Background: Electrical stimulation is a novel tool to promote the differentiation and proliferation of precursor cells. In this work we have studied the effects of direct current (DC) electrical stimulation on neuroblastoma (N2a) and osteoblast (MC3T3) cell lines as a model for nervous and bone tissue regeneration, respectively. We have developed the electronics and encapsulation of a proposed stimulation system and designed a setup and protocol to stimulate cell cultures. Methods: Cell cultures were subjected to several assays to assess the effects of electrical stimulation on them. N2a cells were analyzed using microscope images and an inmunofluorescence assay, differentiated cells were counted and neurites were measured. MC3T3 cells were subjected to an AlamarBlue assay for viability, ALP activity was measured, and a real time PCR was carried out. Results: Our results show that electrically stimulated cells had more tendency to differentiate in both cell lines when compared to non-stimulated cultures, paired with a promotion of neurite growth and polarization in N2a cells and an increase in proliferation in MC3T3 cell line. Conclusions: These results prove the effectiveness of electrical stimulation as a tool for tissue engineering and regenerative medicine, both for neural and bone injuries. Bone progenitor cells submitted to electrical stimulation have a higher tendency to differentiate and proliferate, filling the gaps present in injuries. On the other hand, neuronal progenitor cells differentiate, and their neurites can be polarized to follow the electric field applied.

Electrical pulse stimulation has been used to enhance the differentiation or proliferation of neuronal progenitor cells in tissue engineering and cancer treatment. Therefore, a comprehensive investigation of the effects caused by its parameters is crucial for improvements in those fields. We propose a study of pulse parameters, to allow the control of N2a cell line fate and behavior. We have focused on designing an experimental setup that allows for the knowledge and control over the environment and the stimulation signals applied. To map the effects of the stimulation on N2a cells, their morphology and the cellular and molecular reactions induced by the pulse stimulation have been analyzed. Immunofluorescence, rt-PCR and western blot analysis have been carried out for this purpose, as well as cell counting. Our results show that low-amplitude electrical pulse stimulation promotes proliferation of N2a cells, whilst amplitudes in the range 250 mV/mm–500 mV/mm induce differentiation. Amplitudes higher than 750 mV/mm produce cell damage at low frequencies. For high frequencies, large amplitudes are needed to cause cell death. An inverse relation has been found between cell density and pulse-induced neuronal differentiation. The best condition for neuronal differentiation was found to be 500 mV/mm at 100 Hz. These findings have been confirmed by up-regulation of the Neurod1 gene. Our preliminary study of the molecular effects of electrical pulse stimulation on N2a offers premonitory clues of the PI3K/Akt/GSK-3β pathway implications on the neuronal differentiation process through ES. In general, we have successfully mapped the sensitivity of N2a cells to electrical pulse stimulation parameters.

Heart failure (HF) is a complex syndrome in which the heart is unable to pump enough blood containing oxygen and nutrients to meet the body’s demands. HF is the leading cause of hospitalization for patients over 65 years of age. After a patient is diagnosed with HF, the mortality rate is 50% within the first 5 years. Presently, there is no unanimous diagnostic criteria for HF. Bioimpedance (BI) analysis has been proposed in recent years as a technique to detect one of the main symptoms: changes in body volume due to edema. This research presents a portable device (Volum), capable of performing real-time BI measurements in a low cost and non-invasive way. The goal is to improve patient monitoring at home to ensure rapid intervention in cases of worsening conditions, either with timely hospitalizations or adjustments to a patient’s usual treatment. Volum is a small, wearable, wireless, lightweight, low-power clinical pilot prototype, that takes measurements through four electrodes and sends the data via Bluetooth to an Android device.

Heart failure (HF) is a severe disease and one of the most important causes of death in our society nowadays. A significant percentage of patients hospitalized for decompensation of heart failure are readmitted after some weeks or months due to an expected bad and uncontrolled HF evolution due to the lack of the patient supervision in real time. Herein is presented a straightforward electric model useful for volume leg section calculus based on the bioimpedance test as a way to assist with the acute HF patient’s supervision. The method has been developed for time-evolution edema evaluation in patients’ corresponding legs. The data are picked up with a wearable device specifically developed for acute heart failure patients. As an initial step, a calibration method is proposed to extract the extracellular volume component from bioimpedance measurements done in healthy subjects, and then applied to unhealthy ones. The intra- and extracellular resistance components are calculated from fitted Cole–Cole model parameters derived from BI spectroscopy measurements. Results obtained in a pilot assay, with healthy subjects and heart failure subjects, show sensitivities in leg volume [mL/Ω], with much lower values for healthy than in unhealthy people, being an excellent biomarker to discriminate between both. Finally, circadian cycle evolution for leg volume has been measured from the bioimpedance test as an extension of the work, enabling an alternative parameter for the characterization of one day of human activity for any person.

Congestive heart failure is a chronic disease that affects millions of people worldwide, characterized by the inability of the heart to pump enough blood with oxygen and nutrients, leading to fluid accumulation. Monitoring fluid accumulation is crucial in managing the disease, but current noninvasive methods have limitations in terms of size and connectivity. This study introduces Volum, a wearable device that measures calf bioimpedance to remotely monitor the progression of edema in patients with congestive heart failure. The device was first tested on a known RRC circuit, demonstrating high accuracy with a maximum error of 1%. It was also tested in 2 volunteers (1 patient and 1 control) for one month. The result showed consistent impedance values in the control throughout the month, while the patient showed high variability, in addition to a lower bioimpedance value. The results suggest the potential of the device for noninvasive monitoring of bioimpedance evolution. However, more research is needed to validate the measurements in a larger patient population and to explore the potential of the device for improving patient outcomes.

Cancer therapies based on differentiation processes are strategies that try to induce the maturation of cancer cells into a differentiated and not proliferating state, aiming in this way to arrest the tumor growth. While conventional therapies often lack specificity and can harm normal cells, differentiation strategies have shown to be promising but they still remain limited in clinical application. Electrical stimulation (ES), which should not be confused with electroporation, has been shown to induce specific cellular responses, including differentiation. Here we showed that voltage-controlled biphasic pulses at 500 mV/mm and 100 Hz suppresses proliferation and promotes neuronal differentiation in the neuroblastoma cell line N2a, both in monolayer and 3D neurosphere cultures. The morphological changes induced by ES associated with neuronal differentiation, downregulated proliferation markers (H3S10ph and Ki-67), modulated neuronal differentiation markers (Neurod1 and SOX2) and reduced colony and neurosphere formation, all this without causing DNA damage. Therefore, ES represents a non-genotoxic mechanism to halt tumor cell growth, distinguishing it from standard cytotoxic therapies. These findings suggest that ES offers a means to suppress proliferation and induce differentiation in neuroblastoma cells, providing a potential foundation for less harmful therapeutic strategies targeting this pediatric cancer.