Photo- and Humidity-Responsive Liquid Crystal Copolymer Actuators Fabricated via Vapor-Assisted Alignment.

Deformable liquid crystal polymers (LCPs) driven by more than one external stimulus have received extensive attention in fields ranging from multifunctional soft robots to bionic actuators. Combining responsive liquid crystal with nonmesogenic responsive groups within polymer offers a versatile way to obtain multiresponsive LCPs. However, the incorporation of nonmesogenic responsive groups causes interruption in the assembly of mesogens and brings a challenge to the alignment of LCPs. Herein, a new method is put forward to facilitate uniform mesogen alignment by exerting water vapor in the film preparation process. Using this method, vapor-assisted alignment, the homeotropic alignment of azobenzene mesogens is achieved in a copolymer containing nonmesogenic poly(ethylene glycol) (PEG). The obtained copolymer films present photodeformation brought by azobenzene isomerization and humidity-responsive deformation resulting from the asymmetric swelling of film surfaces. The dual-responsive smart "blinds" and bionic flower actuators are fabricated to demonstrate the integration of the two different stimuli. This work is anticipated to provide a feasible alignment method for multiresponsive LCPs, showing the potential applications in soft robots, sensors, and biomimetic devices.

Designing carbon nanotube sponge/Au@MgO2 for surface-enhanced Raman scattering detection and fenton-like degradation of organic pollutants.

With the acceleration of industry and agriculture process, the massive emission of organic pollutants is a major problem which seriously restricts the sustainable development of society. Rapid enrichment, efficient degradation and sensitive detection are three key steps to solve the problem of organic pollutants, while developing a simple method integrating the above three capabilities is still a challenge. Herein, a three-dimensional carbon nanotube sponge decorated with magnesium peroxide and gold nanoparticles (CNTs/Au@MgO2 sponge) was prepared for surface enhanced Raman scattering (SERS) detection and degradation of aromatic organics by advanced oxidation processes. The CNTs/Au@MgO2 sponge with porous structures adsorbed molecules rapidly through π-π and electrostatic interaction, thus more aromatic molecules were driven to the hot-spot areas for highly sensitive SERS detection. A detection of limit with 9.09 × 10-9 M was achieved for rhodamine B (RhB). The adsorbed molecules were degraded by an advanced oxidation process utilizing hydrogen peroxide produced by MgO2 nanoparticles under acidic condition with 99% efficiency. In addition, the CNTs/Au@MgO2 sponge exhibited high reproducibility with the relative standard deviation (RSD) at 1395 cm-1 of approximately 6.25%. The results showed the sponge can be used to effectively track the concentration of pollutants during the degradation process and maintain the SERS activity by re-modifying Au@MgO2 nanomaterials. Furthermore, the proposed CNTs/Au@MgO2 sponge demonstrated the simultaneous functions of enrichment, degradation, and detection for aromatic pollutants, thus significantly expanding the potential applications of nanomaterials in environmental analysis and treatment.

Effect of Cu loading content on the catalytic performance of Cu-USY catalysts for selective catalytic reduction of NO with NH3.

Series of Cu-USY zeolite catalyst with different Cu loading content were synthesized through simple impregnation method. The obtained catalysts were subjected to selective catalytic reduction of NOx with NH3 (NH3-SCR) performance evaluation, structural/chemical characterizations such as X-ray diffraction (XRD), N2 adsorption/desorption, H2 temperature-programmed reduction (H2-TPR), NH3 temperature-programmed desorption (NH3-TPD) as well as detailed in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments including CO adsorption, NH3 adsorption and NO+O2 in situ reactions. Results show that Cu-USY with proper Cu loading (in this work 5Cu-USY with 5 wt.% Cu) could be promising candidates with highly efficient NH3-SCR catalytic performance, relatively low byproduct formation and excellent hydrothermal stability, although its SO2 poisoning tolerability needs alleviation. Further characterizations reveal that such catalytic advantages can be attributed to both active cu species and surface acid centers evolution modulated by Cu loading. On one hand, Cu species in the super cages of zeolites increases with higher Cu content and being more conducive for NH3-SCR reactivity. On the other hand, higher Cu loading leads to depletion of Brønsted acid centers and simultaneous formation of abundant Lewis acid centers, which facilitates NH4NO3 reduction via NH3 adsorbed on Lewis acid centers, thus improving SCR reactivity. However, Cu over-introduction leads to formation of surface highly dispersed CuOx, causing unfavorable NH3 oxidation and inferior N2 selectivity.

Potential of Endogenous Oxytocin in Endocrine Treatment and Prevention of COVID-19.

Coronavirus disease 2019 or COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a significant threat to the health of human beings. While wearing mask, maintaining social distance and performing self-quarantine can reduce virus spreading passively, vaccination actively enhances immune defense against COVID-19. However, mutations of SARS-CoV-2 and presence of asymptomatic carriers frustrate the effort of completely conquering COVID-19. A strategy that can reduce the susceptibility and thus prevent COVID-19 while blocking viral invasion and pathogenesis independent of viral antigen stability is highly desirable. In the pathogenesis of COVID-19, endocrine disorders have been implicated. Correspondingly, many hormones have been identified to possess therapeutic potential of treating COVID-19, such as estrogen, melatonin, corticosteroids, thyroid hormone and oxytocin. Among them, oxytocin has the potential of both treatment and prevention of COVID-19. This is based on oxytocin promotion of immune-metabolic homeostasis, suppression of inflammation and pre-existing comorbidities, acceleration of damage repair, and reduction of individuals' susceptibility to pathogen infection. Oxytocin may specifically inactivate SARS-COV-2 spike protein and block viral entry into cells via angiotensin-converting enzyme 2 by suppressing serine protease and increasing interferon levels and number of T-lymphocytes. In addition, oxytocin can promote parasympathetic outflow and the secretion of body fluids that could dilute and even inactivate SARS-CoV-2 on the surface of cornea, oral cavity and gastrointestinal tract. What we need to do now is clinical trials. Such trials should fully balance the advantages and disadvantages of oxytocin application, consider the time- and dose-dependency of oxytocin effects, optimize the dosage form and administration approach, combine oxytocin with inhibitors of SARS-CoV-2 replication, apply specific passive immunization, and timely utilize efficient vaccines. Meanwhile, blocking COVID-19 transmission chain and developing other efficient anti-SARS-CoV-2 drugs are also important. In addition, relative to the complex issues with drug applications over a long term, oxytocin can be mobilized through many physiological stimuli, and thus used as a general prevention measure. In this review, we explore the potential of oxytocin for treatment and prevention of COVID-19 and perhaps other similar pathogens.

Oxytocin in Women's Health and Disease.

Oxytocin (OT) is a nonapeptide mainly produced in the supraoptic and paraventricular nuclei. OT in the brain and blood has extensive functions in both mental and physical activities. These functions are mediated by OT receptors (OTRs) that are distributed in a broad spectrum of tissues with dramatic sexual dimorphism. In both sexes, OT generally facilitates social cognition and behaviors, facilitates parental behavior and sexual activity and inhibits feeding and pain perception. However, there are significant differences in OT levels and distribution of OTRs in men from women. Thus, many OT functions in men are different from women, particularly in the reproduction. In men, the reproductive functions are relatively simple. In women, the reproductive functions involve menstrual cycle, pregnancy, parturition, lactation, and menopause. These functions make OT regulation of women's health and disease a unique topic of physiological and pathological studies. In menstruation, pre-ovulatory increase in OT secretion in the hypothalamus and the ovary can promote the secretion of gonadotropin-releasing hormone and facilitate ovulation. During pregnancy, increased OT synthesis and preterm release endow OT system the ability to promote maternal behavior and lactation. In parturition, cervix expansion-elicited pulse OT secretion and uterine OT release accelerate the expelling of fetus and reduce postpartum hemorrhage. During lactation, intermittent pulsatile OT secretion is necessary for the milk-ejection reflex and maternal behavior. Disorders in OT secretion can account for maternal depression and hypogalactia. In menopause, the reduction of OT secretion accounts for many menopausal symptoms and diseases. These issues are reviewed in this work.

Fabrication of 3D Porous Polyvinyl Alcohol/Sodium Alginate/Graphene Oxide Spherical Composites for the Adsorption of Methylene Blue.

In this study, three-dimensional (3D) networked porous polyvinyl alcohol/sodium alginate/graphene oxide (PVA/SA/GO) spherical composites were fabricated by the sol-gel method and employed as adsorbents for the adsorption of methylene blue (MB) in aqueous solution. The obtained samples were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal property analysis, and nitrogen adsorption/desorption isotherms. Moreover, the adsorption properties for MB were investigated by batch experiments. The pseudo-first-order and pseudo-second-order equations were used to fit the adsorption kinetics data, and the Langmuir and Freundlich isothermal models were used to analyze the adsorption isothermals. The results showed that the spherical composites had 3D porous structures, and GO, PVA and SA were fused and linked together by self-assembly, physical intertwining, hydrogen bonding, and Ca2+ and boric acid crosslinking. The maximum adsorption capacity of the 3D porous PVA/SA/GO spherical composites for MB was 759.3 mg/g. The adsorption kinetics had a better agreement with the pseudo-secondorder equation than the pseudo-first-order equation, and the equilibrium data followed the Freundlich model.

A novel fluorescent and electrochemical dual-responsive immunosensor for sensitive and reliable detection of biomarkers based on cation-exchange reaction.

Sensitive and reliable detection of biomarkers is of vital importance in tumor early detection and clinical therapy. A novel fluorescent/electrochemical dual-responsive immunosensing platform for reliable and sensitive quantification of biomarkers was designed based on cation-exchange reaction. To construct such a versatile platform, the model analyte, carcinoembryonic antigen (CEA), was captured by magnetic Fe3O4 nanoparticles bound with primary antibodies (Fe3O4-Ab1) and then recognized by the detection antibodies conjugated complex containing poly(amidoamine) (PAMAM), carbon nanotube (CNT) and carboxyl functionalized CdSe nanocrystals (NCs) (CNT-PAMAM-CdSe NCs-Ab2). Via ligand exchange, the stable CdSe nanocrystals were easily functionalized with carboxylate ion (CdSe-COO-) and showed high hydrophilicity. The CdSe-COO- was effectively and densely conjugated to CNT coated dendrimer PAMAM that possesses large specific surface area. Finally, the target CEA was detected based on cation-exchange reaction (CER) by adding Ag+ to release thousands of cations Cd2+, which were detected by fluorescence and electrochemistry simultaneously. The electrochemical measurement was performed by directly detecting Cd2+ through square wave voltammetry (SWV), which displayed an excellent correlation with CEA from 5 pg/mL to 50 ng/mL, with a limit of detection (LOD) of 1.7 pg/mL. The fluorescence detection was implemented since free Cd2+ could trigger the weak fluorescence metal-sensitive dyes (Rhod-5N) to generate extremely high fluorescence signal. The fluorescence results showed the LOD for CEA detection was 0.25 pg/mL with a calibration curve range from 1 pg/mL to 20 ng/mL. The dual signal outputs showed an attractively self-correcting ability, which provides the capability of avoiding false positive signal and making the detection result more reliable. The proposed dual-responsive platform holds great promises for biomarkers detection in clinical diagnostics and therapy.

A novel arginine bioprobe based on up-conversion fluorescence resonance energy transfer.

Arginine is an important amino acid in humankind bodies and is of essential clinical significance. This paper presents a novel bioprobe based on fluorescence resonance energy transfer (FRET), which can be used to detect arginine efficiently and economically. In this bioprobe system, positively charged up-conversion phosphor NaYF4 (NYF) acts as energy donor, and negatively charged gold nanoparticle (AuNP) acts as energy acceptor. The oppositely charged donor and acceptor come into close proximity through electrostatic attraction effect, which results in the occurrence of FRET between NYF and AuNP. The FRET process is thus in the "on" state, meanwhile the system is in the "off" state, and the emitting light of NYF quenched. When positively charged arginine is added into the system, the guanidyl of arginine binds to AuNP and leads to the negatively charged AuNP becomes positively charged one, and the AuNP separates from NYF because of the electrostatic repulsion. The FRET process is blocked and the system switches to the "on" state because the distance between NYF and AuNP becomes longer. In the "on" state, the intensity of the restored emitting light is proportional to the concentration of arginine. This approach brings a good linear relationship between the fluorescence intensity and the concentration of arginine in the concentration range of 14.42-115.04 µM. The limit of detection is as low as 2.9 µM. A new method for quantitative determination of arginine by just measuring the fluorescence intensity of the system is established.

Amperometric sarcosine biosensor based on hollow magnetic Pt-Fe3O4@C nanospheres.

Sarcosine is a recently identified biomarker for prostate cancer. However, the rapid detection methods for sarcosine are relatively lack because of the low concentration and the presence of complicated interfering substances in serum or urine. In this manuscript, hollow nanospheres of Fe3O4 was synthesized and used as carrier to disperse Pt (Pt) nanoparticles. In order to achieve excellent electron transfer ability, we use polyaniline to coat Pt-Fe3O4 nanoparticles, and pyrolyze the polyaniline to carbon (C). Thus, hollow magnetic Pt-Fe3O4@C nanocomposites with good electron transfer ability are formed. The Pt-Fe3O4@C nanocomposites have high catalytic activity and stability. The nanocomposites were immobilized on glassy carbon electrode (GCE) to construct a nonenzyme hydrogen peroxide (H2O2) sensor (Pt-Fe3O4@C/GCE). We further construct a sensitive sarcosine biosensor by immobilizing sarcosine oxidase (SOx) on the Pt-Fe3O4@C/GCE. The high catalytic activity and good biocompatibility of Pt-Fe3O4@C nanocomposites greatly retained the bioactivity of immobilized SOx, and the prepared sarcosine biosensor has good electrocatalytic performance towards sarcosine. It has a linear detection range between 0.5 and 60 µM with a limit of detection (LOD) of 0.43 µM (the signal to noise ratio is 3), and the sensitivity is 3.45 nA µM-1 (48.8 nA µM-1 cm-2), which has the potential to be used for rapid screening of prostate cancer.

Rapid and selective detection of Fe (III) by using a smartphone-based device as a portable detector and hydroxyl functionalized metal-organic frameworks as the fluorescence probe.

Here, a label-free fluorescent sensor was developed for detection Fe (III) by utilizing the quenching effect of Fe (III) on the fluorescence of the hydroxyl functionalized metal-organic framework MIL-53(Fe)-(OH)2, which was synthesized by using a one-step solvothermal method. The specific binding interaction between Fe (III) and hydroxyl facilitated the absorption of free Fe (III) to MIL-53(Fe)-(OH)2, which leads to rapid fluorescent intensity quenching effect. The potential quenching mechanism was proved to be the photo-induced electron transfer (PET) from electron-rich ligands of MIL-53(Fe)-(OH)2 to the half-filled 3d orbitals of free Fe (III) in the sample solution. For in-field applications, the fluorescence signal was detected rapidly by using a homemade 3D-printed, portable, and low-cost smartphone sensor. A commercial 365 nm UV LED light was adopted as the excitation light source, while the camera in a smartphone was utilized as the optical detector. The fluorescent signals obtained by using the smartphone sensor were in a good agreement with those obtained from a commercial microplate reader. Under the optimal assay conditions, the linear detection range of Fe (III) was 5.0-200 µM, and the limit of detection is 1.7 µM. This result is compatible with the commercial microplate reader. The developed method was successfully adopted to detect Fe (III) in human serum and environmental water samples with acceptable recovery values of 90-108.5%. The portable, low-cost, fast-response, user-friendly and sensitive fluorescent protocol based on a self-quenching fluorescent nanoprobe can be conducted at home or anywhere else without sophisticated instruments, showing a great application potential in clinical diagnosis, on-site environmental monitoring and healthcare at home.

Amperometric sarcosine biosensor with strong anti-interference capabilities based on mesoporous organic-inorganic hybrid materials.

Amperometric enzyme biosensors are some of the simplest and cheapest types of medical devices used in the rapid detection of biomarkers that have been developed in the past fifty years. When the concentrations of biomarkers are at micromoles per liter, such as for sarcosine, which was recently discovered as a biomarker for prostate cancer, the response signal of the interferences is huge, and the biosensor is hard to satisfy the requirements of practical applications. In this manuscript, we describe a strategy for synthesizing a surface electronegative organic-inorganic hybrid mesoporous material, which could reduce the interference signal much better than Nafion and Chitosan. We verify that the surface potential of the carrier nanomaterial plays an important role in excluding anionic interferences. We also prepare a sensitive (16.35 µA mM-1), low LOD (0.13 µM) and wide linear range (1-70 µM) amperometric sarcosine biosensor with excellent anti-interference properties. This mesoporous material provides a bio-composite platform for the development of simple amperometric biosensors for detecting micromoles per liter of analytes in serum or urine.

Therapeutic Potential of Oxytocin in Atherosclerotic Cardiovascular Disease: Mechanisms and Signaling Pathways.

Coronary artery disease (CAD) is a major cardiovascular disease responsible for high morbidity and mortality worldwide. The major pathophysiological basis of CAD is atherosclerosis in association with varieties of immunometabolic disorders that can suppress oxytocin (OT) receptor (OTR) signaling in the cardiovascular system (CVS). By contrast, OT not only maintains cardiovascular integrity but also has the potential to suppress and even reverse atherosclerotic alterations and CAD. These protective effects of OT are associated with its protection of the heart and blood vessels from immunometabolic injuries and the resultant inflammation and apoptosis through both peripheral and central approaches. As a result, OT can decelerate the progression of atherosclerosis and facilitate the recovery of CVS from these injuries. At the cellular level, the protective effect of OT on CVS involves a broad array of OTR signaling events. These signals mainly belong to the reperfusion injury salvage kinase pathway that is composed of phosphatidylinositol 3-kinase-Akt-endothelial nitric oxide synthase cascades and extracellular signal-regulated protein kinase 1/2. Additionally, AMP-activated protein kinase, Ca2+/calmodulin-dependent protein kinase signaling and many others are also implicated in OTR signaling in the CVS protection. These signaling events interact coordinately at many levels to suppress the production of inflammatory cytokines and the activation of apoptotic pathways. A particular target of these signaling events is endoplasmic reticulum (ER) stress and mitochondrial oxidative stress that interact through mitochondria-associated ER membrane. In contrast to these protective effects and machineries, rare but serious cardiovascular disturbances were also reported in labor induction and animal studies including hypotension, reflexive tachycardia, coronary spasm or thrombosis and allergy. Here, we review our current understanding of the protective effect of OT against varieties of atherosclerotic etiologies as well as the approaches and underlying mechanisms of these effects. Moreover, potential cardiovascular disturbances following OT application are also discussed to avoid unwanted effects in clinical trials of OT usages.

Role of Connexin 36 in Autoregulation of Oxytocin Neuronal Activity in Rat Supraoptic Nucleus.

In the supraoptic nucleus (SON), the incidence of dye coupling among oxytocin (OT) neurons increases significantly in nursing mothers. However, the type(s) of connexin (Cx) involved is(are) unknown. In this study, we specifically investigated whether Cx36 plays a functional role in the coupling between OT neurons in the SON of lactating rats. In this brain region, Cx36 was mainly coimmunostained with vasopressin neurons in virgin female rats, whereas in lactating rats, Cx36 was primarily colocalized with OT neurons. In brain slices from lactating rats, application of quinine (0.1 mM), a selective blocker of Cx36, significantly reduced dye coupling among OT neurons as well as the discharge/firing frequency of spikes/action potentials and their amplitude, and transiently depolarized the membrane potential of OT neurons in whole-cell patch-clamp recordings. However, quinine significantly reduced the amplitude, but not frequency, of inhibitory postsynaptic currents in OT neurons; the duration of excitatory postsynaptic currents was reduced but not their frequency and amplitude. Furthermore, the excitatory effect of OT (1 pM) on OT neurons was significantly weakened and delayed by quinine, and burst firing was absent in the presence of this inhibitor. Lastly, Western blotting analysis revealed that the presence of combined, but not alone, quinine and OT significantly reduced the amount of Cx36 in the SON. Thus, Cx36-mediated junctional communication plays a crucial role in autoregulatory control of OT neuronal activity, likely by acting at the postsynaptic sites. The level of Cx36 is modulated by its own activity and the presence of OT.

CdTe@SiO2 signal reporters-based fluorescent immunosensor for quantitative detection of prostate specific antigen.

In this paper, an immunosensor using CdTe@SiO2 core-shell nanoparticles as labels was constructed for highly sensitive detection of prostate-specific antigen (PSA). In this approach, CdTe@SiO2 core-shell nanoparticles were synthesized using the sol-gel method. The additional Cd ions and sulfur source in SiO2 shell can greatly enhance the fluorescence intensity of CdTe nanocrystals. The reason is the formation of CdS-like cluster in SiO2 shell, which reduced the quantum size effect. The obtained CdTe@SiO2 nanoparticles also exhibited excellent biocompatibility, which was ideal for applying in biomarker detection. Furthermore, PSA capture antibodies functionalized magnetic Fe3O4 nanoparticles (Fe3O4-Ab1) were utilized in the proposed immunosensor to capture and enrich the PSA. The captured PSA was then immuno-recognized by CdTe@SiO2 labeled with PSA detection antibodies (CdTe@SiO2-Ab2) by forming the sandwich complex Fe3O4-Ab1/PSA/Ab2-CdTe@SiO2. The construction of this immunosensor was confirmed by fluorescence spectroscopy. The proposed immunosensor showed a good linear relationship between the fluorescent intensity and the target PSA concentration ranging from 0.01 to 5 ng/mL, and a detection limit as low as 0.003 ng/mL was achieved. The sensor also exhibited good specificity to PSA. This highly sensitive and specific immunosensor has great potential to be used in other biological detection.

Platinum-loaded mesoporous nickel phosphonate and its electrochemical application for sarcosine detection.

In 2009, Sreekumar found that sarcosine, as an effective biomarker, can be used to identify prostate cancer. However, it is difficult to detect sarcosine in urine or plasma because of its low concentration. In this work, we describe a simple strategy for the preparation of sarcosine biosensor based on platinum-loaded mesoporous nickel phosphonate (Pt/MNP) and subsequently apply it to detect sarcosine. Mesoporous structure could increase the active sites on the MNP surface, which makes the Pt/MNP have excellent electrochemical performance for detecting hydrogen peroxide, one of the enzymatic products, and the sarcosine biosensor exhibited a superior electrochemical performance. The linear range of sarcosine biosensor is from 5 to 40 µM and the sensitivity is 123.51 µA mM-1 cm-2. The limit of detection is estimated to be 0.24 µM (S/N = 3). Additionally, the sarcosine biosensor based on Pt/MNP also shows an excellent performance in the anti-interference test and the real serum sample. This work manifests the potential application of Pt/MNP as a novel biosensor material for sarcosine detection, which could be extended to other oxidase-based detection systems.

Exploring the Biocompatibility of Zwitterionic Copolymers for Controlling Macrophage Phagocytosis of Bacteria.

This paper provides a biomaterial derived from zwitterionic polymer for controlling macrophage phagocytosis of bacteria. A series of zwitterionic copolymers, named DMAPS-co-AA, are synthesized with 3-dimethyl (methacryloyloxyethyl) ammonium propane sulfonate (DMAPS) and acrylic acid (AA). The biocompatibility of DMAPS-co-AA copolymers can be adjusted by adjusting the DMAPS-content or pH value. As the DMAPS-content increases, the biocompatibility of zwitterionic copolymer increases. The zwitterionic copolymers with DMAPS content above 30 wt% have higher biocompatibility. Moreover, the biocompatibility also increases significantly as the pH increases from 3.4 to 7.2. By adjusting the pH above 5.8, the zwitterionic copolymer with lower DMAPS-content also shows higher biocompatibility. Importantly, after incubation with the DMAPS-co-AA copolymer solutions at different pH values, phagocytosis behavior of macrophage RAW264.7 cells can also be adjusted. The phagocytosis of bacteria is enhanced at pH = 7.2. Thus, it is proposed that zwitterionic copolymers can be used for controlling phagocytosis of bacteria.

3-D Printed Adjustable Microelectrode Arrays for Electrochemical Sensing and Biosensing.

Printed Electronics has emerged as an important fabrication technique that overcomes several shortcomings of conventional lithography and provides custom rapid prototyping for various sensor applications. In this work, silver microelectrode arrays (MEA) with three different electrode spacing were fabricated using 3-D printing by the aerosol jet technology. The microelectrodes were printed at a length scale of about 15 µm, with the space between the electrodes accurately controlled to about 2 times (30 µm, MEA30), 6.6 times (100 µm, MEA100) and 12 times (180 µm, MEA180) the trace width, respectively. Hydrogen peroxide and glucose were chosen as model analytes to demonstrate the performance of the MEA for sensor applications. The electrodes are shown to reduce hydrogen peroxide with a reduction current proportional to the concentration of hydrogen peroxide for certain concentration ranges. Further, the sensitivity of the current for the three electrode configurations was shown to decrease with an increase in the microelectrode spacing (sensitivity of MEA30: MEA100: MEA180 was in the ratio of 3.7: 2.8: 1), demonstrating optimal MEA geometry for such applications. The noise of the different electrode configurations is also characterized and shows a dramatic reduction from MEA30 to MEA100 and MEA180 electrodes. Further, it is shown that the response current is proportional to MEA100 and MEA180 electrode areas, but not for the area of MEA30 electrode (the current density of MEA30 : MEA100 : MEA180 is 0.25 : 1 : 1), indicating that the MEA30 electrodes suffer from diffusion overlap from neighboring electrodes. The work thus establishes the lower limit of microelectrode spacing for our geometry. The lowest detection limit of the MEAs was calculated (with S/N = 3) to be 0.45 µM. Glucose oxidase was immobilized on MEA100 microelectrodes to demonstrate a glucose biosensor application. The sensitivity of glucose biosensor was 1.73 µAmM-1 and the calculated value of detection limit (S/N = 3) was 1.7 µM. The electrochemical response characteristics of the MEAs were in agreement with the predictions of existing models. The current work opens up the possibility of additive manufacturing as a fabrication technique for low cost custom-shaped MEA structures that can be used as electrochemical platforms for a wide range of sensor applications.

Oxytocin-secreting system: A major part of the neuroendocrine center regulating immunologic activity.

Interactions between the nervous system and immune system have been studied extensively. However, the mechanisms underlying the neural regulation of immune activity, particularly the neuroendocrine regulation of immunologic functions, remain elusive. In this review, we provide a comprehensive examination of current evidence on interactions between the immune system and hypothalamic oxytocin-secreting system. We highlight the fact that oxytocin may have significant effects in the body, beyond its classical functions in lactation and parturition. Similar to the hypothalamo-pituitary-adrenal axis, the oxytocin-secreting system closely interacts with classical immune system, integrating both neurochemical and immunologic signals in the central nervous system and in turn affects immunologic defense, homeostasis, and surveillance. Lastly, this review explores therapeutic potentials of oxytocin in treating immunologic disorders.

Mesoporous Pt Nanotubes as a Novel Sensing Platform for Sensitive Detection of Intracellular Hydrogen Peroxide.

Controlling the shape, structure, and surface morphology of nanomaterials is of great significance in optimizing sensitivity and catalytic performances in biosensing applications. The main goal of employing Pt-based nanomaterials is to increase their utilization efficiency due to their high cost. Herein, we report the synthesis of mesoporous Pt nanotubes using Pluronic P123 as soft templates and Ag nanowires with 50 nm in diameter as hard templates. The resultant materials with unique structures show high sensitivity and stability toward H2O2 detection with low cellular cytotoxicity. The high sensitivity and catalytic properties are attributed to the mesopores and hollow structures making the inner Pt surfaces accessible to reaction media and enlarging the total surface area and one-dimensional structure facilitating the mass diffusion rate.

Nonsocial functions of hypothalamic oxytocin.

Oxytocin (OXT) is a hypothalamic neuropeptide composed of nine amino acids. The functions of OXT cover a variety of social and nonsocial activity/behaviors. Therapeutic effects of OXT on aberrant social behaviors are attracting more attention, such as social memory, attachment, sexual behavior, maternal behavior, aggression, pair bonding, and trust. The nonsocial behaviors/functions of brain OXT have also received renewed attention, which covers brain development, reproduction, sex, endocrine, immune regulation, learning and memory, pain perception, energy balance, and almost all the functions of peripheral organ systems. Coordinating with brain OXT, locally produced OXT also involves the central and peripheral actions of OXT. Disorders in OXT secretion and functions can cause a series of aberrant social behaviors, such as depression, autism, and schizophrenia as well as disturbance of nonsocial behaviors/functions, such as anorexia, obesity, lactation failure, osteoporosis, diabetes, and carcinogenesis. As more and more OXT functions are identified, it is essential to provide a general view of OXT functions in order to explore the therapeutic potentials of OXT. In this review, we will focus on roles of hypothalamic OXT on central and peripheral nonsocial functions.