Accurate and reliable measurement of the electrical impedance spectrum is an essential requirement in order to draw relevant conclusions in many fields and a variety of applications; in particular, for biological processes. Even in the state-of-the-art methods developed for this purpose, the accuracy and efficacy of impedance measurements are reduced in biological systems, due to the regular occurrence of parameters causing measurement errors such as residual impedance, parasitic capacitance, generator anomalies, and so on. Recent observations have reported the necessity of decreasing such inaccuracies whenever measurements are performed in the ultra-low frequency range, as the above-mentioned errors are almost entirely absent in such cases. The current research work proposes a method which can reject the anomalies listed above when measuring in the ultra-low frequency range, facilitating data collection at the same time. To demonstrate our hypothesis, originating from the consideration of the determinant role of the measuring frequency, a physical model is proposed to examine the effectiveness of our method by measuring across the commonly used vs. ultra-low frequency ranges. Validation measurements reflect that the range of frequencies and the accuracy is much greater than in state-of-the-art methods. Using the proposed new impedance examination technique, biological system characterization can be carried out more accurately.

Metabolic dysfunction–associated steatotic liver disease (MASLD) is a highly prevalent multisystem disorder and is strongly associated with increased cardiovascular risk. Cardiovascular diseases represent the leading cause of mortality in this population. As the hepatic manifestation of systemic metabolic dysfunction, MASLD is initiated by excess lipid accumulation driven by increased dietary fatty acid intake and accelerated de novo lipogenesis. This triglyceride overload induces lipotoxicity, triggering hepatocellular injury, immune activation, and mitochondrial dysfunction. Excessive mitochondrial reactive oxygen species (ROS) generation acts as a critical second hit, promoting inflammatory cytokine production and disease progression. Beyond lipid dysregulation, impaired hepatic insulin signaling leads to hyperglycemia and compensatory hyperinsulinemia, further stimulating lipogenesis and reinforcing a self-perpetuating metabolic cycle. Persistent ROS production overwhelms antioxidant defenses and depletes hepatic glutathione (GSH), resulting in systemic redox imbalance. These disturbances extend beyond the liver, contributing to atherogenic dyslipidemia and chronic inflammation. In parallel, gut dysbiosis and increased intestinal permeability amplify immune activation. Reduced circulating GSH further weakens systemic antioxidant capacity; oxidative stress may represent a central mechanistic link between MASLD and CVD. In concert with metabolic and inflammatory mediators, ROS disrupt pathways governing vascular and myocardial homeostasis, leading to coronary atherosclerosis, microvascular dysfunction, left ventricular remodeling, hypertrophy, and impaired relaxation. Clinically, this translates into an increased burden of coronary artery disease and heart failure, particularly heart failure with preserved ejection fraction. Given this integrated pathophysiology, early identification of subclinical cardiovascular involvement is essential. We highlight emerging biomarkers, advocate for multidisciplinary screening strategies, and discuss integrated pharmacological approaches targeting shared metabolic pathways. Recognizing MASLD as a cardiovascular risk amplifier is critical for improving risk stratification and enabling the development of effective, co-targeted therapeutic strategies.

Based on a prior university patent, the authors developed a novel type of bioimpedance-based test method to noninvasively detect nonalcoholic fatty liver disease (NAFLD). The development of a new potential NAFLD diagnostic procedure may help to understand the underlying mechanisms between NAFLD and severe liver diseases with a painless and easy-to-use paraclinical examination method, including the additional function to detect even the earlier stages of liver disease. The aim of this study is to present new results and the experiences gathered in relation to NAFLD progress during animal model and human clinical trials.

The crucial issue in electrical impedance (EI) measurements lies in the galvanic interaction between the electrodes and the investigated material. This paper brings together the basic and applied research experience and combines their results with excellent properties. Consequently, innovative precise methodologies have emerged, enabling the direct modeling of EI measurements, free from the inaccuracies often associated with numerical approaches. As an outcome of the efficiency and robustness of the applied method, the conductivity of the material and the electrodes are represented by a common piecewise function, which is used to solve the differential equation modeling of the EI measurement. Moreover, this allows the possibility for modeling the conductivity of electrodes with continuous functions, providing an important generalization of the Complete Electrode Model (CEM), which has been widely used so far. The effectiveness of the novel approach was showcased through two distinct case studies. In the first case study, potential functions within both the material and the electrodes were computed using the CEM. In the second case study, calculations were performed utilizing the newly introduced continuous electrode model. The simulation results suggest that the new method is a powerful tool for biological research, from in vitro experiments to animal studies and human applications.

Bioimpedance spectrum (BIS) measurements are highly appreciated in in vivo studies. This non-destructive method, supported by simple and efficient instrumentation, is widely used in clinical applications. The multi-frequency approach allows for the efficient extraction of the most information from the measured data. However, low-frequency implementations are still unexploited in the development of the technique. A self-developed BIS measurement technology is considered the pioneering approach for low (<5 kHz) and ultra-low (<100 Hz) frequency range studies. In this paper, the robustness of ultra-low frequency measurements in the prototypes is examined using specially constructed physical models and a dedicated neural network-based software. The physical models were designed to model the dispersion mainly in the ultra-low frequency range. The first set of models was used in the training of the software environment, while the second set allowed a complete verification of the technology. Further, the Hilbert transformation was employed to adjust the imaginary components of complex signals and for phase determination. The findings showed that the prototypes are capable of efficient and robust data acquisition, regardless of the applied frequency range, minimizing the impact of measurement errors. Consequently, in in vivo applications, these prototypes minimize the variance of the measurement results, allowing the resulting BIS data to provide a maximum representation of biological phenomena.

This work investigates the suitability of a custom-developed Bioimpedance Spectroscopy (BIS) sensor for the in vitro detection of microand nanoplastics, as well as the measurement conditions required to obtain reliable signal changes. The behavior of polystyrene-based particles across different concentrations, sizes, and surface coatings was explored. Experiments were conducted using in-house developed sensing plates and suspensions containing plastic fractions of various size ranges. The methodology included fabrication of the plates, validation with saline solutions, preparation of surface coatings, and repeated BIS measurements. Based on the results, particle detectability was characterized, and the effects of surface coatings on adhesion and washability were assessed. These findings provide a foundation for the development of standardized in vitro platforms and for future toxicological applications.