Electrophysiological Detection Research Articles

Electrophysiological detection of exam stress inhealth schools' students.

Anxiety is a common issue among university students, many of them experience anxiety, depression, and stress during their school life. This study aimed to compare the acute physiological stress responses of students divided into two groups according to their perceived anxiety levels (positive test anxiety, PTA+, and negative test anxiety, PTA-). Heart rate variability (HRV) and electrodermal activity (EDA) were used to assess stress.Thirty-one healthy volunteers participated in the study. Participants completed anxiety assessments, including the Westside Test Anxiety Scale (WTAS), the State-Trait Anxiety Inventory (STAI), and the Test State Anxiety Inventory (TSAI). Based on their scores, participants were categorized into PTA+ and PTA- groups. All participants underwent 24-h continuous recordings of pulse and electrodermal activity (EDA) on two separate occasions: one day prior to a written exam and during a designated exam-free day serving as a baseline control.We compared the HRV and EDA data obtained on a regular day and on an exam day between the two groups. Results showed that the PTA+ group had significantly higher heart rate, stress index, low frequency, and short-term detrended fluctuation analysis (DFAα1) on the exam day. The tonic EDA component was also higher in the PTA+ group. Stress-related HRV and EDA parameters were negatively correlated with exam scores.In conclusion, the study found that physiological stress indicators obtained from HRV and EDA are associated with perceived exam anxiety in students.

Polymer hydrogel electronics with adhesive, self-healing, and anti-ultraviolet capabilities for machine learning-promoted electrophysiological detection

While adjustable mechanical properties, diverse biochemical features, and good ionic conductivity enabled by molecular engineering, polymer hydrogels as ionic skins (i-skins) are still limited by multiple challenges in the practical human health monitoring and health diagnosis, such as undesirable ductility and contact adhesion, poor functionality, and insufficient sensing ability. In view of this, the strategy of multiple dynamic interactions was proposed, and a mussel characteristic double-network polymer composite hydrogel (PG-BT2) with tannic acid and borax as dynamic media was reasonably designed. Due to the dynamic reversible interactions from the crosslinked network combined with special functional groups, the obtained PG-BT2 hydrogel attains remarkable stretchability with >1200 % elongation and good toughness of 268.6 kJ/m−3, and also possesses favorable versatility (e.g., self-healing time <2 s, adhesion strength of 4.62 kPa to pigskin, and UV transmittance of 15.3 % at 365 nm). Additionally, the i-skin derived from the PG-BT2 hydrogel exhibits excellent sensing properties, including a low interface contact resistance of 8.3 kΩ at 1 kHz, fast response/recovery time of 0.657 s/0.348 s, and a wide sensing range of 0–1100 % strain. By combining the hydrogel-based i-skin patch with the wireless circuit connected to a Bluetooth module, the constructed sensor system is capable of accurately monitoring micro-expressions and multi-joint movements. The portable system is also demonstrated to capture high-fidelity signals of electrocardiograms available for training artificial intelligence, achieving differentiation and recognition of blood pressure status, which will greatly benefit health management and intelligent medicine.

AQP4- and Kir4.1-Mediated Müller Cell Oedema Is Involved in Retinal Injury Induced By Hypobaric Hypoxia.

Hypobaric hypoxia is the main cause of high-altitude retinopathy (HAR). Retinal oedema is the key pathological change in HAR. However, its pathological mechanism is not clear. In this study, a 5000-m hypobaric hypoxic environment was simulated. Haematoxylin and eosin (H&E) staining and electrophysiological (ERG) detection were used to observe the morphological and functional changes in the retina of mice under hypobaric hypoxia for 2-72h. Toluidine blue staining and transmission electron microscopy were used to observe the morphology of Müller cells in the hypobaric hypoxia groups. The functional changes and oedema mechanism of Müller cells were detected by immunofluorescence and western blotting. The expression levels of glutamine synthetase (GS), glial fibrillary acidic protein (GFAP), aquaporin 4 (AQP4), and inwardly rectifying potassium channel subtype 4.1 (Kir4.1) in Müller cells were quantitatively analysed. This study revealed that retinal oedema gradually increased with prolonged exposure to a 5000-m hypobaric hypoxic environment. In addition, the ERG showed that the time delay and amplitude of the a-wave and b-wave decreased. The expression of GS decreased, and the expression of GFAP increased in Müller cells after exposure to hypobaric hypoxia for 4h. At the same time, retinal AQP4 expression increased, and Kir4.1 expression decreased. The oedema and functional changes in Müller cells are consistent with the time point of retinal oedema. In conclusion, Müller cell oedema is involved in retinal oedema induced by hypobaric hypoxia. An increase in AQP4 and a decrease in Kir4.1 are the main causes of Müller cell oedema caused by hypobaric hypoxia.

Screening of New Dendrobium officinale Strains Adapted to Karst Forest Environmental Stress Based on Electrophysiological Detection Method

At present, the main methods of breeding Dendrobium officinale (D. officinale) include introduction and domestication, selective breeding, hybrid breeding, and mutation breeding. In the process, traditional methods of field investigation of agronomic traits are often used to select resistant varieties. Although these breeding methods are effective, they have a certain degree of subjectivity and empiricism, and the breeding cycle is long. Electrophysiological instruments were used in this experiment to test the material transport and metabolic capacity of D. officinale in a karst forest epiphytic environment and to quickly evaluate the suitability of different strains of D. officinale in a drought environment. These instruments detected the data on electrophysiological information of leaves of different strains of D. officinale under long-term drought conditions, providing immediate access to the inherent electrophysiological information of the leaves of these strains. Based on the electrophysiological parameters of D. officinale leaves as defined by the inherent electrophysiological information of plants, the water metabolism, nutrient transport, and metabolic capacity in different leaves were evaluated. The key electrophysiological indexes were verified by combining the results of chlorophyll fluorescence and chlorophyll content. The results indicate the following: (1) Parameters defined based on electrophysiological information effectively characterized the differences in intracellular water utilization, the nutrient transport status, and the metabolic capacity of different D. officinale strains. (2) The intrinsic physiological resistance, intrinsic physiological reactance, active nutrient transport capacity, and passive nutrient transport capacity were closely related to the growth status and chlorophyll function of D. officinale leaves. These electrophysiological parameters could serve as critical indicators for evaluating the drought resistance of D. officinale. (3) Under severe drought stress, strain LH1 exhibited less leaf damage, adequate water/nutrient supply, vigorous life activities, and excellent drought resistance. We found that strain LH1 demonstrates better adaptation to the arid environment of karst forest lands. The electrophysiological detection method employed in this study offers a new technique for screening wild-cultivated D. officinale resistance strains. The results indicate that the real-time online leaf electrophysiological information measured by the method in this study can characterize the energy and material metabolism of crops, greatly improving the efficiency of crop-variety selection and reducing costs. These conclusions can be used to obtain real-time information on the transmission of water and nutrients within plant cells and can provide theoretical support for studying the adaptation mechanisms of crops to adverse environments.

Local vaginal bioelectrical impedance can predict preterm delivery in mice.

Preterm birth is a serious pregnancy complication that affects neonatal mortality, morbidity, and long-term neurological prognosis. Predicting spontaneous preterm delivery (PTD) is important for its management. While excluding the risk of PTD is important, identifying women at high risk of PTD is imperative for medical intervention. Currently used PTD prediction parameters in clinical practice have shown high negative predictive values, but low positive predictive values. We focused on sulfated and sialylated glycocalyx changes in the uterus and vagina prior to the onset of parturition and explored the potential of electrophysiological detection of these changes as a PTD prediction parameter with a high positive predictive value. In vivo local vaginal bioelectrical impedance (VZ) was measured using two different mouse PTD models. PTD was induced in ICR mice through the subcutaneous injection of mifepristone or local intrauterine injection of lipopolysaccharide (LPS). The PTD rates were 100% and 60% post-administration of mifepristone (16-20 h, n = 4) and LPS (12-24 h, n = 20), respectively. The local VZ values (15 and 10 h after mifepristone or LPS treatment, respectively) were significantly lower in the PTD group than in the non-PTD group. Receiver operator characteristic (ROC) curve analysis of VZ at 125 kHz as a predictor of PTD showed an area under the ROC curve of 1.00 and 0.77 and positive predictive values of 1.00 and 0.86, for the mifepristone and LPS models, respectively, suggesting that local VZ value can predict PTD. Histological examination of the LPS-treated model 6 h post-treatment revealed increased expression of sulfomucins and/or sulfated proteoglycans and sialomucins in the cervical epithelium, cervical stroma and vaginal stroma. In conclusion, local VZ values can determine sulfated and sialylated glycocalyx alterations within the uterus and vagina and might be a useful PTD prediction parameter.

Simulation and fabrication of in vitro microfluidic microelectrode array chip for patterned culture and electrophysiological detection of neurons

To enable the detection and modulation of modularized neural networks in vitro, this study proposes a microfluidic microelectrode array chip for the cultivation, compartmentalization, and control of neural cells. The chip was designed based on the specific structure of neurons and the requirements for detection and modulation. Finite-element analysis of the chip’s flow field was conducted using the COMSOL Multiphysics software, and the simulation results show that the liquid within the chip can flow smoothly, ensuring stable flow fields that facilitate the uniform growth of neurons within the microfluidic channels. By employing MEMS technology in combination with nanomaterial modification techniques, the microfluidic microelectrode array chip was fabricated successfully. Primary hippocampal neurons were cultured on the chip, forming a well-defined neural network. Spontaneous electrical activity of the detected neurons was recorded, exhibiting a 23.7% increase in amplitude compared to neuronal discharges detected on an open-field microelectrode array. This study provides a platform for the precise detection and modulation of patterned neuronal growth in vitro, potentially serving as a novel tool in neuroscience research.

Sphingomyelinase as modulator of neuromuscular transmission via presynaptic mechanism

Secretory sphingomyelinases are released in response to various types of stress stimuli, including inflammation [1]. Excessive activity and release of these enzymes can be pathological and accelerate age-related neurological changes, neuroinflammation, neurodegenerative disorders, and muscle dysfunction [1–3]. In contrast, sphingomyelinases were detected in areas close to exocytosis sites and dendritic spines, and their inhibition reduced synaptic transmission at both the presynaptic and postsynaptic levels in hippocampal synapses. Deficiency of acid sphingomyelinase results in neurodegenerative Niemann–Pick disease type A. Knockouts of neutral sphingomyelinases in model mice cause motor defects and disorders that resemble the Alzheimer’s disease phenotype [1, 2]. These findings suggest the existence of a mechanism regulating synaptic transmission, which is dependent on sphingomyelinases. In this study, we examined the impact of neutral sphingomyelinase on neurotransmission in mouse diaphragm muscles using microelectrode recordings of postsynaptic responses, exo-endocytic FM dyes, and fluorescent probes sensitive to membrane properties. The researchers discovered that adding sphingomyelinase at a low concentration (0.01 u/ml) for 15 minutes causes disruption of the lipid packaging of selectively synaptic membranes. This disruption leads to ceramide accumulation, a decrease in staining with Alexa Fluor 488 cholera toxin subunit B conjugate (a marker of GM1 ganglioside cluster), and a shift to the green part of the F2N12S fluorescence spectrum (an indicator of the expansion of the lipid-disordered phase). Increased fluorescence of 22-NBD-cholesterol, indicating an increase in membrane fluidity, and enhanced incorporation of exogenous ceramide into the outer monolayer were observed in the synaptic membranes. Increasing sphingomyelinase concentration to 0.1 u/ml intensifies changes in synaptic membranes and leads to corresponding alterations in membrane properties in muscle fiber plasmalemma. Subsequent experiments used a synapse-specific effect on membrane properties by applying sphingomyelinase at a low concentration for 15 minutes. The application of sphingomyelinase did not alter the amplitude and temporal parameters of miniature postsynaptic responses or the resting membrane potential. Additionally, sphingomyelinase (0.01 u/ml) did not change spontaneous secretion and evoked neurotransmitter release in response to single stimuli. However, the activity of sphingomyelinase led to a notable increase in the release of neurotransmitters and the rate of exocytotic unloading of FM dye from synaptic vesicles during nerve stimulation at 10, 20, and 70 Hz frequencies. The effect of sphingomyelinase on neurotransmission potentiation was irreversible and more significant at 10 Hz activity. Experiments involving intermittent nerve stimulation with short bursts of 60 stimuli each at 10 or 20 Hz frequencies, along with brief 0.5-second rest intervals, indicated that sphingomyelinase elevated the short-term facilitation of neurotransmitter release at the onset of each subsequent episode at 10 Hz (but not at 20 Hz) stimulation. Experiments with a combination of electrophysiological detection of evoked postsynaptic responses, monitoring of exocytotic release of the FM1-43 dye, and the use of FM1-43 fluorescence quencher that penetrates through the fusion pores have demonstrated that a significant portion of synaptic vesicles release the neurotransmitter through the transient fusion pore (kiss-and-run mechanism) during high-frequency (70 Hz) activity [4, 5]. Treatment with sphingomyelinase inhibited the neurotransmitter release pathway. As a consequence, the majority of neurosecretion events went through exocytosis, completely incorporating the vesicular membrane into the presynaptic membrane. Sphingomyelin in the membranes of presynaptic and synaptic vesicles is believed to have varying functions in regulating neurotransmitter release. To investigate this theory, we stimulated the exo-endocytosis processes of synaptic vesicles using sphingomyelinase, which provided access to the synaptic vesicle membranes. Under these circumstances, the enhancing impact of sphingomyelinase on neurotransmitter release and FM1-43 exocytosis rate were notably inhibited. Based on the obtained data, we hypothesize that sphingomyelinase disrupts the integrity of lipid rafts and selectively forms ceramide accumulations in synaptic membranes within the muscles at low concentrations. This ultimately leads to an increase in the mobilization of synaptic vesicles towards exocytosis sites during 10–70 Hz activity. Presumably, the synaptic vesicles from a distinct pool, which predominantly mediates the neurotransmission at a frequency of 10 Hz, are the most actively involved in exocytosis under these circumstances. Sphingomyelinase modifies membrane properties and can inhibit the release of neurotransmitters through the fusion pore during high-frequency activity, redirecting exocytosis towards the complete fusion pathway. Hydrolysis of sphingomyelin in both plasma and synaptic vesicle membranes reduces the stimulatory effects of sphingomyelinase, indicating a contrasting role of sphingomyelin in presynaptic and vesicular membranes for controlling neurotransmitter release [5].

Optimizing the Cell-Nanostructure Interface: Nanoconcave/Nanoconvex Device for Intracellular Recording of Cardiomyocytes.

Nanostructures are powerful components for the development of high-performance nanodevices. Revealing and understanding the cell-nanostructure interface are essential for improving and guiding nanodevice design for investigations of cell physiology. For intracellular electrophysiological detection, the cell-nanostructure interface significantly affects the quality of recorded intracellular action potentials and the application of nanodevices in cardiology research and pharmacological screening. Most of the current investigations of biointerfaces focus on nanovertical structures, and few involve nanoconcave structures. Here, we design both nanoconvex and nanoconcave devices to perform intracellular electrophysiological recordings. The amplitude, signal-to-noise ratio, duration, and repeatability of the recorded intracellular electrophysiological signals provide a multifaceted characterization of the cell-nanostructure interface. We demonstrate that devices based on both convex and concave nanostructures can create tight coupling, which facilitates high-quality and stable intracellular recordings and paves the way for precise electrophysiological study.

Establishment of a High Throughput Screening System for GABAA1 Modulators in Living Cells.

The incidence of sleep disorders is more than 27% in the worldwide, and the development of novel sleep drugs that target GABAA receptors is of great interest. Traditional drug screening methods restrict the discovery of lead compounds, the high-throughput screening system is a powerful means for the lead compounds discovery of sleep drug. The GABAA1-CHO cell line stably expressing α1β2γ2L was constituted by cotransfection of α1, β2 and γ2L subunits into CHO-T-Rex cells. The high-throughput screening method of membrane potential targeting GABAAR was established and optimized. The optimized method was used to screen the compound library, and the compounds with high activity were obtained. The active compounds were confirmed in vitro by electrophysiological detection technique, and the sleep effects of compounds in vivo were detected by pentobarbital sodium sleep model in mice. A stable cell line expressing human GABAA1 receptor in CHO-T-Rex cells was generated and used to establish a functional high-throughput screening assay based on the measurement of membrane potential changes in living cells by fluorometric imaging plate reader (FLIPR). The assay was further used to detect the dose-effect relationships of tool compounds, the EC50 values of agonist GABA (137.42 ± 26.31 nM), positive allosteric modulator diazepam (3.22 ± 0.73 μM), and antagonist gabazine (0.16 ± 0.04 μM), blocking agents bicuculine (0.47 ± 0.06 μM) and PTX (6.39 ± 1.17 μM). In the meanwhile, the compounds were screened from a compound library (10000) by the membrane potential dye assay. Selected 4 active compounds were further identified for their EC50 values in vitro by electrophysiological method, the EC50 values of 4 compounds were further determined as 1.37 ± 0.43 μM, 0.69 ± 0.17 μM, 0.77 ± 0.16 μM, and 1.62 ± 0.29 μM. Furthermore, the pentobarbital sleep rate and the sleep time of mice pretreated with 4 active compounds by oral administration were significantly increased compared with mice pretreated with a negative control in vivo experiment. We successfully generated a stable CHO cell line expressing human GABAA1 by induced expression strategy which decreased cytotoxicity. Then, developed an efficient membrane potential detection method for high-throughput screening, the assay based on the stable cell line could distinguish different types of GABAA1 modulators, which would be an effective in vitro system to screen the GABAAR-targeted compounds. Compared with the patch clamp electrophysiological detection method, the membrane potential detection method has higher detection flux for compounds and higher detection sensitivity for active compounds.

Electrophysiological detection of visible wavelengths of artificial lights inducing take-off in adults of Rhodnius prolixus (Hemiptera: Triatominae)

Rhodnius prolixus is the most important vector of Trypanosoma cruzi in the northern part of South America. The compound eyes in adults of R. prolixus are involved in the nocturnal flight dispersion from sylvatic environments into human dwellings. During this behavior, the artificial lights play an important role in attracting R. prolixus; however, it is still not clear whether the compound eyes of this species use different visible wavelengths as a cue during active dispersion. We applied electrophysiological (electroretinography or ERG) and behavioral (take-off) experiments in a controlled laboratory setting to determine the spectral sensitivity of the compound eyes and the attraction of R. prolixus adults to discrete visible wavelengths. For the ERG experiments, flashes of 300 ms at wavelengths ranging between 350 and 700 nm at a constant intensity of 3.4 µW/cm2 were tested after adaptation to darkness and to blue and yellow lights. For the behavioral experiments, the adults were exposed to nine visible wavelengths at three different intensities, and their direction of take-off in an experimental arena was established with circular statistics. The ERG results showed peaks of spectral sensitivity at 470-490 nm and 520-550 nm in adults, while behavioral experiments showed attractions to blue, green and red lights, depending on the intensity of the light stimuli. The electrophysiological and behavioral results confirm that R. prolixus adults can detect certain wavelengths in the visible spectrum of light and be attracted to them during take-off.

INNV-22. A CASE REPORT OF MULTIPLE LESIONS DISAPPEARING AFTER TMZ+TTFIELDS+ DARAFENIB AND TRAMETINIB IN A PATIENT WITH GBM

Abstract A 44-year-old female patient developed the disease with left visual field defect in both eyes. Brain MRI on September 13, 2021, showed irregular masses in the right basal ganglia, thalamus, and hippocampus of temporal lobe, with the lesion extending to the right midbrain and right optic tract. On September 28, 2021, intraoperative total resection of lesions in right gyrus, hippocampus, thalamus and cingulate herniawas performed under nuclear magnetic navigation and electrophysiological detection. The pathological integration diagnosis result was glioblastoma, IDH wild type with TERT C228T mutation, chromosome 7 amplification and BRAF V600E mutation, WHO grade 4, MGMT non-methylation, postoperative visual acuity same as before. Based on the protocols and data of the clinical trials that have been conducted, and the safety of simultaneous use of TTFields during radiotherapy is controllable and patients can benefit, we started the follow-up treatment: standard TMZ (75mg/m2/d), combined with TTFields and retaining the transducer arrays placed on the shaved scalp. The dose of 60/54Gy, 30 times was selected. The application time of TTFields was relatively long throughout the radiotherapy period, and patient compliance was good, with treatment duration of about 20 hours per day. One month after conventional radiotherapy, reexamination indicated that local T1 enhanced hypersignal and PWI showed hyperperfusion. The methionine PET suggested that tumor activity might still exist. We found that the BRAF V600E mutation may provide therapeutic benefit, so this patient was treated with TMZ (standard 5/28 regimen) +TTFields+ Darafenib and Trametinib. Nearly two months after the follow-up treatment, a re-examination found a remarkable phenomenon, the multiple lesions disappeared. At present, the patient continues to be treated with TTFields for a relatively long time, and the skin side effects are only grade ONE. The combination of TTFields with targeted agents and chemotherapy brought clinical benefit to the patient with manageable adverse reactions.

Study of behavioral, electrophysiological response, and the active compounds of the essential oils from six kinds of flowers against Solenopsis invicta Buren (Hymenoptera: Formicidae)

Red imported fire ant (RIFA), Solenopsis invicta Buren, which is an invasive alien ant, causes serious ecological and public safety problems. Concerns about the impact of traditional synthetic pesticides on nontarget organisms, plant essential oils (EOs) as alternative products with lower environmental impact can be used to control insects. The "push-pull" strategy is considered to be a method of controlling the number and distribution of pests through attraction and repulsion. To find active compounds with effect on the behavior of RIFA, 6 types of EO of plant flowers with a strong aroma, including Osmanthus fragrans (Thunb.) Lour., Sophora japonica Linn, Eugenia caryophμllata Thunb., Ligustrum compactum (Wall. exG. Don) Hook.f., Jasminum sambac (L.) Ait., Allium polyrhizum Turcz. Ex Regel were studied by Y-tube experiment, electrophysiological detection (EAG), and gas chromatography-electroantennographic detection (GC-EAD). The results showed that different concentrations of six EOs significantly affected the behavioral selectivity of different castes of RIFA, the data of high concentration-repellent and low concentration-attractive have been recorded. The repellent rate of 1000 μg/ml L. compactum of EO was 68.75 % and the attraction rate of 2 μg/ml of EO was 66.25 % on small worker ants. For large worker ants, both 1000 μg/ml (repellent rate: 72.50 %) and 40 μg/ml (attractive rate: 68.75 %) of L. compactum EO reached an extremely significant difference. As for E. caryophμllata EOs, the repellent rate of male ants was 67.5 % at 1000 μg/ml and 68.75 % of the attraction rate was calculated at 2 μg/ml. The most interesting finding was that all concentrations of L. compactum EOs showed a remarkable attractive effect on virgin ants and the attraction rate of 1000 μg/ml EO reached an extremely significant difference (attraction rate: 72.5 %). The highest absolute EAG values of different castes of RIFA in the EO were followed as: small worker ants (1.8788 mV, J. sambac ), large worker ants (1.5550 mV, O. fragrans ), male ants (1.6088 mV, A. polyrhizum ), and virgin ants (1.2350 mV, E. caryophμllata ). The GC-MS results of the EOs were followed as: the compounds with high content in O. fragrans EO were butyl phthalate (37.95 %) and p -methoxyphenethyl alcohol (16.76 %); the main chemical components in S. japonica EO were benzeneethanol (20.62 %) and phenol (11.16 %); the total contents of eugenol (82.5 %) and aceteugenol (15.81 %) reached 98.31 % in E. caryophμllata EO; the most compound of EO was benzyl alcohol (19.33 %), followed by linalool (18.70 %) in J. sambac EO; the main chemical components of L. compactum EO were benzyl alcohol (17.45 %) and phenethyl alcohol (27.63 %); five compounds, including pentacosane (11.78 %), heptacosane (10.37 %), oleylamide (11.9 %), non-acosane (20.15 %), and octacosane (8.24 %) were the main chemical components in A. polyrhizum EO. The GC-EAD results showed that three compounds (estragole, α -humulene, and caffeine) were identified to have the potential to develop as behavioral orienting chemicals against worker ants of RIFA. Furthermore, several compounds were expected to be developed as attractants for reproductive ants, including eugenol, cis -linalool oxide, furfural, and its analogs. Our data will provide basic materials for the "push-pull" strategy and have the potential to lay the foundation for the eventual development of efficient and safe repellents. • Six kinds of plants flowers essential oils (EOs) with strong special aroma were extracted by steam distillation method. • Different castes of red imported fire ant (RIFA) revealed repellent or attractive activities to the EOs. • The results of electrophysiological (EAG) recordings showed that the EOs triggered the EAG response to different castes of RIFA. • The results of gas chromatography-electroantennographic detection (GC-EAD) showed that 6 compounds have the potential to be developed as behavioral orient chemicals against RIFA.

Scalable Nanotrap Matrix Enhanced Electroporation for Intracellular Recording of Action Potential.

Electrophysiological recording, as a long-sought objective, plays a crucial role in fundamental biomedical research and practical clinical applications. The challenge in developing electrophysiological detection platforms is to combine simplicity, stability, and sensitivity in the same device. In this study, we develop a nanotrapped microelectrode based on a porous PET membrane, which is compatible with large-scale microtechnologies. The nanotraps can promote the protrusion of the local cell membrane in the hollow center and offer a unique nanoedge structure for tight sealing and effective electroporation. We demonstrate that scalable nanotraps can enhance cell-electrode coupling and perform high-quality intracellular recording. Further, the nanoedge-enhanced electroporation and minimally invasive nanotrapped recordings afford much longer intracellular access of over 100 min and permit consecutive electroporation events in a short period of time. This study suggests that the geometry-regulating strategy of the cell-electrode nanointerface could significantly improve the intracellular recording performance of a nanopatterned electrode.

From Materials to Devices: Graphene toward Practical Applications.

Graphene, as an emerging 2D material, has been playing an important role in flexible electronics since its discovery in 2004. The representative fabrication methods of graphene include mechanical exfoliation, liquid-phase exfoliation, chemical vapor deposition, redox reaction, etc. Based on its excellent mechanical, electrical, thermo-acoustical, optical, and other properties, graphene has made a great progress in the development of mechanical sensors, microphone, sound source, electrophysiological detection, solar cells, synaptic transistors, light-emitting devices, and so on. In different application fields, large-scale, low-cost, high-quality, and excellent performance are important factors that limit the industrialization development of graphene. Therefore, laser scribing technology, roll-to-roll technology is used to reduce the cost. High-quality graphene can be obtained through chemical vapor deposition processes. The performance can be improved through the design of structure of the devices, and the homogeneity and stability of devices can be achieved by mechanized machining means. In total, graphene devices show promising prospect for the practical fields of sports monitoring, health detection, voice recognition, energy, etc. There is a hot issue for industry to create and maintain the market competitiveness of graphene products through increasing its versatility and killer application fields.

Ultrasound-guided injection of botulinum toxin type A blocks cardiac sympathetic ganglion to improve cardiac remodeling in a large animal model of chronic myocardial infarction

Strategies to improve various cardiovascular diseases by blocking cardiac sympathetic ganglion have been increasingly available currently. Botulinum toxin type A (BTA), a typical neurotoxin, has been shown to block neural transmission in a safe and long-lasting manner. The aim of the present preclinical study was to assess the efficacy of BTA microinjection to alleviate cardiac remodeling after chronic myocardial infarction (MI) by blocking cardiac sympathetic ganglion in a canine model. Beagles were randomly divided into a control group (saline microinjection with sham surgery), an MI group (saline microinjection with MI), and an MI + BTA group (BTA microinjection with MI). Ultrasound-guided percutaneous BTA or saline injection into the left stellate ganglion (LSG) was performed followed by MI induction via left anterior descending artery occlusion (LADO) or sham surgery. After 30 days, electrocardiography, Doppler echocardiography, LSG function, neural activity, and ventricular electrophysiological detection were performed in all experimental dogs. At the end, LSG and ventricular tissues were collected for further detection. BTA treatment significantly inhibited LSG function and neural activity and improved heart rate variability. Additionally, BTA application alleviated ventricular remodeling, ameliorated cardiac function, and prevented ventricular arrhythmias after 30-day chronic LADO-induced MI. Ultrasound-guided percutaneous microinjection of BTA can block cardiac sympathetic ganglion to improve cardiac remodeling in a large animal model of chronic LADO-induced MI. Ultrasound-guided BTA microinjection has potential for clinical application as a novel cardiac sympathetic ganglion blockade strategy for MI.

Effect of acellular nerve scaffold containing human umbilical cord-derived mesenchymal stem cells on nerve repair and regeneration in rats with sciatic nerve defect.

BackgroundThe aim of the present study was to investigate the effect of acellular nerve scaffold (ANS) containing human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) on nerve repair and regeneration in rats with sciatic nerve defect.MethodsSciatic nerve trunks were removed from 6 female Sprague-Dawley (SD) rats, and ANS was prepared by lyophilization + enzymatic method and divided into A, B, C, D and E groups according to different treatment times. hUC-MSCs were isolated from the collected umbilical cords and cultured, and then ANS-hUC-MSCs complexes were made. The other 24 adult female SD rats were randomly divided into the control, autograft, ANS, and ANS-hUC-MSCs groups, and a rat model of sciatic nerve defect was established. Hematoxylin-eosin (HE) staining, Luxol fast blue (LFB) staining, Masson staining, and scanning electron microscopy were used to observe the morphology and tissue structure of ANS. The performance of ANS was evaluated by mechanical detection, and hydroxyproline (HYP) content was evaluated using a biochemical kit. Flow cytometry was adopted to detect the levels of hUC-MSCs surface antigens CD29, CD44, and CD34, as well as electrophysiological detection and muscle wet weight recovery rate for measuring rat muscle performance.ResultsANS was prepared according to group A method and had good mechanical properties, with less residues of cells and myelin, and higher HYP content, indicating that this scaffold had the best performance. ANS-hUC-MSCs significantly reduced myelin injury in the sciatic nerve, and increased axonal regeneration, effectively improving sciatic nerve injury in rats. In addition, ANS-hUC-MSCs significantly increased compound muscle action potential (CMAP), nerve conduction velocity (NCV), and muscle wet weight, and reduced muscle atrophy.ConclusionsANS containing hUC-MSCs can promote nerve repair and regeneration in rats with sciatic nerve defects.

Clinical Value Analysis of High-Frequency Ultrasound Combined with Carpal Dorsiflexion Electrophysiological Detection in the Diagnosis of Early Carpal Tunnel Syndrome.

Objective To investigate the clinical value of ultrasound combined with electrophysiological examination in the diagnosis of early carpal tunnel syndrome, we aimed to provide a new EMG (electromyography) method for detecting early carpal tunnel syndrome by exploring the wrist back stretch position and electrophysiological examination. Methods For the 82-lateral wrist (case group) of 62 patients with clinical symptoms or confirmed carpal tunnel syndrome and 40 normal healthy patients, neuroelectrophysiological measurements were performed using a Keypoint6.0 EMG evoked potentiometer, measuring each group twice: conventional position (before compression) and dorsal wrist extension position. The measures for each measurement included DSL, DML, and CAMP. Measure sensory conduction first and then measure motor conduction. The measurements were analyzed in a comprehensive comparative analysis. Combined ultrasound examination, the positive rate of combined ultrasound examination and electrophysiological examination was compared, respectively. Results In the carpal tunnel syndrome (CTS) group, the anterior and posterior median nerve DSL was (4.27 ± 0.73) ms and (4.82 ± 0.65) ms, and SNAP was (13.32 ± 13.68) UV and (12.19 ± 11.04) UV; the median nerve (wrist-bunions) DML was (5.29 ± 1.26) ms and (5.54 ± 1.29) ms, and CMAP was (6.44 ± 2.40) mV and (6.21 ± 2.46) mV. Mid-median DSL and DM in the CTS group L were significantly longer than before compression; median nerve SNAP and CMAP were significantly reduced compared with before compression. Conclusion Electrophysiological testing at the dorsal carpal extension position has high diagnostic value in the diagnosis of mild carpal tunnel syndrome. It helps to improve the diagnostic rate of early carpal tunnel syndrome, while providing a more accurate and effective EMG detection of early carpal tunnel syndrome, and combination examination of neuroelectrophysiology and ultrasound can improve the diagnosis rate of compression peripheral nerve diseases and clarify the site, nature, and scope of compression lesions, which is worthy of clinical application.

High-Throughput PEDOT:PSS/PtNPs-Modified Microelectrode Array for Simultaneous Recording and Stimulation of Hippocampal Neuronal Networks in Gradual Learning Process.

When it comes to mechanisms of brain functions such as learning and memory mediated by neural networks, existing multichannel electrophysiological detection and regulation technology at the cellular level does not suffice. To address this challenge, a 128-channel microelectrode array (MEA) was fabricated for electrical stimulation (ES) training and electrophysiological recording of the hippocampal neurons in vitro. The PEDOT:PSS/PtNPs-coated microelectrodes dramatically promote the recording and electrical stimulation performance. The MEA exhibited low impedance (10.94 ± 0.49 kohm), small phase delay (-12.54 ± 0.51°), high charge storage capacity (14.84 ± 2.72 mC/cm2), and high maximum safe injection charge density (4.37 ± 0.22 mC/cm2), meeting the specific requirements for training neural networks in vitro. A series of ESs at various frequencies was applied to the neuronal cultures in vitro, seeking the optimum training mode that enables the neuron to display the most obvious plasticity, and 1 Hz ES was determined. The network learning process, including three consecutive trainings, affected the original random spontaneous activity. Along with that, the firing pattern gradually changed to burst and the correlation and synchrony of the neuronal activity in the network have progressively improved, increasing by 314% and 240%, respectively. The neurons remembered these changes for at least 4 h. Collectively, ES activates the learning and memory functions of neurons, which is manifested in transformations in the discharge pattern and the improvement of network correlation and synchrony. This study offers a high-performance MEA revealing the underlying learning and memory functions of the brain and therefore serves as a useful tool for the development of brain functions in the future.

Neurotrophic factors combined with stem cells in the treatment of sciatic nerve injury in rats: a meta-analysis.

Treatment of peripheral nerve regeneration with stem cells (SCs) alone has some limitations. For this reason, we evaluate the efficacy of neurotrophic factors combined with stem cell transplantation in the treatment of sciatic nerve injury (SNI) in rats. PubMed, Cochrane Library, Embase, WanFang, VIP and China National Knowledge Infrastructure databases were retrieved from inception to October 2021, and control experiments on neurotrophic factors combined with stem cells in the treatment of SNI in rats were searched. Nine articles and 551 rats were included in the meta-analysis. The results of meta-analysis confirmed that neurotrophic factor combined with stem cells for the treatment of SNI yielded more effective repair than normal rats with regard to sciatic nerve index, electrophysiological detection index, electron microscope observation index, and recovery rate of muscle wet weight. The conclusion is that neurotrophic factor combined with stem cells is more conducive to peripheral nerve regeneration and functional recovery than stem cells alone. However, due to the limitation of the quality of the included literature, the above conclusions need to be verified by randomized controlled experiments with higher quality and larger samples.

Data from single nuclei RNA‐sequencing reveals a prodromal gene network response in excitatory neurons of a humanized rat Alzheimer’s disease model

AbstractBackgroundDespite significant investment into treatments for AD, little progress has been made in bringing new therapeutics to market. Recent failure of monoclonal antibodies targeting Ab plaques to slow disease progression in phase 3 clinical trials, suggests now more than ever it is imperative to identify early disease signatures before symptom onset whose modification may alter disease trajectory. Our collaborating lab recently identified early dysfunction in the transgenic tri‐synaptic hippocampal circuit using in vivo recordings during awake immobility in the TgF344‐AD rat model (doi: 10.1101/2021.05.10.443512). This dysfunction emerges between 6‐9 months, prior to when TgF344‐AD rat shows overt pathology (including Ab plaques, frank neuronal loss, and endogenous tau pathology) at 16 and 26 mo, but not at 6 mo (Towne, 2013).MethodsThe molecular basis of this trisynpatic circuit dysfunction was explored using 10x Genomics’ v3 gene expression assay to perform snRNA‐seq on freshly dissected hippocampi from 6 mo male and female littermate pairs of Tg and Wt rats (n=16). ∼2000 cells/subject were collected, and cDNA libraries were sequenced (NovaSeq 600) to a depth of ∼120k reads/nuclei. Cell Ranger Pipeline demultiplexed and aligned reads to rat pre‐mRNA reference and generated gene count matrices. A final dataset of 33,079 high quality nuclei were clustered (Louvain graph‐based), and cell‐type specific marke used to determine identity. Identity was collapsed into broad neuronal and glial cell types for differential gene expression (DEG) across genotype (Hurdle Model).ResultsDEGs revealed profound alterations between genotype in cell types important in the trisynaptic circuit, including dentate granule cells (DGCs), and excitatory neurons (ExcNs). (FDR cutoff=0.05, 1111 (DGCs) and 1070 (ExcN’s) DEGs between genotypes). Pathway enrichment revealed dysregulation relevant to memory function: including decreased synaptogenesis, neurite branching, proliferation, and microtubule and cytoskeleton dynamics. DEG’s were enriched for neurological signs including epilepsy, seizures, hyperactivity, and dementia.ConclusionPrior to development of overt pathology or memory deficits, TgF344‐AD rats display transcriptomic alterations in their excitatory neurons, suggestive of impaired ability to form new connections and susceptibility to aberrant, hyperactivity. Electrophysiological detection, followed by intervention targeting these early alterations in gene expression may prevent progression of disease to a symptomatic stage.