose systemic corticosteroid (methylprednisolone 20 mg daily) and high-fluence 640 nm LED red light on pustules and exudates (LIFOTRONICR, 120 mw/cm² power density and 210 J/cm² energy density).

RESULTS

The cerebriform plaques improved quickly after the treatment of corticosteroid and 640 nm high-fluence visible red light.

CONCLUSION

We propose to consider low dosage of methylprednisolone and 640 nm high fluence visible red light as first-line monotherapy in pemphigus vegetans, especially in elderly patients with comorbidities and contraindications to standard therapy, as it avoids the toxicities of systemic corticosteroids and immunosuppressants.

Improvement of full-thickness rat skin wounds by photobiomodulation therapy (PBMT): A dosimetric study

Basic dosimetric studies are necessary to support the use of photobiomodulation therapy (PBMT), since the great variety of laser parameters that are reported in the literature have created an obstacle to identifying reproducible results. Thus, the present study evaluates the process of tissue repair after the photobiomodulation therapy, taking into consideration the dose, frequency and the mode of energy delivery used. For this, 6 mm diameter wounds were created on dorsal skin of Wistar rats, and the animals were divided in control and irradiated groups, where L1 and L4 (irradiated with 1 point of 10 J/cm2), L2 and L5 (5 points of 10 J/cm2), L3 and L6 (1 point of 50 J/cm2), respectively for one or multiple days of irradiations. A diode laser, λ 660 nm, 40 mW of power and 0.028 cm2 of spot area was used. Our data showed that the group receiving multiple treatments over the first week post wounding, applied at 10 J/cm2 at each of 5 points on and around the wound (group L5) presented the best improvement of wound closure, higher cytokeratin 10, lower macrophage infiltration, and greater tissue resistance to rupture. We conclude that PBMT improves the skin wound healing process, and the outcomes were directly related to the chosen laser parameters and irradiation mode.

Recent Progress of Fiber Shaped Lighting Devices for Smart Display Applications-A Fibertronic Perspective

Advances in material science and nanotechnology have fostered the miniaturization of devices. Over the past two decades, the form-factor of these devices has evolved from 3D rigid, volumetric devices through 2D film-based flexible electronics, finally to 1D fiber electronics (fibertronics). In this regard, fibertronic strategies toward wearable applications (e.g., electronic textiles (e-textiles)) have attracted considerable attention thanks to their capability to impart various functions into textiles with retaining textiles' intrinsic properties as well as imperceptible irritation by foreign matters. In recent years, extensive research has been carried out to develop various functional devices in the fiber form. Among various features, lighting and display features are the highly desirable functions in wearable electronics. This article discusses the recent progress of materials, architectural designs, and new fabrication technologies of fiber-shaped lighting devices and the current challenges corresponding to each device's operating mechanism. Moreover, opportunities and applications that the revolutionary convergence between the state-of-the-art fibertronic technology and age-long textile industry will bring in the future are also discussed.

Sandwich-structure transferable free-form OLEDs for wearable and disposable skin wound photomedicine

Free-form optoelectronic devices can provide hyper-connectivity over space and time. However, most conformable optoelectronic devices can only be fabricated on flat polymeric materials using low-temperature processes, limiting their application and forms. This paper presents free-form optoelectronic devices that are not dependent on the shape or material. For medical applications, the transferable OLED (10 μm) is formed in a sandwich structure with an ultra-thin transferable barrier (4.8 μm). The results showed that the fabricated sandwich-structure transferable OLED (STOLED) exhibit the same high-efficiency performance on cylindrical-shaped materials and on materials such as textile and paper. Because the neutral axis is freely adjustable using the sandwich structure, the textile-based OLED achieved both folding reliability and washing reliability, as well as a long operating life (>150 h). When keratinocytes were irradiated with red STOLED light, cell proliferation and cell migration increased by 26 and 32%, respectively. In the skin equivalent model, the epidermis thickness was increased by 39%; additionally, in organ culture, not only was the skin area increased by 14%, but also, re-epithelialization was highly induced. Based on the results, the STOLED is expected to be applicable in various wearable and disposable photomedical devices.

Heparin-poloxamer hydrogel-encapsulated rhFGF21 enhances wound healing in diabetic mice

Wound healing, especially for diabetic wounds, is a lengthy and complicated process involving interactions and responses at the protein, cell, and tissue levels. Loading of growth factors into a hydrogel to construct a sustained-release system is considered a promising approach to improve wound healing. The present study investigates the effect of thermosensitive heparin-poloxamer (HP) hydrogel-encapsulated recombinant human fibroblast growth factor 21 (rhFGF21) on wound healing in mice with streptozotocin-induced diabetes mellitus. First, we studied the in vitro release of rhFGF21 from the rhFGF21-HP coacervate. The results showed that HP might control the release of rhFGF21. Next, we examined the effect of rhFGF21-HP on skin wound healing in diabetic mice. Our data showed that rhFGF21-HP significantly improved wound closure; promoted granulation, collagen deposition, and re-epithelialization; and enhanced the expression of CD31. Moreover, rhFGF21-HP had obvious advantages in diabetic wound healing. Therefore, the results suggest that the rhFGF21-HP hydrogel polymer plays an important role in skin wound healing. This work provides a suitable sustained-release delivery system that can continuously release rhFGF21 and presents a promising therapeutic strategy for wound healing in patients with diabetes.-Liu, H., Zhao, Y., Zou, Y., Huang, W., Zhu, L., Liu, F., Wang, D., Guo, K., Hu, J., Chen, J., Ye, L., Li, X., Lin, L. Heparin-poloxamer hydrogel-encapsulated rhFGF21 enhances wound healing in diabetic mice.

Efficacy of Biophysical Energies on Healing of Diabetic Skin Wounds in Cell Studies and Animal Experimental Models: A Systematic Review

We have systematically assessed published cell studies and animal experimental reports on the efficacy of selected biophysical energies (BPEs) in the treatment of diabetic foot ulcers. These BPEs include electrical stimulation (ES), pulsed electromagnetic field (PEMF), extracorporeal shockwave (ECSW), photo energies and ultrasound (US). Databases searched included CINAHL, MEDLINE and PubMed from 1966 to 2018. Studies reviewed include animal and cell studies on treatment with BPEs compared with sham, control or other BPEs. Information regarding the objective measures of tissue healing and data was extracted. Eighty-two studies were eventually selected for the critical appraisal: five on PEMF, four each on ES and ECSW, sixty-six for photo energies, and three about US. Based on the percentage of original wound size affected by the BPEs, both PEMF and low-level laser therapy (LLL) demonstrated a significant clinical benefit compared to the control or sham treatment, whereas the effect of US did not reveal a significance. Our results indicate potential benefits of selected BPEs in diabetic wound management. However, due to the heterogeneity of the current clinical trials, comprehensive studies using well-designed trials are warranted to confirm the results.

Photobiomodulation with red light-emitting diodes accelerates hepatocyte proliferation through reactive oxygen species/extracellular signal-regulated kinase pathway

AIM

Cell-based transplantation is an alternate method of liver transplantation to delay the onset of end-stage liver diseases. For successful treatment, cells need to be expended in vitro expeditiously. However, autogenetic hepatocytes as the ideal cell source for therapy remain in quiescence so proliferation is rare. Photobiomodulation therapy has been used to stimulate some kinds of cell proliferation, but is unknown whether red light-emitting diode (LED) irradiation can promote primary hepatocyte proliferation. The aim of this study was to evaluate the effect of red LED irradiation on hepatocytes in vitro.

METHODS

Mouse primary hepatocytes were isolated and received red LED treatment. The cell viability, reactive oxygen species (ROS) levels, phosphorylated extracellular signal-regulated kinase1/2 (pERK1/2) and some cell cycle-related proteins were observed. Additionally, ROS inhibition and pERK1/2 inhibition were carried out to determine the effect of ROS and ERK1/2 in red LED irradiation.

RESULTS

The red LED irradiation increased hepatocyte proliferation, elevated intracellular ROS levels, and stimulated ERK1/2 activation and cell cycle-related gene expression. The mitosis promoting effect of red LED irradiation could be disturbed by ROS or pERK inhibition. The red LED irradiation promoted hepatocyte proliferation through the ROS/pERK1/2 pathway.

CONCLUSIONS

Red LED irradiation could accelerate hepatocyte proliferation through the ROS/pERK1/2 pathway. Red LED irradiation might be a potential method to increase hepatocyte cell numbers in vitro and support cell-based transplantation in clinical work.

Photobiomodulation: lasers vs. light emitting diodes?

Photobiomodulation (PBM) is a treatment method based on research findings showing that irradiation with certain wavelengths of red or near-infrared light has been shown to produce a range of physiological effects in cells, tissues, animals and humans. Scientific research into PBM was initially started in the late 1960s by utilizing the newly invented (1960) lasers, and the therapy rapidly became known as "low-level laser therapy". It was mainly used for wound healing and reduction of pain and inflammation. Despite other light sources being available during the first 40 years of PBM research, lasers remained by far the most commonly employed device, and in fact, some authors insisted that lasers were essential to the therapeutic benefit. Collimated, coherent, highly monochromatic beams with the possibility of high power densities were considered preferable. However in recent years, non-coherent light sources such as light-emitting diodes (LEDs) and broad-band lamps have become common. Advantages of LEDs include no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, possibility of wearable devices, and much lower cost per mW. LED photobiomodulation is here to stay.

Photobiomodulation: lasers vs. light emitting diodes?

Photobiomodulation (PBM) is a treatment method based on research findings showing that irradiation with certain wavelengths of red or near-infrared light has been shown to produce a range of physiological effects in cells, tissues, animals and humans. Scientific research into PBM was initially started in the late 1960s by utilizing the newly invented (1960) lasers, and the therapy rapidly became known as "low-level laser therapy". It was mainly used for wound healing and reduction of pain and inflammation. Despite other light sources being available during the first 40 years of PBM research, lasers remained by far the most commonly employed device, and in fact, some authors insisted that lasers were essential to the therapeutic benefit. Collimated, coherent, highly monochromatic beams with the possibility of high power densities were considered preferable. However in recent years, non-coherent light sources such as light-emitting diodes (LEDs) and broad-band lamps have become common. Advantages of LEDs include no laser safety considerations, ease of home use, ability to irradiate a large area of tissue at once, possibility of wearable devices, and much lower cost per mW. LED photobiomodulation is here to stay.

Flexible quantum dot light-emitting devices for targeted photomedical applications

Quantum dot light-emitting devices (QLEDs), originally developed for displays, were recently demonstrated to be promising light sources for various photomedical applications, including photodynamic therapy cancer cell treatment and photobimodulation cell metabolism enhancement. With exceptional emission wavelength tunability and potential flexibility, QLEDs could enable wearable, targeted photomedicine with maximized absorption of different medical photosensitizers. In this paper, we report, for the first time, the in vitro study to demonstrate that QLEDs-based photodynamic therapy can effectively kill Methicillin-resistant Staphylococcus aureus, an antibiotic-resistant bacterium. We then present successful synthesis of highly efficient quantum dots with narrow spectra and specific peak wavelengths to match the absorption peaks of different photosensitizers for targeted photomedicine. Flexible QLEDs with a peak external quantum efficiency of 8.2% and a luminance of over 20,000 cd/m² at a low driving voltage of 6 V were achieved. The tunable, flexible QLEDs could be employed for oral cancer treatment or diabetic wound repairs in the near future. These results represent one fresh stride toward realizing QLEDs' long-term goal to enable the wide clinical adoption of photomedicine.

Toward Efficient and Metal-Free Emissive Devices: A Solution-Processed Host-Guest Light-Emitting Electrochemical Cell Featuring Thermally Activated Delayed Fluorescence

The next generation of emissive devices should preferably be efficient, low-cost, and environmentally sustainable, and as such utilize all electrically generated excitons (both singlets and triplets) for the light emission, while being free from rare metals such as iridium. Here, we report on a step toward this vision through the design, fabrication, and operation of a host-guest light-emitting electrochemical cell (LEC) featuring an organic thermally activated delayed fluorescence (TADF) guest that harvests both singlet and triplet excitons for the emission. The rare-metal-free active material also consists of a polymeric electrolyte and a polymeric compatibilizer for the facilitation of a cost-efficient and scalable solution-based fabrication, and for the use of air-stable electrodes. We report that such TADF-LEC devices can deliver uniform green light emission with a maximum luminance of 228 cd m^-2 when driven by a constant-current density of 770 A m^-2, and 760 cd m^-2 during a voltage ramp, which represents a one-order-of-magnitude improvement in comparison to previous TADF-emitting LECs.

Noninvasive red and near-infrared wavelength-induced photobiomodulation: promoting impaired cutaneous wound healing

The innumerable intricacies associated with chronic wounds have made the development of new painless, noninvasive, biophysical therapeutic interventions as the focus of current biomedical research. Red and near-infrared light-induced photobiomodulation therapy appears to emerge as a promising drug-free approach for promoting wound healing, reduction in inflammation, pain and restoration of function owing to penetration power in conjunction with their ability to positively modulate the biochemical and molecular responses. This review will describe the physical properties of red and near-infrared light and their interaction with skin and highlight their efficacy of wound repair and regeneration. Near-infrared (800-830 nm) was found to be the most effective and widely studied wavelength range followed by red (630-680 nm) and 904 nm superpulsed light exhibiting beneficial photobiomodulatory effects on impaired dermal wound healing.

The effect of combined photobiomodulation and metformin on open skin wound healing in a non-genetic model of type II diabetes

This study intended to examine the combined influences of photobiomodulation (PBM) and metformin on the microbial flora and biomechanical parameters of wounds in a non-genetic model of type II diabetes mellitus (TII DM). We induced a non-genetic model of TII DM in 20 rats by feeding them a 10% fructose solution for 2weeks followed by an injection of streptozotocin (STZ, 40mg/kg). After 21days from the injection of STZ, we induced one full-thickness skin wound in each of the diabetic rats. We randomly divided the rats into four groups: i) placebo; ii) pulsed wave laser (890nm, 80Hz, 0.324J/cm²); iii) metformin; and iv) laser+metformin. Rats received daily intraperitoneal injections of metformin (50mg/kg). On days 7and 15 we inspected the microbial flora of each wound. On day 15 we obtained a standard sample from each healing wound for biomechanical analyses. PBM significantly decreased colony-forming units (CFUs) 7days after wound infliction compared to the placebo group (LSD test, p=0.012). Metformin significantly enhanced the biomechanical property (stress high load) of the wounds compared to the placebo group (LSD test, p=0.028). We observed the same significant result for PBM compared to the placebo group (LSD test, p=0.047). PBM significantly accelerated the wound healing process and significantly reduced CFUs of bacteria in a non-genetic rat model of TII DM.

Use of Adipose-Derived Stem Cells to Support Topical Skin Adhesive for Wound Closure: A Preliminary Report from Animal In Vivo Study

The aim of this study was to determine the local and systemic effects of adipose-derived stem cells (ADSCs) as a component of topical skin adhesive in an animal artificial wound closure model. In presented study the cosmetic effects, histological analysis, mechanical properties, and cell migration have been assessed to evaluate the usefulness of ADSCs as supporting factor for octyl blend cyanoacrylate adhesive. The total of 40 rats were used and divided into six groups. In the Study Group, ADSCs were administered by multipoint injection of the six surrounding intrawound areas with additional freely leaving procedure of the cells between the skin flaps just before applying adhesive to close the wound. Five control groups without using ADSCs, utilizing different types of standard wound closure, were created in order to check efficiency of experimental stem cell therapy. In our study, we proved that ADSCs could be used effectively also as a supportive tool in topical skin adhesive for wound closure. However we did not achieve any spectacular differences related to such aspects as better mechanical properties or special biological breakthroughs in wound healing properties. The use of stem cells, especially ADSCs for wound closure can provide an inspiring development in plastic and dermatologic surgery.

Restoration of Nrf2 Signaling Normalizes the Regenerative Niche

Chronic hyperglycemia impairs intracellular redox homeostasis and contributes to impaired diabetic tissue regeneration. The Keap1/Nrf2 pathway is a critical regulator of the endogenous antioxidant response system, and its dysfunction has been implicated in numerous pathologies. Here we characterize the effect of chronic hyperglycemia on Nrf2 signaling within a diabetic cutaneous regeneration model. We characterized the effects of chronic hyperglycemia on the Keap1/Nrf2 pathway within models of diabetic cutaneous wound regeneration. We assessed reactive oxygen species (ROS) production and antioxidant gene expression following alterations in the Nrf2 suppressor Keap1 and the subsequent changes in Nrf2 signaling. We also developed a topical small interfering RNA (siRNA)-based therapy to restore redox homeostasis within diabetic wounds. Western blotting demonstrated that chronic hyperglycemia-associated oxidative stress inhibits nuclear translocation of Nrf2 and impairs activation of antioxidant genes, thus contributing to ROS accumulation. Keap1 inhibition increased Nrf2 nuclear translocation, increased antioxidant gene expression, and reduced ROS production to normoglycemic levels, both in vitro and in vivo. Topical siKeap1 therapy resulted in improved regenerative capacity of diabetic wounds and accelerated closure. We report that chronic hyperglycemia weakens the endogenous antioxidant response, and the consequences of this defect are manifested by intracellular redox dysregulation, which can be restored by Keap1 inhibition. Targeted siRNA-based therapy represents a novel, efficacious strategy to reestablish redox homeostasis and accelerate diabetic cutaneous tissue regeneration.

Development of a novel sodium fusidate-loaded triple polymer hydrogel wound dressing: Mechanical properties and effects on wound repair

To develop a novel sodium fusidate-loaded triple polymer hydrogel dressing (TPHD), numerious polyvinyl alcohol-based (PVA) hydrogel dressings were prepared with various hydrophilic polymers using the freeze-thaw method, and their hydrogel dressing properties were assessed. Among the hydrophilic polymers tested, sodium alginate (SA) improved the swelling capacity the most, and polyvinyl pyrrolidone (PVP) provided the greatest improvement in bioadhesive stength and mechanical properties. Thus, PVA based-TPHDs were prepared using different ratios of PVP:SA. The effect of selected PVP:SA ratios on the swelling capacity, bioadhesive strength, mechanical properties, and drug release, permeation and deposition characteristics of sodium fusidate-loaded PVA-based TPHDs were assessed. As the ratio of PVP:SA increased in PVA-loaded TPHD, the swelling capacity, mechanical properties, drug release, permeation and deposition were improved. The TPHD containing PVA, PVP, SA and sodium fusidate at the weight ratio of 10/6/1/1 showed excellent hydrogel dressing properties, release, permeation and deposition of drug. Within 24h, 71.8 ± 1.3% of drug was released. It permeated 625.1 ± 81.2 μg/cm(2) through the skin and deposited of 313.8 ± 24.1 μg/cm(2) within 24h. The results of in vivo pharmacodynamic studies showed that sodium fusidate-loaded TPHD was more effective in improving the repair process than was a commercial product. Thus, this sodium fusidate-loaded TPHD could be a novel tool in wound care.

Novel neomycin sulfate-loaded hydrogel dressing with enhanced physical dressing properties and wound-curing effect

To develop a novel neomycin sulfate-loaded hydrogel dressing (HD), numerous neomycin sulfate-loaded HDs were prepared with various amounts of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) and sodium alginate (SA) using freeze-thawing technique, and their physical dressing properties, drug release, in vivo wound curing and histopathology in diabetic-induced rats were assessed. SA had a positive effect on a swelling capacity, but a negative effect on the physical dressing properties and drug release of HD. However, PVP did the opposite. In particular, the neomycin sulfate-loaded HD composed of drug, PVA, PVP and SA at the weight ratio of 1/10/0.8/0.8 had excellent swelling and bioadhesive capacity, good elasticity and fast drug release. Moreover, this HD gave more improved wound curing effect compared to the commercial product, ensured the disappearance of granulation tissue and recovered the wound tissue to normal. Therefore, this novel neomycin sulfate-loaded HD could be an effective pharmaceutical product for the treatment of wounds.