Desmoglein-3 acts as a pro-survival protein by suppressing reactive oxygen species and doming whilst augmenting the tight junctions in MDCK cells

Kidney disease prevalence increases with age, with a common feature of the disease being defects in the epithelial tight junctions. Emerging evidence suggests that the desmosomal adhesion protein Desmoglein-3 (Dsg3) functions beyond the desmosomal adhesion and plays a role in regulating the fundamental pathways that govern cell fate decisions in response to environmental chemical and mechanical stresses. In this study, we explored the role of Dsg3 on dome formation, reactive oxygen species (ROS) production and transepithelial electrical resistance (TER) in MDCK cells, a kidney epithelial cell model widely used to study cell differentiation and tight junction formation and integrity. We show that overexpression of Dsg3 constrained nuclear ROS production and cellular doming in confluent cell cultures and these features coincided with augmented TER and enhanced tight junction integrity. Conversely, cells expressing dominant-negative Dsg3ΔC mutants exhibited heightened ROS production and accelerated doming, accompanied by increased apoptosis, as well as cell proliferation, with massive disruption in F-actin organization and accumulation, and alterations in tight junctions. Inhibition of actin polymerization and protein synthesis was able to sufficiently block dome formation in mutant populations. Taken together, these findings underscore that Dsg3 has a role in controlling cellular viability and differentiation as well as the functional integrity of tight junctions in MDCK cells.

Recent Developments of High-Resolution Chemical Imaging Systems Based on Light-Addressable Potentiometric Sensors (LAPSs)

A light-addressable potentiometric sensor (LAPS) is a semiconductor electrochemical sensor based on the field-effect which detects the variation of the Nernst potential on the sensor surface, and the measurement area is defined by illumination. Thanks to its light-addressability feature, an LAPS-based chemical imaging sensor system can be developed, which can visualize the two-dimensional distribution of chemical species on the sensor surface. This sensor system has been used for the analysis of reactions and diffusions in various biochemical samples. In this review, the LAPS system set-up, including the sensor construction, sensing and substrate materials, modulated light and various measurement modes of the sensor systems are described. The recently developed technologies and the affecting factors, especially regarding the spatial resolution and temporal resolution are discussed and summarized, and the advantages and limitations of these technologies are illustrated. Finally, the further applications of LAPS-based chemical imaging sensors are discussed, where the combination with microfluidic devices is promising.

A novel bionic in vitro bioelectronic tongue based on cardiomyocytes and microelectrode array for bitter and umami detection

Electronic tongues (ETs) have been developed and widely used in food, beverage and pharmaceutical fields, but limited in sensitivity and specificity. In recent years, bioelectronic tongues (BioETs) integrating biological materials and various types of transducers are proposed to bridge the gap between ET system and biological taste. In this work, a bionic in vitro cell-based BioET is developed for bitter and umami detection, utilizing rat cardiomyocytes as a primary taste sensing element and microelectrode arrays (MEAs) as a secondary transducer for the first time. The primary cardiomyocytes of Sprague Dawley (SD) rats, which endogenously express bitter and umami taste receptors, were cultured on MEAs. Cells attached and grew well on the sensor surface, and syncytium was formed for potential conduction and mechanical beating, indicating the good biocompatibility of surface coating. The specificity of this BioET was verified by testing different tastants and bitter compounds. The results show that the BioET responds to bitter and umami compounds specifically among five basic tastants. For bitter recognition, only those can activate receptors in cardiomyocytes can be recognized by the BioET, and different bitter substances could be discriminated by principal component analysis (PCA). Moreover, the specific detections of two bitters (Denatonium Benzoate, Diphenidol) and an umami compound (Monosodium Glutamate) were realized with a detection limit of 10^-6 M. The cardiomyocytes-based BioET proposed in this work provides a new approach for the construction of BioETs and has promising applications in taste detection and pharmaceutical study.

In-situ detection of cadmium with aptamer functionalized gold nanoparticles based on smartphone-based colorimetric system

Cadmium is a heavy metal pollutant in environment with high toxicity that severely threats human health. A simple and sensitive method for rapid detection of cadmium ions in water sample is of significant importance. In this paper, a colorimetric method based on aptamer-functionalized gold nanoparticles (AuNPs) for specific recognition were proposed to realize Cd²⁺ detection. AuNPs aggregate in high-salt solutions because of the shielding of salt to electrostatic repulsion among AuNPs, while aptamers can strengthen the stability of AuNPs and avoid the aggregation. After adding Cd²⁺ ions, the specific interaction between aptamers and Cd²⁺ leads to a decrease of free aptamers, which weakens the stability of the AuNPs and results in the color change of the solution. The colorimetric change can be rapidly captured and analyzed by a self-developed smartphone-based colorimetric system (SBCS) within 10 min, which implements the quantitative detection of Cd²⁺. The results show that Cd²⁺ ions can be detected with high selectivity and sensitivity with a linear range of 2-20 μg/L and a detection limit of 1.12 μg/L. Compared with other methods, the proposed approach features high sensitivity, high simplicity, easy implementation and high throughout, which provides a promising means for in-situ determination of Cd²⁺ in practical applications.

Interface Modulation of Two-Dimensional Superlattices for Efficient Overall Water Splitting

Molecular-scale modulation of interfaces between different unilamellar nanosheets in superlattices is promising for efficient catalytic activities. Here, three kinds of superlattices from alternate restacking of any two of the three unilamellar nanosheets of MoS₂, NiFe-layered double hydroxide (NiFe-LDH), and graphene are systematically investigated for electrocatalytic water splitting. The MoS₂/NiFe-LDH superlattice exhibits a low overpotential of 210 and 110 mV at 10 mA cm^-2 for oxygen evolution reaction (OER) and alkaline hydrogen evolution reaction (HER), respectively, superior than MoS₂/graphene and NiFe-LDH/graphene superlattices. High activity and stability toward the overall water splitting are also demonstrated on the MoS₂/NiFe-LDH superlattice bifunctional electrocatalyst, outperforming the commercial Pt/C-RuO₂ couple. This outstanding performance can be attributed to optimal adsorption energies of both HER and OER intermediates on the MoS₂/NiFe-LDH superlattice, which originates from a strong electronic coupling effect at the heterointerfaces. These results herald the interface modulation of superlattices providing a promising approach for designing advanced electrocatalysts.

A visible and near-infrared, dual emission fluorescent probe based on thiol reactivity for selectively tracking mitochondrial glutathione in vitro

The precise detection of endogenous biothiols such as Glutathione (GSH), Cysteine (Cys) and Homocysteine (HCy) is a long-standing human health concern. A dual-channel fluorescent probe (Cy-DC) composed of two fluorescence reporting units (dicyanomethylene-4H-pyran and cyanine) with ether linker for distinguishing different endogenous biothiols was designed and synthesized. Due to the two well-resolved emission bands, this probe possesses an outstanding capability for selectively sensing of endogenous GSH spatiotemporally and synchronously. Nevertheless, in the near infrared (NIR) channel (λ_ex = 700 nm, λ_em = 810 nm), the probe can produce strong fluorescence only when it responds to GSH. Besides, the cells (L02 and U87) imaging, it also demonstrated that Cy-DC could successfully discriminate between GSH and Cys/Hcy with high sensitivity with the limit of detection (LOD) is 24 nM and 32 nM (3*SD/K). Particularly, the probe was applied in detecting solid tumor by the naked-eye and NIR imaging successfully, which revealed that the probe has promising prospects in clinical diagnosis applications.

Heterostructured NiFe oxide/phosphide nanoflakes for efficient water oxidation

To realise the gradual replacement of noble metal-based materials for electrocatalytic energy conversion, numerous studies need to be focused on the compounds based on inexpensive 3d transition metals (such as Fe and Co). For achieving energetic electrocatalysis, elaborately designed nanostructures are urgently desired. Here, we reported a facile approach for the preparation of a NiFe oxide/phosphide (Ni_2/3Fe_1/3O/Ni_4/3Fe_2/3P) heterostructure with a 2-dimensional (2D) nanoflake-like morphology. Based on the combined advantages of composition and structure, the 2D Ni_2/3Fe_1/3O/Ni_4/3Fe_2/3P nanoflakes were characterized to exhibit a high activity for the electrocatalytic water oxidation, surpassing that of individual Ni_2/3Fe_1/3O or Ni_4/3Fe_2/3P nanoplates. This result may offer a great possibility of delicatedly designing nanostructures for highly efficient electrochemical energy conversion.

Molecular imaging in the second near-infrared window

In the past decade, noticeable progress has been achieved regarding fluorescence imaging in the second near-infrared (NIR-II) window. Fluorescence imaging in the NIR-II window demonstrates superiorities of deep tissue penetration and high spatial and temporal resolution, which are beneficial for profiling physiological processes. Meanwhile, molecular imaging has emerged as an efficient tool to decipher biological activities on the molecular and cellular level. Extending molecular imaging into the NIR-II window would enhance the imaging performance, providing more detailed and accurate information of the biological system. In this progress report, selected achievements made in NIR-II molecular imaging are summarized. The organization of this report is based on strategies underlying rational designs of NIR-II imaging probes and their applications in molecular imaging are highlighted. This progress report may provide guidance and reference for further development of functional NIR-II probes designed for high-performance molecular imaging.

Graphene-Based Sensors for Human Health Monitoring

Since the desire for real-time human health monitoring as well as seamless human-machine interaction is increasing rapidly, plenty of research efforts have been made to investigate wearable sensors and implantable devices in recent years. As a novel 2D material, graphene has aroused a boom in the field of sensor research around the world due to its advantages in mechanical, thermal, and electrical properties. Numerous graphene-based sensors used for human health monitoring have been reported, including wearable sensors, as well as implantable devices, which can realize the real-time measurement of body temperature, heart rate, pulse oxygenation, respiration rate, blood pressure, blood glucose, electrocardiogram signal, electromyogram signal, and electroencephalograph signal, etc. Herein, as a review of the latest graphene-based sensors for health monitoring, their novel structures, sensing mechanisms, technological innovations, components for sensor systems and potential challenges will be discussed and outlined.

Light-sheet microscopy in the near-infrared II window

Non-invasive deep-tissue three-dimensional optical imaging of live mammals with high spatiotemporal resolution is challenging owing to light scattering. We developed near-infrared II (1,000-1,700 nm) light-sheet microscopy with excitation and emission of up to approximately 1,320 nm and 1,700 nm, respectively, for optical sectioning at a penetration depth of approximately 750 μm through live tissues without invasive surgery and at a depth of approximately 2 mm in glycerol-cleared brain tissues. Near-infrared II light-sheet microscopy in normal and oblique configurations enabled in vivo imaging of live mice through intact tissue, revealing abnormal blood flow and T-cell motion in tumor microcirculation and mapping out programmed-death ligand 1 and programmed cell death protein 1 in tumors with cellular resolution. Three-dimensional imaging through the intact mouse head resolved vascular channels between the skull and brain cortex, and allowed monitoring of recruitment of macrophages and microglia to the traumatic brain injury site.

A genetic variant in PIK3R1 is associated with pancreatic cancer survival in the Chinese population

Pancreatic cancer is one of the deadliest malignancies with few early detection tests or effective therapies. PI3K-AKT signaling is recognized to modulate cancer progression. We previously identified that a genetic variant in PKN1 increased pancreatic cancer risk through the PKN1/FAK/PI3K/AKT pathway. In order to investigate the associations between genetic variations in that pathway and pancreatic cancer prognosis, we conducted a two-stage survival analysis in a total of 547 Chinese pancreatic cancer patients. Consequently, a variant, rs13167294 A>C in PIK3R1, was significantly associated with poor survival in both stages and with hazard ratio being 1.32 (95% CI = 1.13-1.56, P = 0.0007) in the combined analysis. Function annotation and prediction suggested that genetic variants in this locus might affect overall survival of pancreatic cancer patients by regulating PIK3R1 expression.

2D Free-Standing Nitrogen-Doped Ni-Ni3 S2 @Carbon Nanoplates Derived from Metal-Organic Frameworks for Enhanced Oxygen Evolution Reaction

2D metal-organic frameworks (2D MOFs) are promising templates for the fabrication of carbon supported 2D metal/metal sulfide nanocomposites. Herein, controllable synthesis of a newly developed 2D Ni-based MOF nanoplates in well-defined rectangle morphology is first realized via a pyridine-assisted bottom-up solvothermal treatment of NiSO₄ and 4,4'-bipyridine. The thickness of the MOF nanoplates can be controlled to below 20 nm, while the lateral size can be tuned in a wide range with different amounts of pyridine. Subsequent pyrolysis treatment converts the MOF nanoplates into 2D free-standing nitrogen-doped Ni-Ni₃ S₂ @carbon nanoplates. The obtained Ni-Ni₃ S₂ nanoparticles encapsulated in the N-doped carbon matrix exhibits high electrocatalytic activity in oxygen evolution reaction. A low overpotential of 284.7 mV at a current density of 10 mA cm^-2 is achieved in alkaline solution, which is among the best reported performance of substrate-free nickel sulfides based nanomaterials.

Association of C-peptide with diabetic vascular complications in type 2 diabetes

AIM

Fasting serum C-peptide is a biomarker of insulin production and insulin resistance, but its association with vascular complications in type 2 diabetes mellitus (T2DM) has never been fully elucidated. This study aimed to investigate whether C-peptide is associated with cardiovascular disease (CVD) and diabetic retinopathy (DR).

METHODS

A total of 4793 diabetes patients were enrolled from seven communities in Shanghai, China, in 2018. CVD was defined as a self-reported combination of previous diagnoses, including coronary heart disease, myocardial infarction and stroke. DR was examined using fundus photographs. Logistic regression analyses were performed, and multiple imputed data were used to obtain stabilized estimates.

RESULTS

Prevalence of CVD increased with increasing C-peptide levels (Q1, Q2, Q3 and Q4: 33%, 34%, 37% and 44%, respectively; P_{for trend} < 0.001), whereas DR prevalence decreased with increasing C-peptide quartiles (Q1, Q2, Q3 and Q4: 21%, 19%, 15% and 12%, respectively; P_{for trend} < 0.001). On logistic regression analysis, C-peptide levels were significantly associated with CVD prevalence (1.27, 95% CI: 1.13-1.42; P < 0.001) and C-peptide quartiles (Q1: reference; Q2: 1.31, 95% CI: 1.00-1.70; Q3: 1.53, 95% CI: 1.16-2.01; Q4: 1.76, 95% CI: 1.32-2.34; P_{for trend} < 0.001). Given the interaction between C-peptide and BMI and the association between C-peptide and CVD (P_{for interaction} = 0.015), study participants were divided into two subgroups based on BMI which revealed that the association persisted despite different BMI statuses. However, DR prevalence decreased with increasing C-peptide levels (0.73, 95% CI: 0.62-0.86; P < 0.001) and quartiles (Q1: reference; Q2: 1.00, 95% CI: 0.76-1.33; Q3: 0.69, 95% CI: 0.50-0.94; Q4: 0.51, 95% CI: 0.36-0.72; P_{for trend} < 0.001).

CONCLUSION

C-peptide was positively associated with CVD, but inversely associated with DR progression. The association between C-peptide and CVD could be due to associated metabolic risk factors.

Post-synthesis isomorphous substitution of layered Co-Mn hydroxide nanocones with graphene oxide as high-performance supercapacitor electrodes

Layered metal hydroxides are promising materials for electrochemical energy conversion and storage. Generally, compared with layered monometallic hydroxides, layered bimetallic hydroxides have more excellent electrochemical performance due to abundant redox reactions. Unfortunately, layered bimetallic hydroxides cannot be usually achieved through coprecipitation and/or homogeneous precipitation. Herein, we demonstrate that layered Co-Mn hydroxide nanocones (NCs) can be successfully fabricated via post-synthesis isomorphous substitution under mild conditions. In particular, the specific capacity and cycling stability of layered Co-Mn hydroxide NCs are remarkably enhanced in comparison with those of layered Co hydroxide NCs. Furthermore, the resulting layered Co-Mn hydroxide NCs and graphene oxide (GO) composite (GO/Co-Mn NCs) exhibits a high specific capacity of 677 C g-1 at 3 A g-1 and an excellent capacity retention of 95% after 2000 cycles. Asymmetric supercapacitor cells employing GO/Co-Mn NCs as the positive electrode and activated carbon (AC) as the negative electrode can achieve a high specific capacity of 189 C g-1 at 3 A g-1. This method provides a viable protocol for constructing efficient electrodes of layered bimetallic hydroxides for sustainable electrochemical energy storage.

Integrated olfaction, gustation and toxicity detection by a versatile bioengineered cell-based biomimetic sensor

The biological olfactory and gustation system can discriminate thousands of odor and taste substances with high sensitivity and specificity, specific receptor proteins play an important role in this process. This study used the human neuroblastoma SH-SY5Y cell line endogenously expressing the human bitter receptor, T2R16. Meanwhile, an olfactory receptor, ODR-10, was transfected on the plasma membrane of SH-SY5Y cells. T2R16 could specifically respond to bitter compounds with the structure of β-glucopyranosides by activation of G protein coupled receptors (GPCRs) causing cell morphologic changes, which could be monitored using a cell-impedance sensor. ODR-10 could specifically respond to diacetyl by changing the extracellular potential of the cells, the resopnse was recorded by a microelectrode array (MEA). The cell index (CI) value and firing rates were extracted from the signals as the biosensor response characteristics. The results with the sensors indicated a dose-dependent response within a defined concentration range. Moreover, this cell-impedance biosensor enabled quick toxicity detection of salicin when the concentration was ≥6 mM. In conclusion, the biomimetic sensors integrated olfaction, gustation and toxicity detection using the same cell, and has showed great potential for use in both basic research and practical applications.

Positioning, Navigation, and Book Accessing/Returning in an Autonomous Library Robot using Integrated Binocular Vision and QR Code Identification Systems

With rapid advancements in artificial intelligence and mobile robots, some of the tedious yet simple jobs in modern libraries, like book accessing and returning (BAR) operations that had been fulfilled manually before, could be undertaken by robots. Due to the limited accuracies of the existing positioning and navigation (P&N) technologies and the operational errors accumulated within the robot P&N process, however, most of the current robots are not able to fulfill such high-precision operations. To address these practical issues, we propose, for the first time (to the best of our knowledge), to combine the binocular vision and Quick Response (QR) code identification techniques together to improve the robot P&N accuracies, and then construct an autonomous library robot for high-precision BAR operations. Specifically, the binocular vision system is used for dynamic digital map construction and autonomous P&N, as well as obstacle identification and avoiding functions, while the QR code identification technique is responsible for both robot operational error elimination and robotic arm BAR operation determination. Both simulations and experiments are conducted to verify the effectiveness of the proposed technique combination, as well as the constructed robot. Results show that such a technique combination is effective and robust, and could help to significantly improve the P&N and BAR operation accuracies, while reducing the BAR operation time. The implemented autonomous robot is fully-autonomous and cost-effective, and may find applications far beyond libraries with only sophisticated technologies employed.

A bioinspired in vitro bioelectronic tongue with human T2R38 receptor for high-specificity detection of N-C=S-containing compounds

Detection and identification of bitter compounds draw great attention in pharmaceutical and food industry. Several well-known agonists of specific bitter taste receptors have been found to exhibit anti-cancer effects. For example, N-C=S-containing compounds, such as allyl-isothiocyanates, have shown cancer chemo-preventive effects. It is worth noting that human T2R38 receptor is specific for compounds containing N-C=S moiety. Here, a bioinspired cell-based bioelctronic tongue (BioET) is developed for the high-specificity isothiocyanate-induced bitter detection, utilizing human Caco-2 cells as a primary sensing element and interdigitated impedance sensor as a secondary transducer. As an intestinal carcinoma cell line, Caco-2 endogenously expresses human bitter receptor T2R38, and the activation of T2R38 induces the changes of cellular morphology which can be detected by electric cell-substrate impedance sensing (ECIS). After configuration and optimization of parameters including timing of compound administration and cell density, quantitative bitter evaluation models were built for two well-known bitter compounds, phenylthiocarbamide (PTC) and propylthiouracil (PROP). The bitter specific detection of this BioET is inhibited by probenecid and U-73122, and is not elicited by other taste modalities or bitter ligands that do not activate T2R38. Moreover, by combining different computational tools, we designed a ligand-based virtual screening (LBVS) protocol to select ligands that are likely to activate T2R38 receptor. Three computationally predicted agonists of T2R38 were selected using the LBVS protocol, and the BioET presented response to the predicted agonists, validating the capability of the LBVS protocol. This study suggests this unique cell-based BioET paves a general and promising way to specifically detect N-C=S-containing compounds that can be used for pharmaceutical study and drug development.

A theranostic agent for cancer therapy and imaging in the second near-infrared window

Theranostic nanoparticles are integrated systems useful for simultaneous diagnosis and imaging guided delivery of therapeutic drugs, with wide ranging potential applications in the clinic. Here we developed a theranostic nanoparticle (~ 24 nm size by dynamic light scattering) p-FE-PTX-FA based on polymeric micelle encapsulating an organic dye (FE) fluorescing in the 1,000-1,700 nm second near-infrared (NIR-II) window and an anti-cancer drug paclitaxel. Folic acid (FA) was conjugated to the nanoparticles to afford specific binding to molecular folate receptors on murine breast cancer 4T1 tumor cells. In vivo, the nanoparticles accumulated in 4T1 tumor through both passive and active targeting effect. Under an 808 nm laser excitation, fluorescence detection above 1,300 nm afforded a large Stokes shift, allowing targeted molecular imaging tumor with high signal to background ratios, reaching a high tumor to normal tissue signal ratio (T/NT) of (20.0 ± 2.3). Further, 4T1 tumors on mice were completed eradicated by paclitaxel released from p-FE-PTA-FA within 20 days of the first injection. Pharmacokinetics and histology studies indicated p-FE-PTX-FA had no obvious toxic side effects to major organs. This represented the first NIR-II theranostic agent developed.

Rational design of a super-contrast NIR-II fluorophore affords high-performance NIR-II molecular imaging guided microsurgery

In vivo molecular imaging in the "transparent" near-infrared II (NIR-II) window has demonstrated impressive benefits in reaching millimeter penetration depths with high specificity and imaging quality. Previous NIR-II molecular imaging generally relied on high hepatic uptake fluorophores with an unclear mechanism and antibody-derived conjugates, suffering from inevitable nonspecific retention in the main organs/skin with a relatively low signal-to-background ratio. It is still challenging to synthesize a NIR-II fluorophore with both high quantum yield and minimal liver-retention feature. Herein, we identified the structural design and excretion mechanism of novel NIR-II fluorophores for NIR-II molecular imaging with an extremely clean background. With the optimized renally excreted fluorophore-peptide conjugates, superior NIR-II targeting imaging was accompanied by the improved signal-to-background ratio during tumor detection with reducing off-target tissue exposure. An unprecedented NIR-II imaging-guided microsurgery was achieved using such an imaging platform, which provides us with a great preclinical example to accelerate the potential clinical translation of NIR-II imaging.

Severe Gastric Mycormycosis Infection Followed by Cytomegalovirus Pneumonia in a Renal Transplant Recipient: A Case Report and Concise Review of the Literature

Mucormycosis is an uncommonly encountered fungal infection in solid-organ transplantation, occurring most often gastrointestinally. The most common and fatal infectious disease is cytomegalovirus (CMV) pneumonia, which may result in acute respiratory distress syndrome (ARDS), with rapid onset. Early diagnosis, active treatment, and rational reduction of immunosuppressants are crucial for successful kidney transplantation. We performed successful treatment for both mucormycosis and CMV pneumonia and adjusted the tacrolimus dose accordingly. The case we describe was that of a 47-year-old woman with history of renal transplantation 1 month earlier. She presented with chest pain and gastrointestinal bleeding and was diagnosed with gastric mucormycosis and a secondary episode of hospital-acquired pneumonia. Preemptive therapy, which included liposomal amphotericin B and posaconazole, was adminstered when voriconazole proved to be unhelpful and before histologic reports of gastric mucormycosis. Moreover, CMV re-activation was confirmed by CMV antibody detection, and we administered gancyclovir and thymosin α1 but reduced the strength of the immunosuppressive drugs. Fourteen days after the aforementioned therapy, the patient began to recover and she was discharged on day 81 postoperatively. We conclude that preemptive treatment is critical for severe infection in renal transplant recipients, especially with the rarely seen gastric mucormycosis and with ARDS. In addition, immunoregulated agents, such as asthymosin α1, are also of great value in renal transplant recipients in the setting of opportunistic pathogen infections.