Abstract
Chronic and large skin wounds present significant clinical challenges due to delayed healing and high infection risk. Pulsed electromagnetic field (PEMF) therapy is a non-invasive approach that can promote tissue repair. This study describes a reproducible rat wound model protocol using a flexible printed copper coil patch connected to a custom PCB controller to deliver localized PEMF stimulation to full-thickness dorsal wounds. The contralateral wound served as an untreated control. Healing progression was assessed through regular photography and wound area measurements. The protocol provides a practical, adaptable system for evaluating and optimizing PEMF-based therapies in vivo across various conditions, with a focus on localized application and parameter adjustment for regenerative medicine. Parameter selection was based on an orthogonal CCK-8 screen of fibroblast proliferation that tested 0.25-1.3 mT, 10-40 Hz, and 30-90 min/day; main-effect analysis identified 1.3 mT, 30 Hz, and 60 min/day as the optimal levels, which were adopted for in vivo testing.
Discussion
Critical steps include creating symmetric full-thickness wounds, ensuring the coil patch lies flat over a sterile barrier without gaps, and maintaining consistent daily exposure; deviations can reduce field delivery and increase variability in healing outcomes.
This work has several limitations that should be considered when interpreting the findings and assessing translational potential. First, the protocol was demonstrated in healthy male SD rats (6-8 weeks, 200-250 g) with acute excisional wounds, and therefore does not fully capture clinically compromised healing environments such as diabetes, ischemia, infection, aging, or immunosuppression. In addition, only a single PEMF parameter set (1.3 mT, 30 Hz, 60 min/day) was evaluated in vivo, and this regimen was selected based on an in vitro fibroblast proliferation screen; optimal dosing may vary with species, wound type and depth, dressing or barrier thickness, and the biological process being targeted (e.g., inflammation, angiogenesis, or remodeling). Although simulations and the device design support localized delivery, the effective field at the wound surface may still vary with coil-to-tissue spacing, barrier thickness, and patch alignment, potentially introducing day-to-day fluctuations in the delivered dose.
Moreover, while the contralateral within-subject design improves efficiency and controls for inter-animal variability, outcomes may be influenced by systemic responses to wounding and repeated handling; a separate cohort incorporating sham (unpowered coil) and untreated controls helps mitigate this concern, but systemic and behavioral confounds cannot be completely eliminated in vivo. Finally, healing assessments focused primarily on macroscopic closure measured by planimetry at discrete time points and on endpoint histology/angiogenesis markers (e.g., day 14, n = 6 per group), leaving longer-term outcomes — such as scar quality, tensile strength, barrier restoration, recurrence, and durability beyond the 14-day window — unresolved.
Additionally, although our study focused on acute wounds in healthy rats and a single parameter set, the approach can be extended to models of chronic or compromised healing. Previous research suggests that magnetic field therapies may also benefit diabetic wound healing in animal models and clinical trials10,11,17,18. Future studies could apply this wearable PEMF system to such models to evaluate broader translational potential and refine dosing.
Link to full article: here
Zhang, C., Ma, J., Ma, Z., Lyu, G. Flexible Electromagnetic Coil Patch-enhanced Healing of Full-Thickness Skin Wounds in Rats. J. Vis. Exp. (228), e69605, doi:10.3791/69605 (2026).
