Nanoreactor based on Cu nanoparticles confined in B, N co-doped porous carbon nanotubes for glutathione biosensing.

A cost-effective approach has been developed to synthesize Cu nanoparticles encapsulated into B and N double-doped carbon nanotubes (Cu@BCNNTs) by one-step pyrolysis. According to the specific binding of Cu-Cl and Cu-glutathione (GSH), we employed Cu@BCNNTs to build an electrochemical sensing platform to detect GSH. The unique space-confined structure can prevent Cu nanoparticles from agglomeration. In addition, B and N co-doped porous hollow tubes can improve the electrochemical conductivity, expand the number of active sites, enhance surface adsorption, and shorten the transport path. These favorable characteristics of Cu@BCNNTs make them have excellent electrocatalytic properties. These results display that the prepared sensor can detect GSH from 0.5 to 120 µM with a detection limit of 0.024 µM. The obtained sensors can be successfully applied in the human serum with recovery of GSH ranging from 100.2 to 103.9%. This work provides a new vision to synthesize nanoparticles confined in a hollow tube for the applications in biosensing and medical diagnostics.

Anxiolytic-like effects of α-asarone in a mouse model of chronic pain.

α-asarone (ASR) is a major bioactive compound isolated from the rhizome of Acorus tatarinowii Schott and it has extensive biological effects. Clinically, anxiety disorder is a common comorbidity of chronic pain. However, limited information is available regarding the effects of ASR on chronic pain-related anxiety. This study aims to evaluate the anxiolytic effects of ASR in chronic pain mice. Chronic inflammatory pain was induced by hind-paw injection of complete Freund's adjuvant (CFA). Behavioral tests, western-blot analysis and whole-cell patch recordings were performed to evaluate the subsequent events. We found that ASR induced anxiolytic activities in CFA-injected mice but did not affect the nociceptive threshold. ASR administration reversed the up-regulation of GluR1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, NR2A-containing N-methyl-D-aspartate (NMDA) receptors and down-regulation of γ-aminobutyric acid A (GABAA) receptors in the basolateral amygdala (BLA) of CFA-injected mice. Electrophysiological data revealed that ASR treatment restored the balance between excitatory and inhibitory neurotransmissions, which was disturbed in the BLA of CFA-injected mice. Moreover, ASR prevented the hyper-excitability of pyramidal neurons in the BLA of chronic pain mice. Our results suggested that the anxiolytic effects of ASR were partially due to maintaining the balance between excitatory/inhibitory transmissions and attenuating neuronal hyper-excitability of excitatory neurons in the BLA.

Candidatus Rickettsia tarasevichiae Infection in Eastern Central China: A Case Series.

BACKGROUND: Human infection with Candidatus Rickettsia tarasevichiae (CRT) was first reported in northeastern China in 2012. OBJECTIVE: To describe the clinical spectrum and laboratory findings of patients infected with CRT in eastern central China. DESIGN: Case series. SETTING: A sentinel hospital for severe fever with thrombocytopenia syndrome (SFTS) in eastern central China in 2014. PARTICIPANTS: Hospitalized patients with SFTS-like illness. MEASUREMENTS: Molecular and serologic tests were performed to diagnose CRT infection. Data about clinical manifestations and laboratory findings were retrieved from medical records. RESULTS: 56 of 733 assessed patients had CRT based on polymerase chain reaction and sequencing. All patients presented with nonspecific manifestations, including fever (96%), malaise (88%), myalgia (57%), cough (25%), and dizziness (14%). Only 2 patients had rash. Further, 16% had eschar, 29% had lymphadenopathy, 100% had gastrointestinal symptoms, 34% had neurologic symptoms, 43% had hemorrhagic manifestations, and 23% had signs of plasma leakage. Thrombocytopenia was observed in 70%, leukopenia in 59%; lymphopenia in 45%; and elevated levels of lactate dehydrogenase in 82%, aspartate aminotransferase in 70%, alanine aminotransferase in 54%, and creatinine kinase in 46%. Co-infection with SFTS virus was documented in 66% patients, and 8 of the 56 patients died. LIMITATIONS: Patients with CRT were not treated for infection because they were retrospectively identified. This was not a population-based study, and the results cannot be generalized to all patients with CRT. CONCLUSION: Candidatus R tarasevichiae infection should be considered in the differential diagnosis of febrile patients with SFTS-like illness in endemic areas. PRIMARY FUNDING SOURCE: National Natural Science Foundation of China.

Electrochemical/fluorescent dual-mode aptasensor based on 3D porous AuNPs/MXene for detection of ultra-trace mercury (Hg2+).

In this work, the dual-mode aptasensor based on 3D porous AuNPs/MXene using "turn-on" electrochemical method and "turn-off" fluorescent strategy was fabricated. Here, 2D MXene was processed into 3D porous MXene by sacrificial polymethylmethacrylate (PMMA) spherical template. And the meteor hammer-like AuNPs which had good electrochemical properties and quenching effect on fluorescence was synthesized by single electrodeposition. Dual-signal labeled Nile Blue (NB) was in situ grafted to the Hg2+ aptamer ends of 3D porous AuNPs/MXene/GCE, and an efficient and sensitive signal interface was constructed to realize the sensitive detection of Hg2+. 3D porous AuNPs/MXene had the advantages of large specific surface area, excellent electron transmission performance and signal amplification. The experimental results indicated that this sensor exhibited high sensitivity to Hg2+ in both electrochemical and fluorescent sensing, with detection limits of 2.69 fM and 1.60 fM, respectively. Further, the dual-mode aptasensor can ensure the detection accuracy and target quantization. The dual-mode aptasensor has been successfully applied to the ultra-trace detection of Hg2+ in actual water samples, which shows the potential of aptamer sensor in detecting heavy metal ions in environmental monitoring.

Catalytic amplification based on hierarchical heterogeneity bimetal-organic nanostructures with peroxidase-like activity.

In this paper, integrating heterometallic units and nanostructures into metal-organic frameworks (MOFs) were applied to improve the sensitivity of detecting hydrogen peroxide (H2O2) in neutral solution. The bimetal-MOFs (CuCo-BDC) and GO composite (CuCo-BDC/GO) were first synthesized via an ordinary one-step solvothermal synthesis. The CuCo-BDC/GO with admirable peroxidase-like catalytic activity could be applied to detect H2O2. The results have low detection limit of 69 nM (S/N = 3) and a wide linear detection range, from 100 nM to 3.5 mM. This is superior to recently published biosensors based on noble metal nanomaterials, which confirms CuCo-BDC/GO as the MOF electrocatalysts with high performance. The remarkable electroanalytical performance of CuCo-BDC/GO is due to the presence of numerous open metal active sites, the synergistic effect of Cu2+ and Co2+, hierarchical structure with high-specific surface areas and the marvelous electrochemical properties of GO. Therefore, CuCo-BDC/GO is a powerful candidate for detecting H2O2 in electrochemical biosensing fields. Moreover, H2O2 detection in real samples can be done with the CuCo-BDC/GO, including human serum samples. Therefore, the novel CuCo-BDC/GO is a promising catalyst that can be applied in biotechnological and environmental applications.