Characterization of a non-invasive dielectrophoresis ratchet microelectrode for electric-field-assisted HEK cell alignment and accumulation within defined gaps: <i>in vitro</i> study

Purpose Patients with diabetes are at risk of developing chronic wounds, which can take months or years to heal naturally. This study aims to present the in vitro characterization of a dielectrophoresis (DEP) ratchet microelectrode for electric-field-assisted cell positioning (i.e. alignment and accumulation within defined gaps) of human epidermal keratinocytes (HEK) to enhance epithelialization in chronic wound environments. Design/methodology/approach MyDEP and COMSOL Multiphysics 5.6 were used to validate the experimental results. The DEP microelectrode was designed using AutoCAD and fabricated using surface micromachining to produce 40 and 60 µm ratchet microelectrodes. DEP experiments were performed by applying sinusoidal AC potentials of 8, 10 and 12 VPP to the fabricated microelectrodes over a frequency range of 100 kHz to 25 MHz. The motion analysis software DIPP-MotionV was used to track cell positioning and accumulation and estimate cell speed. Findings The DEP experimental results, including cell positioning velocity and DEP response, were validated and correlated with the finite element method (FEM) and MyDEP data. The study successfully achieved in vitroHEK cell positioning at a rate of 263.33 µm/s at 5 MHz, 8 VPP using a 40 µm ratchet microelectrode. Cell viability assessment further confirmed that HEK cells remain viable at 8 VPP, supporting its suitability as a biologically safe operating condition. Furthermore, the device performance was compared between 40 and 60 µm ratchet microelectrodes for effective cell positioning within defined gaps, achieving an efficiency of approximately 83.67% to 95.05%. Originality/value The DEP-based approach for in vitroHEK cell positioning within defined gaps using a 40 µm ratchet microelectrode demonstrates high efficiency, indicating its potential for enhancing wound epithelialization and enabling rapid chronic wound closure.