OBJECTIVE: To explore the preparation of nano-silver acupuncture needles and evaluate the appearance, structure and properties. METHODS: Stainless steel acupuncture needles were pretreated by polishing with sandpaper and cleaning with ultrapure water and absolute ethanol. As the working electrodes, the needles were placed in an electrolyte solution contained silver nitrate (AgNO₃), potassium nitrate (KNO₃), and polyvinylpyrrolidone (PVP); and the silver nanoparticles were deposited at a constant voltage of -0.2 V for 1 200 s. The heat-treatment was conducted at 600 ℃ for 15 min in an argon atmosphere to strengthen the adhesion between the nanoparticles and the substrate. The surface appearance and structure of nano-silver acupuncture needles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrical conductivity, thermal conductivity and biocompatibility of the needles were evaluated. The cytotoxicity and biocompatibility of the sample were assessed using the CCK-8 assay. According to the national standard, Acupuncture Needles (GB 2024-2016), the other physicochemical performances of nano-silver acupuncture needles were tested. RESULTS: ①By controlling the AgNO₃ concentration and the molar ratio of AgNO₃ to PVP, it was found that at an AgNO₃ concentration of 2 mmol/L and a molar ratio of 5∶1, silver nanoparticles with the diameter of 50-100 nm, regular appearance, and uniform distribution were obtained. At a lower concentration, the size of silver nanoparticles was smaller and unevenly distributed particles, whereas a higher concentration tended to produce a dendritic structure. ②By sandpaper polishing, acid etching pretreatment, and heat-treatment at 600 ℃ under argon for 15 min, the adhesion of silver nanoparticles on the surface of the needle body was strengthened, and the simulated pig skin puncture test showed the intact coating without shedding. ③SEM found that the silver nanoparticles were uniformly deposited, forming a nanofilm approximately 1.5 μm thick; XRD analysis showed the diffraction peaks corresponding to cubic crystal silver (111), (200), (220) and (311); and XPS detected characteristic peaks of Ag 3d3/2 and Ag 3d5/2, confirming the successful deposition and good crystallinity of the silver nanoparticles. ④Resistivity measurements indicated that the nano-silver acupuncture needles exhibited a resistivity of approximately 0.15 Ω·cm, about three times lower than that of unmodified stainless steel needles. The infrared thermography demonstrated that their thermal conductivity was superior to that of traditional acupuncture needles. In vitro CCK-8 cytotoxicity assay showed that the nano-silver acupuncture needles had no adverse effects on human skin fibroblasts and possessed good biocompatibility. ⑤ The key parameters such as needle tip performance, hardness, and the adhesion between the needle body and handle were in compliance with the requirements in Acupuncture Needles (GB 2024-2016), ensuring a quality guarantee provided for clinical applications. CONCLUSION The preparation of nano-silver acupuncture needles effectively overcomes the insufficient toughness of traditional silver needles and improves the electrical and thermal conductivity of stainless acupuncture needles.
Silver/chemistry* ; Needles ; Acupuncture Therapy/instrumentation* ; Metal Nanoparticles/chemistry* ; Humans ; Electric Conductivity ; Animals

The evaluation of blood compatibility of biomaterials is crucial for ensuring the clinical safety of implantable medical devices. To address the limitations of traditional testing methods in real-time monitoring and electrical property analysis, this study developed a portable electrical impedance tomography (EIT) system. The system uses a 16-electrode design, operates within a frequency range of 1 to 500 kHz, achieves a signal to noise ratio (SNR) of 69.54 dB at 50 kHz, and has a data collection speed of 20 frames per second. Experimental results show that the EIT system developed in this study is highly consistent with a microplate reader ( R ²=0.97) in detecting the hemolytic behavior of industrial-grade titanium (TA3) and titanium alloy-titanium 6 aluminum 4 vanadium (TC4) in anticoagulated bovine blood. Additionally, with the support of a multimodal image fusion Gauss-Newton one-step iterative algorithm, the system can accurately locate and monitor in real-time the dynamic changes in blood permeation and coagulation caused by TC4 in vivo. In conclusion, the EIT system developed in this study provides a new and effective method for evaluating the blood compatibility of biomaterials.
Electric Impedance ; Animals ; Tomography/instrumentation* ; Biocompatible Materials ; Materials Testing/instrumentation* ; Cattle ; Titanium ; Alloys ; Prostheses and Implants

Real-time acquisition of pulmonary ventilation and perfusion information through thoracic electrical impedance tomography (EIT) holds significant clinical value. This study proposes a novel method based on the rime (RIME) algorithm-optimized variational mode decomposition (VMD) to separate lung ventilation and perfusion signals directly from raw voltage data prior to EIT image reconstruction, enabling independent imaging of both parameters. To validate this approach, EIT data were collected from 16 healthy volunteers under normal breathing and inspiratory breath-holding conditions. The RIME algorithm was employed to optimize VMD parameters by minimizing envelope entropy as the fitness function. The optimized VMD was then applied to separate raw data across all measurement channels in EIT, with spectral analysis identifying relevant components to reconstruct ventilation and perfusion signals. Results demonstrated that the structural similarity index (SSIM) between perfusion images derived from normal breathing and breath-holding states averaged approximately 84% across all 16 subjects, significantly outperforming traditional frequency-domain filtering methods in perfusion imaging accuracy. This method offers a promising technical advancement for real-time monitoring of pulmonary ventilation and perfusion, holding significant value for advancing the clinical application of EIT in the diagnosis and treatment of respiratory diseases.
Humans ; Electric Impedance ; Algorithms ; Tomography/methods* ; Pulmonary Ventilation/physiology* ; Lung/diagnostic imaging* ; Image Processing, Computer-Assisted/methods* ; Adult

Electrical impedance tomography (EIT) is a new non-invasive functional imaging technology, which has the advantages of non-invasion, non-radiation, low cost, fast response, portability and visualization. In recent years, more and more studies have shown that EIT has great potential in the detection of lung diseases and has been applied to early diagnosis and treatment of some diseases. This paper introduced the basic principle of EIT, discussed the research and clinical application of EIT in the detection of acute respiratory distress syndrome, chronic obstructive pulmonary disease, pneumothorax and pulmonary embolism, and focused on the summary and introduction of indicators and functional images of EIT related to the detection of lung diseases. This review will help medical workers understand and use EIT, and promote the further development of EIT in lung diseases as well as other fields.
Humans ; Electric Impedance ; Tomography/methods* ; Lung Diseases/diagnosis* ; Pulmonary Disease, Chronic Obstructive/diagnosis* ; Pulmonary Embolism/diagnosis* ; Respiratory Distress Syndrome/diagnosis*

To address the challenges of capturing micro-strains in detecting esophageal motility disorders and the limitations of existing high-resolution manometry and functional intraluminal imaging probes in directly measuring esophageal tissue electrical impedance, this study proposes a novel flexible balloon sensor structure that integrates a piezoelectric film assembly with a distributed impedance electrode array. Using the electrical analysis module in the finite element analysis (FEA) software, simulations of the forward problem for esophageal impedance detection were conducted to optimize the excitation source parameters, and a physical prototype was fabricated. Under a relative excitation mode with a voltage sensitivity of 2.059%, the voltage output characteristics of the impedance electrode array were analyzed during linear changes in the balloon filling volume. Based on the performance variation of the piezoelectric film assembly, 80% was selected as the optimal filling volume. Force-electric coupling tests were conducted on the balloon sensor using a pressure testing platform, revealing that both the piezoelectric film assembly inside the balloon and the impedance electrodes outside the balloon exhibited significant load differentiation characteristics as the force application point shifted. In summary, this balloon sensor facilitates the localization of force application while simultaneously analyzing esophageal tissue properties, offering a novel diagnostic approach and objective tool for esophageal disease detection.
Esophagus/physiology* ; Electric Impedance ; Humans ; Finite Element Analysis ; Manometry/methods* ; Electrodes ; Esophageal Motility Disorders/physiopathology* ; Equipment Design

Flexible conductive fibers have been widely applied in wearable flexible sensing. However, exposed wearable flexible sensors based on liquid metal (LM) are prone to abrasion and significant conductivity degradation. This study presented a high-sensitivity LM conductive fiber with integration of strain sensing, electrical heating, and thermochromic capabilities, which was fabricated by coating eutectic gallium-indium (EGaIn) onto spandex fibers modified with waterborne polyurethane (WPU), followed by thermal curing to form a protective polyurethane sheath. This fiber, designated as Spandex/WPU/EGaIn/Polyurethane (SWEP), exhibits a four-layer coaxial structure: spandex core, WPU modification layer, LM conductive layer, and polyurethane protective sheath. The SWEP fiber had a diameter of (458.3 ± 10.4) μm, linear density of (2.37 ± 0.15) g/m, and uniform EGaIn coating. The fiber had excellent conductivity with an average value of (3 716.9 ± 594.2) S/m. The strain sensing performance was particularly noteworthy. A 5 cm × 5 cm woven fabric was fabricated using polyester warp yarns and SWEP weft yarns. The fabric exhibited satisfactory moisture permeability [(536.06 ± 33.15) g/(m ²·h)] and maintained stable thermochromic performance after repeated heating cycles. This advanced conductive fiber development is expected to significantly promote LM applications in wearable electronics and smart textile systems.
Wearable Electronic Devices ; Polyurethanes/chemistry* ; Electric Conductivity ; Gallium/chemistry* ; Metals/chemistry*

OBJECTIVES: To assess the changes in body composition and nutritional risks faced by children with different stages of acute leukemia (AL). METHODS: Bioelectrical impedance analysis combined with anthropometric measurements was used to detect body composition. This prospective study was conducted from August 2023 to July 2024 at Shandong Provincial Hospital, examining the body composition and physical balance of children with various stages of AL and healthy children. RESULTS: The non-fat components of children with AL and healthy children both showed a linear increase with age. In the younger age group, there were no significant differences in body composition between children with AL and healthy children. However, in the older age group, the body composition of children undergoing chemotherapy for AL was significantly lower than that of healthy children (P<0.05), and muscle mass recovered first after the completion of AL chemotherapy. The proportion of children with increased trunk fat in AL children who completed chemotherapy was significantly lower than that in healthy children (P<0.05), while the incidence rate of severe left-right imbalance in body composition was significantly higher (P<0.05). Muscle distribution in children with AL primarily showed insufficient limb and overall muscle mass, whereas healthy children mainly exhibited insufficient upper limb muscle mass. CONCLUSIONS The body composition of children with AL varies at different treatment stages, indicating that nutritional status is affected by both the disease itself and the treatment. Early screening can provide a basis for reasonable nutritional intervention.
Humans ; Child ; Male ; Female ; Child, Preschool ; Body Composition ; Prospective Studies ; Adolescent ; Leukemia/metabolism* ; Infant ; Nutritional Status ; Acute Disease ; Electric Impedance

Electrical impedance tomography (EIT) is a technique that uses an array of electrodes to deliver safe stimulating currents and measures the boundary voltages between adjacent electrode pairs in the array in sequence. Subsequently, it reconstructs the impedance distribution in all or part of the tissue using reconstruction algorithms to achieve structural and functional imaging. Lung EIT technology features continuity, being radiation-free and non-invasive, and it can be used for real-time dynamic monitoring of the lungs in critically ill patients. This paper introduces the basic principles of lung EIT, analyzes the research progress and existing problems of the technology from the perspectives of hardware systems, imaging algorithms, and clinical applications (such as lung ventilation, lung perfusion, and lung function assessment), and discusses the development direction to provide ideas for expanding the clinical application of lung EIT.
Electric Impedance ; Humans ; Tomography/methods* ; Lung Diseases/therapy* ; Algorithms

The minimally invasive thermal ablation technology differs from traditional surgical operations, which requires auxiliary equipment to evaluate ablation results. However, the ultrasound and CT currently used in clinical practice have shortcomings such as artifacts and radiation. Therefore, this paper proposes a design for a minimally invasive thermal ablation evaluation system based on the principle of electrical impedance tomography technology to monitor the ablation range. At the same time, the innovative introduction of a programmable gain feedforward signal as the parameter signal of the multiplier demodulator in the electrical impedance tomography system design can effectively solve the problem of weak signals being submerged in noise and improve imaging accuracy. The system controls the amplitude of the excitation current signal and the acquisition / processing of boundary voltages via an STM32, uploads the collected data to an upper computer, and reconstructs the conductivity distribution using the Newton-Raphson algorithm to map the size of the ablation area. Experimental results show that the system can effectively reflect the size of the microwave ablation area. Under the same minimally invasive ablation parameters, the average imaging errors are 0.6 mm for the long diameter, 0.8 mm for the short diameter, and 1.75% for the axial ratio (long diameter / short diameter), demonstrating high consistency. This verifies the technical potential of electrical impedance tomography in minimally invasive thermal ablation.
Electric Impedance ; Tomography/instrumentation* ; Equipment Design

Electrical impedance tomography (EIT) represents an emerging medical functional imaging technology, which operates by applying safe-to-human excitation currents through surface-mounted electrodes, measuring boundary voltages between electrodes, and selecting appropriate image reconstruction algorithms to visualize resistivity in tomographic cross-sections. Compared to traditional medical imaging techniques, EIT offers non-invasive and radiation-free operation, high sensitivity to tissue resistivity changes, and superior temporal resolution, meeting the real-time requirements of clinical dynamic condition monitoring. This paper comprehensively reviews the research status of brain EIT technology, systematically summarizes its advantages and technical limitations in perioperative applications, and prospectively forecasts future development directions of perioperative brain EIT based on current research foundations and clinical application demands, with the aim of providing methodological references for further optimization and clinical promotion of this technology.
Electric Impedance ; Tomography/methods* ; Humans ; Brain/diagnostic imaging*