Quantum modeling of Stokes-Induced Stark Fields in quercetin-ZnO nanohybrids for bias-free bioelectric repair of chronic diabetic foot ulcers.

CONTEXT: Chronic diabetic foot ulcers (DFUs) are associated with the collapse of endogenous bioelectric field gradients and redox-compromised wound microenvironments, conditions under which externally applied electroceutical stimulation and reactive oxygen species (ROS)-dominated photodynamic therapies become ineffective or deleterious. This limitation motivates the search for intrinsic, bias-free mechanisms capable of generating localized bioelectric-scale fields using benign external energy inputs. At photoactive organic-semiconductor interfaces, excited-state intramolecular proton transfer (ESIPT) offers a pathway by which molecular photophysics may be converted into interfacial electrostatic modulation, yet this transduction mechanism has not been formulated within a rigorous quantum-electrostatic framework.

METHOD: Here, we develop a first-principles quantum modeling framework establishing the Stokes-Induced Stark Effect (SISE) at quercetin-ZnO interfaces as a bias-free mechanism for interfacial electric field generation. Visible-light excitation of chemisorbed quercetin induces ultrafast ESIPT-driven Stokes relaxation, accompanied by excited-state dipole reconfiguration (Δµ ≈ 5-15 D, τ ≈ 100 fs). This time-dependent dipole couples electrostatically to ZnO surface states, generating localized interfacial Stark fields of order 105-106 V·m⁻1. Using a composite molecular-semiconductor Hamiltonian incorporating dielectric screening and surface-state quantization, we show that although instantaneous fields are strongly attenuated in physiological media (Debye length λ D ≈ 0.8 nm), spatiotemporal integration via dipole-density gradients and continuous low-intensity illumination yields effective quasi-static comparable in magnitude to endogenous bioelectric signals at the interface ( E eff ≈ 50 - 500 V · m - 1 ). The model explicitly avoids assumptions of static field penetration and instead delineates a defined operational window (coverage factor η ≈ 0.3-0.7; illumination < 10 mW·cm⁻2) in which electrostatic guidance dominates over ROS-driven photochemistry. The framework provides quantitative design constraints and experimentally testable predictions, establishing SISE as a physically plausible molecular photophysics-driven route for bias-free bioelectric modulation, with chronic wound repair serving as a representative application context.