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

<i>Objective.</i>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.<i>Approach.</i>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,<i>in vivo</i>animal 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.<i>Main results.</i>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.<i>Significance.</i>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.