Large-Scale Nanofiber Manufacturing| A Safe, Stable, Simple, Serviceable, and Self-Powered WoundDressing With continuous Low-Voltage Direct CurrentElectrical Stimulation: an Efficient Approach to AccelerateWound Healing

Prof. Yu Hui et al. from Wuyi University AFM: Safe, Stable, Simple, Serviceable, and Self-Powered Wound Dressing Accelerates Wound Healing

In this era of rapid technological advancement, scientific achievements continue to bring surprises and changes to our lives. Recently, a research breakthrough in wound dressings has attracted widespread attention, bringing new hope to the field of chronic wound care. Today, let's take an in-depth look at this remarkable invention - a safe, stable, simple, durable, and self-powered wound dressing.

Prof. Yu Hui and Dr. Wang Lihuan's team from Wuyi University developed a safe, stable, simple, serviceable, and self-powered (5S) ES dressing composed of an electrospun asymmetric nanofiber membrane (with screen-printed electrodes) and polyurethane foam. The asymmetric nanofiber membrane generates electricity through the electrical double layer effect during unidirectional exudate transfer, while the polyurethane foam effectively manages the exudate. This 5S dressing can produce continuous low-voltage direct current electrical stimulation at the wound site, creating an optimal microenvironment for wound epithelialization.

In vitro and in vivo studies demonstrated that it significantly promotes wound healing. Compared to the control group (day 7), the 5S dressing treatment group showed 15.9% increased collagen deposition, 90.6% higher capillary density, 228.3% greater epidermal thickness, and 23.6% improved wound healing rate, providing an efficient treatment approach for accelerated wound healing.

The related findings were published in Advanced Functional Materials under the title "A Safe, Stable, Simple, Serviceable, and Self-Powered Wound Dressing With Continuous Low-Voltage Direct Current Electrical Stimulation: an Efficient Approach to Accelerate Wound Healing". The first author is Shi Chenxi, a master's student at Wuyi University, with corresponding authors Prof. Yu Hui and Dr. Wang Lihuan from Wuyi University. Collaborators include Wang Huan (R&D Director at Winner Medical Co., Ltd.), Dr. Wang Jing (Chief Physician at Jiangmen Central Hospital), Associate Prof. Li Kefeng from Macao Polytechnic University, and Dr. Liu Pengbi from Wuyi University.

The dressing was prepared through electrospinning and screen-printing technologies, consisting of an asymmetric nanofiber membrane (PGP), electrodes (E-PGP), and polyurethane foam. In wound care, it not only drains exudate and maintains a moist healing environment but also generates streaming potential through the graphene oxide (GO) concentration gradient in the nanofiber membrane for electrical stimulation. This stimulation promotes fibroblast migration and filopodia extension, increases collagen deposition and angiogenesis, thereby facilitating wound healing.

Figure 1. Schematic diagram of P-E-PGP dressing preparation, self-powering mechanism and wound healing promotion mechanism.

Information about the microstructure, pore size distribution, diameter distribution, elemental composition, hydrophobicity, and mechanical properties of related materials in P-E-PGP dressing:Microstructure: Figure a shows the SEM image of the PAN-GO top layer containing graphene oxide, figure b shows the SEM image of the PCL bottom layer, and figure f shows the schematic diagram of the composite structure and cross-sectional SEM image.Pore size and diameter distribution: Figure c compares the pore size distribution of PAN-GO and PCL, while figures d and e show the diameter distribution and average diameter data of PAN-GO and PCL respectively.Elemental composition: Figure g displays the atomic percentages of carbon (C) and nitrogen (N) at different locations (S1-S4).Hydrophobicity: Figure h shows the water droplet contact time changes on the hydrophobic side of PAN-GO/PCL composites with different ratios, reflecting differences in hydrophobicity.Mechanical properties: Figure i presents the stress-strain curves of PAN-GO/PCL composites with different ratios, reflecting their mechanical characteristics.

Figure 2 shows the morphology, water permeability and mechanical properties of PGP membrane, as well as the N and C ratios at different cross-sectional positions of PGP membrane.

Reliable self-powering performance: A highlight of this dressing is its self-powering capability. During exudate absorption, due to the zeta potentials of -36.6 mV (PCL side) and -29.3 mV (PAN-GO side), the asymmetric nanofiber membrane attracts numerous positively charged ions (Na+, K+). Meanwhile, the gradient wettability and gradient pore structure design enable continuous transport of wound exudate within the nanofiber membrane, forming a cation concentration gradient perpendicular to the nanopores. Based on the electrical double layer effect, a potential difference forms between both sides of the fiber membrane. Experiments verify that stable voltage output can be generated when continuously dripping solution onto the PCL side of E-PGP membrane. Adding GO can further increase the voltage, with optimal effect at 0.5 wt.% GO concentration. Moreover, the E-PGP membrane can continuously generate 65 mV to 135 mV DC voltage for 12 hours, with simulation results showing it can form a radial microelectric field similar to endogenous electric fields, providing stable electrical stimulation for wound healing.

Remarkable wound healing effects: The P-E-PGP dressing significantly promotes wound healing. In vitro cell experiments demonstrate its good cytocompatibility, with L929 cells stably proliferating on its surface and cell viability exceeding 80%. Meanwhile, the E-PGP membrane significantly accelerates L929 cell migration, showing 19% higher scratch healing rate than the PGP group after 24 hours. In promoting collagen secretion, the E-PGP membrane also performs excellently, enabling fibroblasts to synthesize more type I collagen, with related mRNA expression levels 19.1% higher than the control group. For in vitro angiogenesis, the E-PGP membrane shows equally remarkable effects, enabling human umbilical vein endothelial cells (HUVECs) to spread over larger areas, promoting tubular network formation and increasing CD31 expression, effectively promoting angiogenesis at wound sites.

Figure 3. Illustrations presenting the self-powering mechanism, electrical properties and electric field distribution of E-PGP membrane.

Finally, animal experiments further verified the excellent performance of P-E-PGP dressing. In rat full-thickness skin incision model experiments, wounds treated with P-E-PGP dressing healed significantly faster than other groups, achieving nearly complete healing after 14 days with a healing rate as high as 98.5%, far exceeding the control group, PGP group and E-PGP group. Histological evaluation showed that P-E-PGP dressing could effectively reduce inflammatory response, promote epidermal thickening and collagen fiber deposition, and form a high-density vascular network in early wound healing stages, accelerating tissue repair.

Figure 4. In vivo evaluation of wound healing showing healing progression, histological staining observations, and quantitative indicator analysis.

Looking ahead, the research team plans to combine this 5S dressing with smart bioadhesives and smart wearable device platforms to further enhance its convenience and functionality in practical applications. It is believed that in the near future, this new type of wound dressing will be widely used in clinical practice, bringing benefits to more patients with chronic wounds and opening a new chapter in wound care.