Abstract:Acetylcholine, the first identified neurotransmitter, plays crucial roles in various brain functions. One well-known case is its involvement as an activating neurotransmitter in the regulation of locomotion. However, its inhibitory regulatory role, particularly in locomotion, remains poorly understood. In a study conducted by Polat et al., the authors investigated the inhibitory role of acetylcholine in locomotion in C. elegans. In this organism, the acetylcholine-gated chloride channel receptor consists of four subunits. The authors thoroughly examined the loss-of-function of each subunit in movement regulation. Interestingly, the mutant worms were still capable of performing various movements such as forward, backward crawling, and turning, suggesting that the overall movement was not significantly affected. However, quantitative behavior analysis revealed subtle yet significant differences in the timing and postures of the movement in these mutants. Furthermore, the authors employed optogenetics to stimulate a specific neuron involved in backward crawling and demonstrated that the loss-of-function of the receptors in individual neurons affects the transitioning between locomotion modes.
This work provides evidence for the inhibitory regulatory role of acetylcholine in locomotion. The loss-of-function of acetylcholine-gated chloride channel receptors likely disrupts the balance of neuronal and circuit physiology, thereby affecting the regulation of locomotion. Moreover, this study highlights the powerful role of quantitative behavior analysis in discovering and understanding more sophisticated functions of neural circuits.

Abstract:Quercetin, a natural flavonol compound found in traditional Chinese medicine, fruits, vegetables, and medicinal plants, has been the subject of numerous studies due to its potential therapeutic value[1]. Accumulated studies have demonstrated that quercetin can modulate neuronal excitability via different underlying mechanisms in the central nervous system[2-3]. However, the specific effects and mechanisms of quercetin in the central nervous system are still controversial, especially in the field of basic synaptic transmission.
The calyx of Held synapse displays classic features of conventional synapse, such as the presence of calcium, sodium, and potassium ion channels in the presynaptic nerve terminals, the ability to generate action potentials, and short-term synaptic plasticity[4-5]. Li et al. (Prog Biochem Biophys, 2023, 50(6): 1391-1402. DOI: 10.16476/j. pibb. 2023.0191) investigated the presynaptic effect of quercetin using capacitance measurement techniques at the giant glutamatergic central synapse, the calyx of Held, which provides a unique feasibility to study the presynaptic kinetics of synaptic transmission. The authors showed that quercetin inhibits presynaptic vesicle endocytosis without affecting calcium influx and exocytosis. The slowdown of endocytosis further leads to inhibition of vesicle mobilization and the replenishment of the readily releasable pool (RRP). In addition, the quercetin-induced inhibition of vesicle endocytosis and RRP replenishment enhances the short-term depression (STD) during high-frequency repetitive stimulation.
This study provides new insights into the quercetin-modulated presynaptic mechanisms at the synapse of the calyx of Held and suggests a protective effect that prevents excessive excitatory synaptic transmission in brain circuits. On the other hand, the specific roles of quercetin in different brain regions (e. g., cortex, hippocampus) remain to be explored in combination with the whole neural circuit. Finally, extensive basic research is required to confirm the exact treatment and the mechanism of quercetin in clinical diseases.

Abstract:Coronavirus disease 2019 (COVID-19) is a global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since olfactory dysfunction is the main neurological symptom of COVID-19, it is important to examine the prevalence, underlying mechanisms, and recovery trajectories of COVID-19-related olfactory dysfunction for the promotion of public health. Reported prevalence rates of COVID-19-related olfactory dysfunction vary widely across studies due to differences in the assessment of olfactory function, demographic background, and the predominant SARS-CoV-2 strains around the time of data collection. Specifically, different SARS-CoV-2 strains differ in the stability of spike glycoproteins and the host-cell infection pathways and thus efficacy in infecting the olfactory epithelium. In general, SARS-CoV-2 has been shown to cause inflammatory obstruction of the olfactory cleft, death of supporting cells, and host immune responses in the olfactory epithelium. Whether and how it invades into the central olfactory system remain controversial. Some individuals with “long COVID” suffer from chronic olfactory loss. The pathological mechanisms likely involve persistent inflammation in the olfactory epithelium and disruption of its regeneration triggered by SARS-CoV-2 infection. Based on the olfactory vector hypothesis, SARS-CoV-2 may affect central nervous system function by way of the olfactory system and could potentially induce neurodegeneration in the long term. Available interventions for managing olfactory dysfunction from SARS-CoV-2 infection include olfactory training and pharmacotherapy.

Abstract:Regulatory T cells (Tregs) are T lymphocytes that perform immunomodulatory functions. By providing accurate, efficient, safe and controlled regulation of systemic immunity, Tregs play a key role in the treatment of autoimmune diseases and immune rejection after organ transplantation. However, Tregs have clinical limitations such as off-targeting and functional phenotype instability. Genetic and biomedical engineering are promising strategies to promote Treg active targeting and chemotaxis to the inflammation site, and to maintain Treg Forkhead box protein 3 (Foxp3) expression during immune-regulation. Herein, Treg anti-inflammatory mechanisms, engineering tactics and bulk production methods are systematically summarized. By anti-inflammatory cytokine secretion, Granzyme B release or effector T cell metabolism intervention, Tregs can inhibit effector T cell proliferation and activation, or even kill immune cells. Moreover, expressing genetically modified receptors (CARs, TCRs and CXCRs) or conjugating nanomaterials onto cell surface, can help enhance targeted recognition and maintain anti-inflammatory function of Tregs. Artificial antigen-presenting-cells or costimulatory molecules can stimulate Treg cell proliferation and activation. By prospecting the application of biomedical-engineered Tregs in autoimmune diseases, organ transplantation and other inflammatory diseases, this work aims to inspire and promote the clinical application of Tregs adoptive therapy.

Abstract:Liposomes are hollow spheres composed of lipids bilayer membranes, which can encapsulate and deliver hydrophilic and hydrophobic substances. Liposomes are promising nano-drug delivery systems due to low immunogenicity, good stability, low toxicity and cost. Currently, a variety of liposome drugs for tumor treatment have been listed. Liposomes can accumulate in tumor tissues via enhanced permeability and retention effect (EPR) and are internalized into tumor cells by endocytosis or pinocytosis. Subsequently, liposomes are intracellularly cleaved to release drugs, thereby killing tumor cells. Liposomes that rely on the EPR effect are called passive targeting liposomes, which lack the ability to specifically recognize target tissues. However, active targeting liposomes can achieve targeting delivery via the specific binding between the targeting modifiers on the surface of liposomes and receptors on the surface of tumor cells. These receptors such as peptides, carbohydrates, ligands, antibodies and nucleic acid aptamers on the surface of tumor cells overexpress due to rapid growth of tumor cells and needs of nutrients and related growth factors. Thus, liposomes can be reasonably designed according to these specific receptors. Recent years, some studies have reported biomimetic liposomes by coating the cell membrane on the surface of liposomes, however, the research on biomimetic liposomes is still in its infancy, and there are still many problems to be solved. Additionally, since the length is limited, biomimetic liposomes are not reviewed in this paper. Taken together, liposomes as potential drug carriers, not only protect drugs, but also reduce side effects, importantly, they can precisely target tumor tissues through introducing targeting modifiers. In this work, we review the improvement of targeting function of liposome by five targeting modifiers including peptides, carbohydrates, ligands, antibodies and nucleic acid aptamers, and summarize the existing advantages and challenges of various targeted modifications. Finally, this review is expected to provide scientific reference for the LPs drug delivery system study and theoretical basis for the drug development.

Abstract:Ferroptosis is a kind of cell death triggered by the accumulation of iron-dependent lipid peroxidation products. Like apoptosis, necroptosis, it belongs to the regulated cell death. Numerous studies have shown that ferroptosis is linked to various diseases, such as cancer, neurodegenerative disease and stroke. Activation or inhibition of ferroptosis may play an important role in the treatment of related diseases. Regulating ferroptosis to intervene the occurrence and development of diseases has become a hotspot and focus of current research. Although people have made important discoveries in the molecular regulation of various cell death pathways, the differences in morphological characteristics have important practical significance for pathology departments to identify cell death types and guide the formulation of clinical treatment plans. As a new regulated form of cell death, ferroptosis has many different manifestations from other forms of cell death, among which cell morphological changes are markedly characterized. With the in-depth study of different cell death modes, further analysis and comparison of the morphological characteristics of different cell death forms, and exploration of their similarities and differences are of great significance for identifying cell death forms, judging the pathological process of diseases, and finding appropriate treatment options. This article focuses on the comparison of the morphological features of ferroptosis with other forms of cell death, such as apoptosis, necroptosis, autophagy and pyroptosis. The article shows that ferroptosis has the morphological characteristics of increased mitochondrial membrane densities, reduced or vanished mitochondria crista, rupture of outer mitochondrial membrane. It is obviously different from the morphological features of apoptosis (plasma membrane blebbing, cellular and nuclear volume reduction, mitochondria, Golgi and other organelles in cytoplasm condense, nuclear fragmentation, chromatin condensation and formed apoptotic bodies), autophagy (formation of double membraned autolysosomes), necroptosis (cells become round, swelling of the cytoplasm and organelles, moderate chromatin condensation and rupture of plasma membrane), and pyroptosis (cell edema and membrane rupture, karyopyknosis). We also highlight the involvement of ferroptosis in the major progression of stroke, neurodegenerative diseases and cancer. This paper provides an important basis for the identification and diagnosis of different pathological features.

Abstract:Noise exists widely in the environment, and the rapid development of urbanization also increases the chance for wildlife to be exposed to anthropogenic noise. There is growing evidence that anthropogenic noise affects human health and the survival of wild animals in many ways. A summary of these studies shows that anthropogenic noise can change the physiological state of animals, make them at a relatively high stress level, decrease their immune ability, reduce the activity of antioxidant enzymes, and induce higher reative oxygen species (ROS) level. Animals exposed to anthropogenic noise have significantly shorter telomere lengths and lower telomerase activity. Anthropogenic noise can also decrease the learning and cognitive ability of animals, and even affect the development of brain regions related to vocal learning. For example, male zebra finch exposed to traffic noise at an early stage had smaller relative volumes of area X and high vocal centers. The effects of anthropogenic noise on animal behaviors are also extensive. The presence of anthropogenic noise can interfere with foraging behaviors and increase the risk of predation. Meanwhile, anthropogenic noise may mask sound signals and affect animal communication, such as changing acoustic signals and reducing communication space. The accumulation of these factors may reduce the survival rate of animal offspring, change the species abundance, and pose a threat to the survival of animals. There are differences in the sensitivity of different species to noise, and the changes of physiological state and behaviors induced by noise may also be different. The research on the non-auditory effects of anthropogenic noise is helpful to understand the potential harms of noise and take active mitigation measures to deal with them.

Abstract:Cell-bacterial interactions refer to the process in which bacterium or bacterial metabolites act on the host cells, causing cellular and bacterial changes in morphology and functions. Cell-bacterial interactions researches are of vital significance to life sciences fields, such as drug development, disease diagnosis, and medical therapy. Recently, the detection and analysis of cell-bacterial interactions have developed rapidly. Cellular and bacterial morphology, activity, barrier function, and metabolites are the important clues to detect cell-bacterial interactions, which are essential to reveal deeper inflammatory disease mechanisms. Because of the controlled environment, good biocompatibility, multi-detection, and miniaturization, microfluidic analysis technology is developing into a powerful tool of cell-bacterial interaction research. In this review, we first introduce cell-bacterial analysis methods and technologies based on the microfluidic chip analysis briefly. Then the cell-bacterial interactions models based on the microfluidic chip are discussed, and later focusing on cell-bacterial interactions detection by microfluidic analysis technology, especially on the application of optical and electrochemical methods integrated with microfluidic chips. Microfluidic optical analysis system combines the chip with different microscopes, which is widely used for cellular and bacterial morphology imaging, and providing more details about metabolites with spectrometry during cell-bacterial interactions. Microfluidic electrochemical analysis system usually assemble directly microelectrodes on the chip, and its main advantage is monitoring dynamically cell-bacterial interaction through changes in electrical signals. By integrating microfluidics technologies and various detecting modules, microfluidic analysis technology has become an advantageous platform for cell-bacterial interactions analysis. Finally, the challenges and future development for microfluidic photoelectric detection technology in cell-bacterial interactions are discussed and prospected.

Abstract:Molecular imprinted technology has been applied to identify template molecules by using molecular imprinted polymers to simulate the interaction between enzymes and substrates or antibody and antigens. In recent years, to meet the needs of efficient microbial detection, bacteria, cells and other microbial imprinted technologies has been gradually derived from molecular imprinted technology, which was of the advantages of selective capture, effective separation and enrichment of targets, and easy to integrate sensing detection technology and so on. In this review, the latest advances of bacteria imprinted technology were introduced and summarized, including imprinting materials, imprinting mechanisms, detecting techniques and their typical applications. Firstly, the principle of bacteria imprinting was introduced. The materials of surface imprinting and the preparation methods of direct imprinting, indirect imprinting and electropolymerization were summarized. The applications and progress of bacteria imprinted sensing monitoring based on different analytical methods, such as fluorescence, electrochemistry, quartz crystal microbalance (QCM) and so no, were discussed in details. Especially, the analytical methodology based on microfluidic chip integrated with bacteria molecular imprinting was presented. Finally, the existing challenges of related fields and developing trends were put forward. It was illustrated that the imprinting technologies for bacteria, cells and other microbial could be widely adopted in the fields of biochemical separation and analysis because of its stability of material structure and specificity of target identification.

Abstract:Memory is an essential function for accumulating experience and promoting individual survival. However, post-traumatic stress disorder (PTSD) and substance use disorders (SUD) are characterized by maladaptive memory, which is unfavorable for individual survival. Therefore, one idea to develop treatment for PTSD and SUD, psychiatric disorders characterized by excessive fear memories or addiction memories, is to extinguish or update maladaptive memories. Memory intervention is based on the fact that memory is an ongoing process that allows updating and integrating information. The reactivation of memory may induce memory retrieval and reconsolidation, rendering a time window with increase plasticity of the neural circuits underlying the pieces of the retrieved memory. Interventions within this critical time window may have better therapeutic effect compared to interventions outside the time window. Noninvasive brain stimulation (NIBS), as a non-invasive physical therapy, has been viewed a candidate for maladaptive memory intervention. NIBS can be applied with specific stimulation parameters (anatomical targets, frequency, polarity, behavioral state, etc.) to achieve varied stimulation effects. NIBS can alter cortical excitability and modulate neuroplasticity in the targeted region or other brain regions connected to the targeted region. When NIBS is applied to memory related brain areas, it may disrupt or alter memory-related neural circuit activity thereby changing memory related emotion or behavioral performance. In this review, we summarize recent studies using NIBS (transcranial magnetic stimulation, TMS, and transcranial direct current stimulation, tDCS, mainly) interventions for trauma- or substance-use-related memory during memory reconsolidation, along with theoretical basis from brain imaging or preclinical evidence from rodent studies. There are two basic ideas for NIBS interventions in maladaptive memories, to enhance activity in extinction-related neural circuit by TMS or tDCS, or to suppress activity in brain areas related to maladaptive emotional or motivational processing during memory reconsolidation. Both ideas got supporting results from research in the laboratory, while there has been no convincing evidence from clinical application yet. This review summarizes research evidence about the application of NIBS in fear and addiction memory intervention and hopes to contribute to breed insights for the development of NIBS treatment for memory-related psychiatric disorders targeting reconsolidation process.

Abstract:Diabetic cognitive dysfunction refers to the impairment of cognitive function in diabetic patients, which is a common complication of diabetes. This is especially true for elderly patients with type 2 diabetes mellitus. Studies have shown that adipokines, such as adiponectin (APN) and leptin (LEP) secreted from adipose tissue are implicated not only in the regulation of energy metabolism, but also in the development and progression of diabetic cognitive dysfunction. APN and LEP may serve as biomarkers for diabetes-related cognitive dysfunction. They can cross the blood-brain barrier, enter the brain, and regulate multiple physiological processes such as hippocampal neurogenesis, synaptic plasticity, neuroinflammation, oxidative stress, and neuronal apoptosis by binding to the receptors on neurons or glial cells (e.g., microglia and astrocytes), and activating or inhibiting downstream intracellular signaling pathways, including p38MAPK, AMPK, ERK, JAK2/STAT3, PI3K/AKT, and SIRT1/PGC-1α, etc., and subsequently regulate cognitive function. Importantly, APN and LEP may also act as key mediators in the improvement of diabetic cognitive dysfunction by physical exercise. This study aimed to open up ideas for further enriching the theoretical system of “fat-brain” crosstalk, and developing and refining the diagnosis and treatment strategies of diabetic cognitive dysfunction through analyzing the relationship between APN or LEP and diabetic cognitive dysfunction, sorting out the underlying biological mechanism of APN and LEP regulating cognitive function, and exploring the possible mechanism of exercise-mediated APN and LEP in improving diabetic cognitive dysfunction.

Abstract:As a complex system, axons need to extend a long distance to form synapses with next neurons or target cells in the development of nervous system. During this complex movement, neuronal axons form precisely ordered structures in their spatial distribution. In the past, it was thought that the formation of such ordered structures was mainly guided by the chemical concentration gradient of morphogenesis. However, recent studies have found that mechanical cues play an important role in regulating the neurite initiation, elongation and sprouting, nerve fasciculation, and neuron maturation. Thus, axon extension is essentially a mechano-chemical coupling process. This paper discusses the origin of the cellular forces controlling axon growth and pathfinding, the mechanism of axons perceiving mechanical stimuli from the environment, and the mechanism of mechanical force regulating axon extension and related signal transduction. We also discuss how forces are generated and sensed in vivo, and which molecular mechanisms are responsible for responding to mechanical signals. The research in this field will provide important reference for understanding the neurological diseases and nerve regeneration.

Abstract:Accumulating evidence suggests that perceptual, emotional, and cognitive processes depend on ongoing neural oscillatory activities, which are easy to be entrained by rhythmic sensory stimuli, non-invasive transcranial electrical or magnetic stimulation, and invasive brain stimulation. Compared with other modulatory approaches, rhythmic sensory stimulation is economical and uncomplicated to implement, thus it has been considered a highly promising means of neuromodulation in recent years. To get a better understanding of this neuromodulatory approach, we present a systematic review of rhythmic auditory stimuli induced neural entrainment and its applications. Specifically, we discuss whether and how rhythmic auditory stimulation selectively modulates brain oscillations and its impact on human behaviors accordingly. Multiple lines of evidence have suggested that entrainment of neural oscillations to auditory stimulations could alter specific aspects of perception, emotion, and cognitive functions, depending on the frequency and types of stimulation applied. Moreover, we review the advantages of rhythmic auditory stimulation as a tool in clinical practice, such as motor rehabilitation, and highlight the possibility to use rhythmic auditory stimulation on modulating emotion and cognitive functions. Last, we discuss and summarize the physiological mechanisms and applicational prospects of rhythmic stimulation as a neuromodulatory technique. Based on the current state of knowledge, rhythmic auditory stimulation can be considered a simple and efficient way to enhance human brain functions.

Abstract:Objective Acetylcholine is a highly conserved neurotransmitter that plays a crucial role in the regulation of animal motor behavior. Abnormalities in acetylcholine signaling can lead to various motor dysfunctions. However, the inhibitory regulatory mechanisms of acetylcholine in motor behavior are not fully understood. In this study, we used Caenorhabditis elegans as a model organism to investigate the regulatory effects of acetylcholine-gated chloride channel receptor subunits (ACC-1, ACC-2, ACC-3, ACC-4) on motor behavior.Methods We used a combination of locomotion tracking, molecular genetics, and optogenetics to analyze C. elegans locomotion in acetylcholine-gated chloride channel subunit deficient mutants.Results We found that mutations in these subunits affected the kinematics of forward, backward, and turning movements of nematodes. The body bending amplitude during forward movement was also modified. Optogenetic activation of RIB interneurons led to delayed termination of the reversal in these mutant strains.Conclusion These results suggest that the regulation of acetylcholine-gated chloride channel subunits is required for maintaining and modulating C. elegans motor states. They also suggest that these subunits may be involved in mediating the inhibitory regulation of RIB interneurons on backward movement in C. elegans. This study provides new insights into the regulatory mechanisms of acetylcholine-gated inhibitory receptors in motor behavior.

Abstract:Objective Quercetin, a flavonol compound widely distributed in fruits, vegetables, and medicinal plants, has been suggested to act as a neuroprotective agent. In the present study, we investigated the presynaptic effect of quercetin on synaptic transmission and plasticity.Methods Using whole-cell patch clamp and capacitance measurement technique, we recorded miniature excitatory postsynaptic currents (mEPSC), presynaptic calcium influx, vesicle release and recycling, and the replenishment of readily releasable pool (RRP). Additionally, we stimulated the axon with 5-200 Hz and recorded short-term depression (STD) in the postsynaptic neuron.Results We found that 100 μmol/L quercetin in the extracellular solution did not affect the mEPSC amplitude and frequency, indicating a presynaptic mechanism modulating synaptic transmission. At the presynaptic nerve terminals, 100 μmol/L quercetin did not induce notable changes in calcium influx or vesicle release, but significantly inhibited clathrin-dependent slow endocytosis following exocytosis. The inhibition of endocytosis led to a slowdown of vesicle mobilization during stimulation, a reduction in readily releasable pool replenishment after stimulation, and enhancement of short-term depression during high-frequency repetitive stimulation in the postsynaptic principal neurons.Conclusion These results provide new insights into quercetin-modulated neuronal signaling and suggest a protective effect that prevents excessive excitatory synaptic transmission in brain circuits.

Abstract:Objective Coxsackie virus group B type 5 (CVB5) is one of the causative agents of hand-foot- mouth disease, which can cause clinical symptoms such as fever, rash or herpes, and neurological complications or even fatalities. The innate immune response is the first line of defense against the viral infection, and the nuclear factor-κB (NF-κB) is a master regulator in the control of immune responses. However, little research has been reported on the regulation of the NF-κB mediated signaling pathway after CVB5 infection. This study explores the regulatory mechanism of virus and the host innate immune response, providing targets for the development of drugs against CVB5 infection.Methods In this study, promoter activity, proinflammatory factor and key proteins expression were detected to investigate the regulatory mechanism of CVB5 on NF-κB signaling.Results CVB5 infection inhibited the expression of proinflammatory factors and the phosphorylated p65 protein expression. Non-structural protein (NSP) of CVB5 inhibited the expression of proinflammatory factor and important proteins, such as the phosphorylated p65 and IκBα. CVB5 3CD interacted with the host polycytosine binding protein 1 (PCBP1) was performed via the STRING 11.1 database, and the PCBP1 inhibited viral replication by promoting the phosphorylation of IκBα and p65.Conclusion These results showed that CVB5 NSP negatively regulated NF-κB signaling pathway, and the PCBP1 protein which interacted with 3CD could inhibit CVB5 replication through activate the NF-κB pathway.

Abstract:Objective The venom of carnivorous cone snails provides a valuable source of biologically active peptides, which are composed of a complex mixture of disulfide-rich neurotoxins, commonly known as conotoxin. In this work, a novel O2 superfamily conotoxin Tx7.29 was reported, and through functional research, it is expected to discover a new analgesic drug candidate.Methods The cDNA sequence of Tx7.29 was obtained from the venom duct cDNA library of the molluscivorous Conus textile collected from the South China Sea. The mature peptide Tx7.29 with modified amino acids and disulfide bonds was synthesized and identified by mass spectrometry. Patch clamp and animal experiments were used to determine the biological function of Tx7.29.Results The cDNA of Tx7.29 encodes a 68 amino acid residues conotoxin precursor, which consists of 19 residues in the signal peptide, 28 residues in the pro-region and 22 residues in the mature peptide. Circular dichroism (CD) spectra showed that β-turn and antiparallel sheet structures were dominant contents in Tx7.29. Patch clamp experiments on the rat DRG neurons showed that Tx7.29 could significantly inhibit calcium currents, but it had no obvious effects on the sodium and potassium currents. Tx7.29 increased the hot plate latency from 0.5 to 4 h in a dose dependent manner in the mice hot plate assay and had low toxicity to ND7/23 cells.Conclusion This novel conotoxin Tx7.29 may be a useful tool for analgesic drug development and could expand our visions of the molecular targets of O2-conotoxins.

Abstract:Objective Orbital bone fracture has become very common in recent years, and its related treatments and therapies aim at repairing the defects. Mineralized poly (γ-glutamic acid)/2-hydroxyethyl methacrylate/poly(ethylene glycol) (γ-PGA/HEMA/PEG) polymeric cryogel is a new type of scaffolding material with an interconnective porous structure. The study aimed to examine its efficacy in the repair of orbital bone defects.Methods The γ-PGA/HEMA/PEG polymeric cryogel was prepared by the cryogelation technique. Orbital bone defects were prepared on twenty-four New Zealand white rabbit. Three groups were made depending on the implanted materials: (1) blank control group; (2) polymeric cryogel group (Gel group); (3) mineralized polymeric cryogel group (M-gel group). Specimens were taken 8 weeks and 16 weeks after implantation for gross observation, micro-computed tomography (μ-CT) and hard tissue grinding slices and tissue sections were used to observe the osteogenesis outcome.Results Radiographic results showed that the mineralized cryogel could effectively facilitate the repair of the orbital bone defect completely, with the defective area completely replaced by bone tissue. Histological results proved that the mineralized polymeric cryogel scaffolds could increase the expression of runt-related transcription factor 2 (Runx-2), alkaline phosphatase (ALP), osteopontin (OPN), and platelet endothelial cell adhesion molecule-1 (CD31), which indicated the strengthened angiogenesis and osteogenic capability after the mineralized cryogel transplantation.Conclusion The mineralized polymeric cryogel served as a potential engineering scaffold in the repair of orbital bone defects via angiogenesis and osteogenesis.

Abstract:Objective Biosensors with multilayer biomedia are widely applied in various fields, and quantitative characterization of biosensors is still a problem for the development of sensors. This study is to quantitatively characterize the electrical properties of multilayer biomedia.Methods Combined with conformal mapping theory, the quantitative characteristics of biosensors are explored based on electrical impedance spectroscopy for clarifying the law of influence on impedance, and this study provides a basic theory for the characterization of biosensors. The impedance (Z^*) of each biomedia layer is extracted, and the simulation and calculation are executed to study the correctness.Results An experimental system has been established, results show that the impedance (Z^*) of the detection area continues to rise from the frequency (f) = 0.1 MHz to f=50.0 MHz in the coating process. This trend is explained that the solution in the original detection area is covered by the coating of biological medium with different dielectric properties, resulting in a decrease in the conductivity of the detection area and an increase in the impedance. Theoretical calculation results and simulation results show a great agreement with experimental results.Conclusion This study confirms that the multilayer biosensors are able to be quantitatively characterized based on electrical impedance spectroscopy and conformal mapping, which has certain practical value for the further development of biosensors.

Abstract:Objective Electrical impedance tomography (EIT) was applied to study the electrical characteristics of human calf muscles under neuromuscular electrical stimulation (NMES), with the objective of using EIT as a long-term monitoring method to visualize the effectiveness of NMES training on human calf muscles.Methods Sixteen subjects were randomly assigned to a control group (CG, n=8), which kept a normal lifestyle and without NMES or other muscle training; an optimal voltage intensity training group (OG, n=8), in which 23 min of NMES training was performed on the right calf using commercial NMES equipment 3 times a week for 5 weeks. EIT was applied to obtain the conductivity distribution before the start of each training cycle on Monday. Bioelectrical impedance analysis (BIA) was also used to measure the extracellular volume ratio (ECW/TBW) β_rl in the right leg.Results In the CG, subjects showed no significant differences in the electrical characteristics of right calf muscle and in the extracellular volume of right calf compared to the first week. However, in the OG, subjects showed the same tendency of increase in the spatial-mean conductivity <σ>_M1 of right calf muscle M₁ muscle compartment and β_rl of right leg compared to the first week.Conclusion NMES training caused an increase in the stimulated muscle compartment spatial-mean conductivity <σ>_M1, with the most dramatic increase in <σ^w2>_M1 of second week, followed by an increase in the third, fourth and fifth weeks compared to the previous week with less growth rate. This implies that a significant increase in muscle fiber volume and sarcoplasmic hypertrophy occurred in the second week, after which the subjects gradually adapted to NMES training and the physiological response of the muscle slowed but continued to grow.

Abstract:Objective Giving up arises when an animal repeats a behavior to avoid danger or to obtain reward without success. It is a common and fundamental behavior that has been extensively studied in model animals such as mice, but the underlying neural mechanisms have not yet been well elucidated. Zebrafish larvae are important model organisms in neuroscience due to their suitability for whole brain imaging. Negative stimuli such as continuous electric shock have been used to induce giving up behavior in zebrafish, however, whether reward stimuli can induce giving up in zebrafish has not been reported.Methods By presenting larval zebrafish visual stimuli of paramecium, the hunting behavior of zebrafish on virtual food was examined, and the changes of the zebrafish predation frequency and predation duration over time were compared.Results Virtual visual stimulation of food can induce the predatory behavior of zebrafish. After receiving virtual stimuli for 25 min, the predation frequency and single predation duration of over 8 days post fertilization (dpf) zebrafish decreased significantly.Conclusion Our study enriches the paradigm of zebrafish give up behavior. The experimental results show that virtual food stimuli lacking real rewards can induce zebrafish to abandon predation. The current behavioral paradigm provides a new method to study animal give up behavior and the underlying neural mechanisms.

Abstract:Objective Understanding the dynamics of protein adsorption at the aqueous gold interface is key to advancing the development of many applications based on gold nanostructures such as plasmonic sensors and biomedical materials. However, the protein conformation in metallic nano-slits has not been fully studied. In this paper, the spacing effect of protein conformation changes in gold nano-slits is studied by building gold atomic layers with different nano-slits using molecular dynamics simulations.Methods We used GOIP-CHARMM force fields with GROMACS to simulate the dynamics of Aβ1-42 protein monomers between Au(111) gold atomic interfaces to study the dynamics of Aβ protein and conformational changes in aqueous environments, 5.0 nm nano-slit, 5.5 nm nano-slit and 8.5 nm nano-slit.Results When the nano-slit spacing is increased from 5.0 nm to 8.5 nm, the interaction of Aβ protein with the gold interface is varied from double-interface adsorption, single-side interface adsorption to no adsorption.Conclusion The interaction of Aβ protein with the metallic interface is greatly affected by the spacing of gold nano-slits. As the slit spacing and the distance of the protein from the interface changes, the protein could exhibit 3 distinct states: single-side surface adsorption, two interface adsorption and no adsorption. We anticipate that the dynamic features of protein adsorption to Au(111) interfaces of nano-slits showed in this work can be extended to other nanostructures and proteins. The results could find applications in design of biosensors for diagnosis of Alzheimer’s disease.

Abstract:Objective To study the spatial correlation of the nerve fibers and blood vessels in the auricular skin by using the combination of histological staining technique and tissue clearing strategy.Methods The anterior and posterior auricular skins were carefully peeled away from the intervening cartilage and the auricular nerve fibers and blood vessels were directly immunofluorescent stained with protein gene product 9.5 (PGP 9.5) and phalloidin followed with tissue clearing treatment. After that, these auricular skins were mounted on the microscope slide in the whole mount pattern and examined under an epifluorescence microscope and a laser scanning confocal microscope.Results It was shown that the PGP 9.5+ nerve fibers aligning with phalloidin-labeled blood vessels ran from the base part of auricle to its peripheral region, forming the neurovascular network in the auricular skin. Beyond the conventional immunofluorescence staining, the additional tissue clearing treatment demonstrated the auricular nerve fibers and blood vessels better in morphological detail.Conclusion From the perspective of methodology, tissue clearing technique enhance the visualization of the immunofluorescence labeling within the auricular skin, which should be an effective approach for insight into the auricular neurovascular network in a three-dimensional view under the physiological and pathological conditions.

Abstract:Objective The online detection of thrombus and visualization are of great importance in the extracorporeal circulatory system. In this paper, a noninvasive and online detection method of thrombus in extracorporeal circulation based on electrical impedance tomography (EIT) is proposed.Methods Firstly, this paper investigates the effect of sensor size on the imaging performance through joint simulation. Secondly, a 16-copper electrode EIT sensor with a diameter of 20 mm is designed based on the simulation results, a cyclic flow experimental platform is built, and static and cyclic flow experiments are designed. Instead of thrombus, pig blood clots of 3-6 mm in size are placed in fresh pig blood samples and image using the Tikhonov regularization algorithm. The 3 mm and 5 mm clots are placed in the circulation system, and the images of the size and position of the clots in the sensor section are reconstructed by the EIT system and compared with the results taken by the high-speed camera.Results The simulation results show that the image correlation coefficients (IC) are greater than 0.06 for the sensor diameters of 20 mm and 30 mm when the target-to-sensor area ratio (AR) is not less than 0.01, and the imaging effect is well. The static imaging results show that the relative size coverage ratio is less than or equal to 0.1. The circulating flow experiments show that the normalized relative conductivity value changes of 80 and 200 are detected as the clots pass through the sensor, and the results show that the method is capable of detecting clots in the circulatory system.Conclusion The method has the advantages of real-time and noninvasive, and is expected to be applied to the detection of thrombus in vitro.

Abstract:Objective Single-cell growth detection can more scientifically reveal the rules of microbial metabolic changes and guide later microbial engineering applications. To study the accurate detection of microbial growth during the food safety period and optimal edible period, a single-cell growth detection method based on Raman technology is proposed in this paper.Methods First, a total of 900 single-cell Raman spectroscopy (SCRS) data were collected from two batches of Bacillus subtilis through a simultaneous culture experiment, of which 600 were used for training and testing and the other 300 for model validation. Secondly, based on the feature relationship matrix of principal component analysis, CP-SP feature evaluation method was proposed to screen SCRS features for model detection. Then, a detection model based on XGBoost was built, and grid search and cross-validation were applied to optimize the detection model. Finally, confusion matrix and ROC curve were used to evaluate the detection accuracy, sensitivity and specificity of the model for cell lag phase, log phase and stationary phase.Results The experiment found that the classification performance of the first, second, and fourth principal components screened by CP-SP was improved by 3.1% compared with the first three principal components of the feature contribution rate. The test accuracy of the optimized cell growth detection model was 96.0%, and the verification accuracy was 92.3%.Conclusion The results show that the single-cell growth detection method based on Raman technology can accurately identify the single-cell growth state and has a high generalization ability, which can provide scientific guidance for the formulation of precise regulatory mechanisms for food safety and preservation.