Investigation of Lorentz field effects on wound healing: theoretical, computational, and experimental analysis

Objective.This study introduces a novel non-invasive wound healing method that generates Lorentz fields (LFs) in the wound area using ultrasonic transducers under a static magnetic field, enabling localized stimulation without direct electrode contact.Approach.Theoretical derivations of the governing equations, supported by numerical simulations, demonstrate the feasibility and potential effectiveness of this technique. The model includes the two-dimensional geometry of the wound, skin layers, gel, a single-element ultrasonic probe, or a 16-element linear phased array (LPA) transducer. The pressure and velocity current density distributions in the wound area were analyzed under three different excitation configurations: (i) excitation using a single-element ultrasonic probe, (ii) beam steering of the LPA transducer at 5^∘intervals between-30∘and+30∘at 13 different angles, and (iii) focusing of the LPA transducer at 0^∘. In each configuration, distinct pressure distributions and velocity current density patterns were obtained in the wound region. In addition,in vivoanimal experiments were conducted using the single-element ultrasonic probe to evaluate the biological effects of LF-based stimulation on wound healing. The study included four experimental groups: a static magnetic field (SMF) group, an ultrasound (US) group, a combined LF group, and a control group without any stimulation.Main results.In the single-element probe configuration, the simulated velocity current density reached approximately 4.51μAcm-2, corresponding to a pressure of 0.17 MPa. These values remained within the established safety limits while being sufficient to promote wound healing. For the LPA transducer, electronic beam steering enabled a uniform distribution of acoustic pressure and induced current density over a wider wound area. The pressure ranged between ±(0.118-0.203)  MPa, and the corresponding velocity current density varied between ±(2.33-2.69) μAcm-2. In the focusing configuration (0^∘), the maximum pressure in the wound region reached 0.285 MPa, while the peak absolute velocity current density was 6.72 μAcm-2, both remaining within safe limits. Animal experiments were conducted for 14 d, with each group receiving a 5 min daily treatment. The Lorentz-field group exhibited the fastest wound closure, followed by the US and magnetic-field groups, whereas the control group showed the least improvement.Significance.The proposed method offers an innovative and safe alternative for accelerating wound healing by combining US and SMFs to generate Lorentz-induced current densities in the wound, providing localized and non-invasive therapeutic stimulation.