Strong cathode electroluminescence biosensor based on CeO2 functionalized PCN-222@Ag NPs for sensitive detection of p-Tau-181 protein

Electrochemiluminescence (ECL) biosensors provide a convenient and high sensitivity method for early disease diagnosis. However, creating luminophore arrays relying on powerful ECL signals remains a daunting task. Porphyrin-centered metal organic frameworks (MOFs) exhibit remarkable potential in ECL sensing applications. In this paper, based on a simple one-pot synthesis method, PCN-222@Ag NPs doped with CeO2 was synthesized to enhance the ECL performance. Due to the strong catalytic ability of CeO2, the ECL signal strength of the new material PCN-222@CeO2@Ag NPs is much higher than that of the PCN-222@Ag NPs and PCN-222. The luminous properties of PCN-222@CeO2@Ag NPs become more intense and stable due to the excellent electronic conductivity of Ag NPs. Based on the fact that CuS@PDA composite can quench the ECL signal of PCN-222@CeO2@Ag NPs, we constructed a novel sandwich ECL immune sensor for the detection of phosphorylated Tau 181 (p-Tau-181) protein. The ECL sensor has a great linear relationship with p-Tau-181 protein concentration, ranging from 1 pg/mL to 100 ng/mL. The detection limit is as low as 0.147 pg/mL. This work provides new ideas for developing sensitive ECL sensors for the p-Tau-181 protein, the marker of Alzheimer's disease.

A ZnIn2S4@ReS2/AgInS2-based photoelectrochemical aptasensor for the ultrasensitive detection of kanamycin

An ultrasensitive photoelectrochemical (PEC) aptasensor was originally designed by using ZnIn2S4/ReS2 as a photoactive material and AgInS2 as a signal amplifier. The signal amplifier AgInS2 was incubated on the terminal of H-DNA (immobilized on the ZnIn2S4/ReS2/FTO surface), leading to an enhanced photocurrent response. Then, due to the introduction of DNA2, the formation of a double-stranded structure caused AgInS2 to keep away from the electrode surface, and the photocurrent was reduced. In the presence of kanamycin, DNA2 was released from the system due to the competition relationship, and a restored photocurrent response was obtained. The combination of ZnIn2S4/ReS2 and AgInS2 accelerated the electron transfer and enhanced the separation efficiency of photogenerated electron-hole pairs, resulting in an improved performance of the PEC aptasensor, which was capable of accurate and sensitive detection of kanamycin in actual samples.

[The correlation between nutritional status, body composition, and symptoms in Parkinson's disease patients]

Objective: To investigate the relationship between nutritional status, body composition and symptoms of Parkinson's disease (PD). Methods: The study was conducted among 102 PD patients between November 2020 to April 2021 in the outpatient and inpatient of Neurology department of the Second Affiliated Hospital of Suzhou University. Basic data, such as age, gender, course of disease and Hoehn-Yahr (H-Y) stage of the patients, were collected. In the "open" state, the Unified Parkinson's Disease Rating Scale (UPDRS) and other scales were used to evaluate the clinical symptoms of PD patients. The nutritional status of PD patients was evaluated by the micro-nutrition rating Scale (MNA), and the body composition data of PD patients was measured by the body composition analyzer.The patients were divided into three groups according to the MNA: well-nourished group(45 cases), malnutrition-risk group (43 cases)and malnutrition group(14 cases). Body composition, laboratory tests, bone density, and symptoms of PD were compared among the three groups. Results: Among 102 PD patients, 48 were males (47.1%) and 54 were females (52.9%), aged 42-86 (66±9) years old. Compared with the malnutrition-risk group, lymphocytes in the malnutrition group [(1.45±0.48) × 109/L vs (1.76±0.43)×109/L], uric acid [(227±54) μmol/L vs (282±63) μmol/L] were all low, and the difference was statistically significant (all P<0.05). Compared with the well-nourished group, hemoglobin [(125±17) g/L vs (136±14) g/L], prealbumin [(0.23±0.05) g/L vs (0.27±0.06) g/L], and uric acid [(227±54) μmol/L vs (312±76) μmol/L] and Retinol binding protein [(33±7) mg/L were lower than (39±10) mg/L] in the malnutrition group, the difference was statistically significant (P<0.05). Except for the visceral fat area and body fat percentages, there was no significant difference in body composition indexes and bone mineral density T-value between the malnutrition-risk and malnutrition groups (P<0.05). Compared with the well-nourished group, the body fat [(16±6) kg vs (20±6) kg], the percentage of body fat [(26±9)% vs (29±7)%], the waist-hip ratio [(0.86±0.05) vs (0.89±0.05)], and the upper arm circumference [(29.00±2.59) cm vs (30.74±2.75) cm] in the malnutrition risk group were lower, and the difference was statistically significant (P<0.05). There were statistically significant differences in all body composition indicators and T-values of bone density between the malnourished and well nourished groups (all P<0.05). The MNA score of PD patients was negatively correlated with UPDRS Ⅰ, UPDRS Ⅱ, and UPDRS Ⅳ scores (r=-0.347, -0.364, -0.303, all P<0.05); Body composition indicators: total body water and inorganic salts were negatively correlated with UPDRS-I (r=-0.206, -0.223, all P<0.05), and body fat was negatively correlated with levodopa Equivalent dose (LED) (r=-0.209, P<0.05) Conclusions: The malnutrition risk and incidence of malnutrition in PD patients are high; lymphocyte, uric acid, hemoglobin, Retinol binding protein, body composition and bone mineral density were low in malnutrition group. MNA score of PD patients was negatively correlated with Parkinson's disease symptoms.

An electrochemiluminescence aptasensor based on highly luminescent silver-based MOF and biotin-streptavidin system for mercury ion detection

In this study, for the first time, a silver-based metal-organic framework (Ag-MOF) was synthesized and used as the electrochemiluminescence (ECL) emitter for building an ECL sensor. After modification with chitosan (CS) and gold nanoparticles (Au NPs), the ECL stability of Ag-MOF was improved. To detect mercury ions, a biosensor was constructed using the mercury ion aptamer and steric effect of streptavidin. First, the capture strand (cDNA) with terminal-modified sulfhydryl group was attached to the electrode surface by the Au-S bond. Then, the mercury-ion aptamer (Apt-Hg) modified with biotin was anchored to the electrode by complementary pairing with cDNA. Streptavidin (SA) could be fixed on the electrode by linking with biotin, thereby reducing the ECL signal. However, in the presence of mercury ions, the aptamer was removed and streptavidin could not be immobilized on the electrode. Hence, the ECL signal of the sensor increased with the concentration of mercury ions, which was linear in the range from 1 μM to 300 fM. The detection limit could reach 66 fM (S/N = 3). The sensor provided a new method for the detection of mercury ions.

A photoelectrochemical biosensor based on b-TiO2/CdS:Eu/Ti3C2 heterojunction for the ultrasensitive detection of miRNA-21

A novel photoelectrochemical (PEC) biosensor based on b-TiO₂/CdS:Eu/Ti₃C₂ heterojunction was developed for ultrasensitive determination of miRNA-21. In this device, the b-TiO₂/CdS:Eu/Ti₃C₂ heterojunction with excellent energy level arrangement effectively facilitated photoelectric conversion efficiency and accelerated the separation of the photogenerated electron hole pairs, which because that the structure of heterojunction overcomes the drawbacks of single material, such as narrow light absorption range, wide band gap, short carrier lifetime, etc., improves light utilization, extends the lifetime of photogenerated electron hole pairs, and promotes electron transfer. Herein, hairpin DNA1 (H1) decorated on the b-TiO₂/CdS:Eu/Ti₃C₂ electrode surface by Cd-S bonds, after H2/miRNA-21 heterduplex was introduced, the strand-displacement reaction (SDR) was triggered between H1 and H2/miRNA-21, accordingly, miRNA-21 was discharged from the H2/miRNA-21 heterduplex, forming the H1/H2 duplex, and the reuse of miRNA-21 was realized. As a signal amplification factor, the signal amplification factor H3-CdSe was hybridized with H1/H2 duplex, which greatly enhanced the sensitivity of the PEC biosensor. Under optimal conditions, the designed PEC biosensor displayed outstanding sensitivity, selectivity and stability with a wide liner range from 1.0 μM to 10.0 fM and a low detection limit of 3.3 fM. The preparation of the optoelectronic material affords a new direction for the progress of heterojunction photovoltaic materials and the construction of the proposed biosensor also provides a new thought for the PEC detection of human miRNA-21 with superior performance. Simultaneously, the established biosensor exhibiting tremendous possibility for detecting other biomarkers and biomolecules in clinical diagnosis fields.

Construction of FeNi-Mo2C@SiO2 monolith electrocatalyst with increased active sites and enhanced intrinsic activity toward water oxidation

The exploration of high-efficiency and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) remains a tremendous challenge. Herein, ultrafine FeNi-Mo2C composite immobilized on the surface of SiO2 support are fabricated...

Coupled electrochemiluminescent and resonance energy transfer determination of microRNA-141 using functionalized Mxene composite

The electrochemiluminescence and resonance energy transfer (ECL-RET) method was adopted to detect miRNAs, in which the two-dimensional Ti₃C₂ Mxenes with high surface area modified with CdS:W nanocrystals (CdS:W NCs) were used as ECL signal emitter. Mxenes with a specific surface area of 5.2755 m²/g carried more emitters and promote ECL intensity. As an energy acceptor, BiOCl nanosheets (BiOCl NSs) have a wide UV-Vis absorption peak in the range 250 nm-700 nm, including the emission band of CdS:W NCs with 520 nm emission wavelength. Hence, BiOCl NSs are covalently bound to hairpin DNA 2 by amide bond to quench the ECL signal of CdS:W NCs. In the presence of miRNA-141, the hairpin DNA 1 modified on the GCE was unfold and then paired with hairpin DNA 2 to release miRNA-141 and quench the signal of the ECL biosensor. Then, the concentration signal of miRNA-141 was amplified by catalytic hairpin assembly. The novel specific biosensor demonstrated a satisfactory linear relationship with miRNA-141 in the range 0.6 pM to 4000 pM; the detection limit was as low as 0.26 pM (3 s/m) under the potential of 0 ~ -1.3 V and showed outstanding RSD of 1.19%. The findings of the present work with high accuracy and sensitivity will be of positive significance for the clinical diagnosis of miRNA in the future work. The construction process of the biosensor and electrochemiluminescence mechanism.

[Study on the effect of AIDS preventive cascade services provided by social organizations for men who have sex with men in China]

Objective: To analyze the effect and main gaps of each stage in the AIDS prevention cascade for men who have sex with men (MSM) provided in intervention projects supported by the China AIDS Fund for non-governmental organizations (CAFNGO) and provide suggestions to improve the quality of cascade services and project management. Methods: Data were collected through the CAFNGO management information system and field interviews to analyze the differences in the number of MSM receiving HIV testing and confirming tests, the newly reported patients, and the number of antiviral treatment (ART) referrals of newly established reported patients among different social organization service areas. A service chain chart was also drawn. Results: Between 2016 and 2020, 1 508 MSM intervention projects were funded by CAFNGO, including 1 183 234 MSM being mobilized to receive HIV testing. However, only 68.8% (1 183 234/1 719 139) of the testing capacity of social organizations was covered by these projects. As a result, 55 783 HIV-positive MSM were detected in preliminary screening, and only 86.6% (48 327/55 783) received confirming tests. The proportion of newly reported infections was 3.8% (45 347/1 183 234). The ratio of antiviral treatment (ART) referrals for newly reported patients between 2017 and 2020 was 89.8% (32 719/36 444). 75.8%(1 143/1 508) of total MSM intervention projects were implemented by community-based organizations (Non-registered civil affairs departments). In comparison, organizations registered in civil affairs departments took up 24.2% (365/1 508) of the total MSM intervention projects. No significant difference was noticed in the proportion of newly reported infected (3.8% and 3.8%) and the ratio of ART referrals (89.7% and 89.9%) between community-based organizations and registered organizations' projects. But these two proportions are significantly different between these two types of organizations in some areas in China. Conclusions: The AIDS prevention cascade established in CAFNGO has effectively promoted the early detection and treatment of infected MSM. However, CAFNGO needs more financial support to extend testing coverage for MSM. Meanwhile, confirmation testing for positives in preliminary screening and ART referrals needs to be improved for newly reported patients. In addition, various capacity building needs to be provided for different social organizations.

ORAOV 1 Detection Made with Metal Organic Frameworks Based on Ti3C2Tx MXene

In this work, a two-dimensional (2D) MOF sheet with electrochemiluminescence (ECL) activity is prepared with Ti3C2Tx MXene as the metal precursor and the meso-tetra(4-carboxyl-phenyl) porphyrin (H2TCPP) as the organic ligand. The atomically thin 2D Ti3C2Tx MXene is utilized as the metal precursor and soft template to produce the MOF with a 2D nanosheet morphology (Ti3C2Tx-PMOF). Ti3C2Tx MXene is a kind of strong electron acceptor, which can deprotonate H2TCPP due to the high electronegativity and low work function of its terminal atoms. The deprotonated H2TCPP continues to bind with Ti atoms to form the 2D MOF sheet. The ECL activity is inherited from H2TCPP and stabilized by introducing Ag NPs. Then, we construct an ECL biosensor based on the Ag NPs/Ti3C2Tx-PMOF to detect the oral cancer overexpressed 1 (ORAOV 1). A bipedal three-dimensional DNA walker strategy is adopted to further improve the biosensor sensitivity. As expected, the biosensor exhibits sterling sensitivity and selectivity. The ECL biosensor responds linearly to ORAOV 1 concentrations in the range of 10 fM-1 nM, and the detection limit is as low as 3.3 fM (S/N = 3). It means that Ag NPs/Ti3C2Tx-PMOF is a potential material to design and construct the high-performance ECL biosensors.

An Iron(III)-Based Metal-Organic Gel-Catalyzed Dual Electrochemiluminescence System for Cytosensing and In Situ Evaluation of the VEGF165 Subtype

The recent surge of interest in metal-organic gels (MOGs) has emerged for their soft porous structure, large surface area, and abundant active metal sites, making them a promising candidate for building catalyst matrices. In this work, facilely synthesized Fe(III)-organic gel was directly used as a robust electrode matrix. Detailed studies illustrated that their Fe(III) centers can speed up the electro-oxidation/reduction of the H₂O₂ coreactant to produce reactive oxygen species for enhancing a potential-resolved dual electrochemiluminescence (ECL) emission. Among them, the anodic signal of luminol varied with the cell concentration based on the impedance ECL mechanism, while the cathodic signal of CdS quantum dots traced the VEGF₁₆₅ subtype at cell surface by specific aptamer recognition. Based on this, a ratiometric strategy was proposed for accurate cytosensing by eliminating environmental interference. Moreover, by cooperating these two signals, a novel strategy was developed for direct evaluation of the VEGF₁₆₅ subtype, further realizing rapid drug screening and subtype assessment on different cell lines. This work not only opens up the promising application of MOGs as an effective catalyst matrix but also develops reliable cell assays and protein subtype identification for clinical diagnosis and research.

Functionalized MOF PCN-222-loaded quantum dots as an electrochemiluminescence sensing platform for the sensitive detection of p-nitrophenol

The composite PCN-222@CdSe was used to detect PNP.

[Relationship between emotional apathy and motor symptoms, sleep and cognitive function in patients with early Parkinson's disease]

Objective: To study the relationship between emotional apathy and motor symptoms, sleep, and cognitive function in patients with early Parkinson's disease (PD). Methods: One hundred and twenty-nine early PD patients who were treated in the Second Affiliated Hospital of Soochow University from June to October 2020 were included, including 82 male and 47 female patients. The emotional apathy was assessed by modified apathy rating scale (MAES). The above 129 patients were divided into 67 patients in the PD with emotional apathy group (MAES>14 points) and 62 patients in the PD without emotional apathy group (MAES≤ 14 points). Age, gender, course of disease and levodopa equivalent dose were also collected. Hoehn-Yahr stage and unified Parkinson's disease rating scale PartⅢ(UPDRS-Ⅲ), Pittsburgh Sleep Quality Index (PSQI), polysomnography, and Montreal Cognitive Assessment Scale (MoCA) were used to evaluate the motor symptoms, sleep and cognitive functions of patients with early PD, and the clinical characteristics of patients with early PD with apathywere determined. Results: Compared with PD patients without apathy, those with apathy had longer disease duration [M(Q₁,Q₃)][5.0 (3.0, 7.0) years vs 3.0 (2.0, 5.0) years, P=0.006] and severer motor symptoms [20.0 (10.0, 28.0) vs 14.0 (8.5, 23.0), P=0.047]. There was no significant difference in PSQI score between the two groups. Among the 33 patients who completed polysomnography, compared with PD patients without apathy (n=16), those with apathy (n=17) had a longer rapid eye movement (REM) sleep latency [150 (124, 184) min vs 87 (57, 133) min, P=0.035)] and more frequent periodic limb movements in the REM phase(P=0.042).The REM sleep ratio (r=0.373, P=0.042), apnea-hypopena index (AHI)(r=0.374, P=0.046) and oxygen deficit index (r=0.409, P=0.025) were positively correlated with the degree of apathy in PD patients. PD patients with apathy had relatively poorer performance in cognition assessment than those without apathy and total MoCA score was inversely correlated with the degree of apathy (r=-0.231, P=0.017). Conclusion: Early PD patients with apathy have objective sleep disorders dominated by REM sleep disorders, which can have a negative impact on cognitive function.

[Transcranial sonographic characteristics of Parkinson's disease with symptoms of restless legs syndrome]

Objective: To evaluate the transcranial sonographic characteristics in patients with Parkinson's disease (PD) with symptoms of restless legs syndrome (RLS). Methods: Patients with diagnosis of definite PD from the Second Affiliated Hospital of Soochow University and 3 other participating hospitals between September 2018 and December 2019 were consecutively enrolled. Concurrent RLS symptoms were determined using Non-motor Symptoms Questionnaire. Transcranial sonography (TCS) and clinical assessments were performed during the same time and the related variables were compared between the two groups using t-test, non-parametric test, Chi-square test and Spearman correlation analysis, respectively. Results: Among 349 patients with PD, the prevalence of RLS symptoms was 22.6%. Compared to patients without RLS symptoms, those with RLS had longer disease duration (43.0 (24.0, 91.0) months vs 37.0 (20.0, 60.0) months, P<0.05) and higher Hoehn-Yahr stage (2.5 (2.0, 3.0) vs 2.0 (1.5, 2.5), P<0.01).TCS revealed that patients with RLS symptoms were more likely to have abnormality in the raphe nucleus (21.50% vs 7.78%, χ²=15.9, P<0.001) and increased third ventricle width ((6.22±1.97) mm vs (5.16±1.90) mm, P<0.001). No significant differences were found regarding parameters of substantia nigra. Conclusions: Concurrent RLS symptoms are common in PD patients. Abnormal echogenicity of raphe nucleus and increased third ventricle width could be characteristics of TCS in PD patients with RLS symptoms.

A label-free photoelectrochemical immunosensor for carcinoembryonic antigen detection based on a g-C3N4/CdSe nanocomposite

Herein, a label-free photoelectrochemical immunosensor based on a g-C3N4/CdSe nanocomposite was established and applied to detect carcinoembryonic antigen (CEA). The prepared nanocomposite materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectrometer (FT-IR) and photoluminescence spectroscopy (PL). The results indicate that g-C3N4/CdSe nanocomposite materials were successfully synthesized. In a typical assembly process, the immunosensor was constructed by modifying a fluorine-doped tin oxide (FTO) electrode with poly dimethyl diallyl ammonium chloride (PDDA), the g-C3N4/CdSe nanocomposite, the anti-carcinoembryonic antigen antibody (Ab) and the blocking agent bovine serum albumin (BSA) successively. In the presence of CEA, the photocurrent signal of the prepared immunosensor decreased significantly. Accordingly, under the optimal conditions, a label-free photoelectrochemical immunosensor was established, and it exhibited excellent selectivity and repeatability for CEA detection. The detection limit was 0.21 ng mL-1, and the range was 10 ng mL-1-100 μg mL-1. Simultaneously, the immunosensor also provides a likely sensing device for detecting other protein targets, which is of great significance for early clinical diagnosis.

[Effects of sleep quality and mood of patients with Parkinson's disease on their caregivers]

Objectve: To evaluate the relationship of Parkinson's disease(PD) patients' sleep quality and depression with burden, quality of life, and depression of their caregivers. Methods: A total of 120 PD patients (68 males and 52 females) and their caregivers (48 males and 72 females) from Changshu Hospital Affiliated to Nanjing University of Chinese Medicine between January 2017 and June 2019 were recruited. Patients' sleep quality, depression and quality of life was evaluated. Burden, quality of life, quality of sleep, and depression of caregivers were assessed by the Caregivers Burden Questionnaire (CBI), Health Survey Brief (SF-36), Pittsburgh Sleep Quality Index (PQS1) and Hamilton Depression Scale (HAMD), meanwhile, the correlation between relevant factors was analyzed. Results: The CBI of caregivers was positively correlated with the unified Parkinson's disease rating scale (UPDRS)-Ⅲ scores of PD patients (r=0.436, P<0.05). The CBI, SF-36GH, SF-36MH, HAMD and PSQI scores of caregivers were positively correlated with Parkinson's disease sleep scale (PDSS) scores of PD patients (r=0.546, 0.762, 0.528, 0.562 and 0.522, respectively, all P<0.01). The caregiver's CBI score was positively correlated with PD patients' Epworth sleepiness score (ESS) score (r=0.442, P<0.05), and caregiver's CBI, SF-36GH, SF-36MH, HAMD, PSQI scores were positively correlated with PD patients' HAMD scores (r=0.765, 0.813, 0.635, 0.884 and 0.601, respectively, all P<0.01). The caregiver's CBI score was positively correlated with the PDQ-39 score of PD patients (r=0.834, 0.452, 0.463, 0.421 and 0.387, respectively, all P<0.05). Multiple regression analysis indicated that the caregiver's CBI score was significantly correlated with the patient's PDQ-39, PDSS and HAMD scores (r=0.512, 0.645 and 0.635, respectively, all P<0.01), and the caregiver's SF-36GH score was significantly correlated with the patient's PDQ-39, PDSS and HAMD scores (r=0.452, 0.682 and 0.506, respectively, all P<0.01). The caregiver's SF-36MH score was significantly correlated with the patient's PDQ-39, PDSS and HAMD scores (r=0.426, 0.608 and 0.598, respectively, all P<0.01). There was significant correlations between the caregiver's HAMD score and the patient's PDSS and HAMD scores (r=0.568 and 0.496, both P<0.01), and the PSQI score of the caregiver was significantly correlated with the PDSS and HAMD scores of the patient (r=0.532 and 0.461, both P<0.01). Conclusions: This current study underscores the presence of a significant relationship of patient's sleep quality with caregiver's burden, quality of life, depression and sleep quality. Specifically, sleep quality and depression of the patients are independent predictors for burden, quality of life and sleep quality of the caregivers.

An electrochemiluminescence biosensor for p53 antibody based on Zn-MOF/GO nanocomposite and Ag+-DNA amplification

An ultrasensitive electrochemiluminescence biosensor was established based on the Zn-MOF/GO nanocomposite. Ag(I)-embedded DNA complexes were used as a signal amplification reagent. In this work, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and Zn²⁺ were integrated into a porphyrin paddlewheel framework (Zn-MOF) by a hydrothermal method. The synthesized Zn-MOF material has electrochemiluminescence property, and the luminescence intensity is improved after being composited with graphene oxide (GO). Based on the composite material, we constructed an ultrasensitive ECL biosensor for the p53 antibody detection. The composite material acted as an admirable substrate and then loaded plenty of p53 antigens to recognize the target (p53 antibody) accurately. Because of the bridging effect of streptavidin and biotin-conjugated goat anti-rabbit IgG (bio-ab2), the rich-C DNA with positive correlation with the target was modified on the electrode and then captured the co-reactant accelerator Ag⁺ to amplify the signal. Therefore, the ECL biosensor response increases with increasing p53 antibody concentration. In the range 0.1 fg/mL-0.01 ng/mL, the response signal of the biosensor has a good linear relationship with the p53 antibody concentration. The detection limit is 0.03 fg/mL (S/N = 3). Impressively, the biosensor not only featured high sensitivity, good stability, and excellent specificity for the detection of p53 antibody, but also provides a new way for early detection of cancer. Graphical abstract Schematic representation of the electrochemiluminescence sensor based on a Zn-MOF/GO nanocomposite, which can be applied to the determination of p53 antibody.

A silver nanoparticle-assisted signal amplification electrochemiluminescence biosensor for highly sensitive detection of mucin 1

A novel electrochemiluminescence (ECL) biosensor was developed in this study, which was based on the Ag-NP modified tetrahedral DNA nanostructure.

Synthesis of novel C-doped g-C3N4 nanosheets coupled with CdIn2S4 for enhanced photocatalytic hydrogen evolution

Photocatalytic hydrogen generation from water splitting has become a favorable route for the utilization of solar energy. An effective strategy, the combination of C-doping with nanocomposite semiconductors, is presented in this work. C-doped g-C₃N₄ (CCN) was prepared by supramolecular self-assembly and subsequently a number of CdIn₂S₄/CCN composite photocatalysts were designed and fabricated though in situ decoration of CdIn₂S₄ crystals on the surface of CCN nanosheets via a hydrothermal method. This unique architecture was able to efficiently promote the transfer and separation of photon-generated charges, enhance light absorption, and significantly increase photocatalytic H₂ production. Detailed characterization was performed to analyze the crystal structure, morphology, elementary composition, optical properties and catalytic mechanism. The CdIn₂S₄/CCN nanocomposites with optimal CdIn₂S₄ content exhibited a maximum H₂ production rate of 2985 μmol h^-1 g^-1, almost 15 times more than that obtained using pure g-C₃N₄ (205 μmol h^-1 g^-1). In addition, the hybrid photocatalysts display good recycling stability under visible-light irradiation. This research may provide promising information for the preparation of more efficient multifunctional hybrid photocatalysts with excellent stability in fine chemical engineering.

Synthesis of ultrathin WSe2 nanosheets and their high-performance catalysis for conversion of amines to imines

Tungsten diselenide (WSe2) is the material with the lowest thermal conductivity in the world. Most physical methods are used for the synthesis of tungsten diselenide. Here, a simple colloidal method is reported for the synthesis of WSe2 nanosheets. The composition, valence, size, morphology and properties of the samples were characterized and measured. Results showed that the obtained WSe2 nanosheets with a thickness of 0.7 nm had strong blue fluorescence. Significantly, the synthesized WSe2 nanosheets exhibited excellent catalytic activity for the aerobic coupling of amines to imines, with 100% yield under visible light irradiation and air atmosphere. As a photocatalyst, it exhibited excellent recyclability, and maintained a high yield after 5 cycles. It was found that this reaction could also happen in the presence of natural light by slightly extending the reaction time. Moreover, H2O was used as a solvent in the catalytic process, avoiding expensive and toxic organic solvents. This work provides an efficient, economical and sustainable process for the synthesis of imines and shows the great potential of WSe2 nanosheets as photocatalysts for organic synthesis.

Colloidal Synthesis and Thermoelectric Properties of CuFeSe₂ Nanocrystals

Copper-based chalcogenides that contain abundant, low-cost and environmentally-friendly elements, are excellent materials for numerous energy conversion applications, such as photocatalysis, photovoltaics, photoelectricity and thermoelectrics (TE). Here, we present a high-yield and upscalable colloidal synthesis route for the production of monodisperse ternary I-III-VI₂ chalcogenides nanocrystals (NCs), particularly stannite CuFeSe₂, with uniform shape and narrow size distributions by using selenium powder as the anion precursor and CuCl₂·2H₂O and FeCl₃ as the cationic precursors. The composition, the state of valence, size and morphology of the CuFeSe₂ materials were examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), respectively. Furthermore, the TE properties characterization of these dense nanomaterials compacted from monodisperse CuFeSe₂ NCs by hot press at 623 K were preliminarily studied after ligand removal by means of hydrazine and hexane solution. The TE performances of the sintered CuFeSe₂ pellets were characterized in the temperature range from room temperature to 653 K. Finally, the dimensionless TE figure of merit (ZT) of this Earth-abundant and intrinsic p-type CuFeSe₂ NCs is significantly increased to 0.22 at 653 K in this work, which is demonstrated to show a promising TE materialand makes it a possible p-type candidate for medium-temperature TE applications.

[Effect of obstructive sleep apnea on sleep architecture of acute ischemic stroke patients]

Objective: To investigate the effect of obstructive sleep apnea (OSA) on sleep architecture in acute ischemic stroke (AIS) patients. Methods: Seventy AIS patients with polysomnography examination from June 2014 to April 2016 were included in the Second Affiliated Hospital of Soochow University. Twenty-seven healthy controls during the same period were chosen as control group. According to apnea-hypopnea index (AHI), AIS patients were divided into AIS group (AHI<5/h) and AIS+ OSA group (AHI≥5/h). Their general conditions, Neurological function defect (national institutes of health stroke scale, NIHSS) on admission and at discharge and self-care ability (modified Rankin Scale, mRS) at discharge and 3 months later (mRS score <2 reflected good prognosis, and mRS score≥2 reflected unfavorable prognosis) were collected. Results: Fifty-two patients (74.3%) had OSA in total seventy AIS patients. Total sleep time (TST) was significantly shorter and sleep efficiency (SE) was lower in AIS group than the control group (P=0.007, 0.008, respectively). AIS+ OSA group had longer non-rapid eye movement (NREM)1 than control group [24.9(21.3) vs 14.3(10.6), P=0.044]. Compared with AIS group, AIS+ OSA group had shorter NREM3 [13.0(13.2) vs 19.6(12.8), P=0.039]. There was no significant difference between the infarct location of AIS group and AIS+ OSA group. However, AIS+ OSA group had higher mRS score observed at 3 months through follow-up visit than AIS group (P=0.027). Spearman correlation analysis showed a positive correlation between unfavorable prognosis of stroke at 3 months and atrial fibrillation, the oxygen desaturation index (ODI), percentage of oxygen saturation <90% of total recording time (TS90%), AHI, the longest time of apnea and hypopnea, respiratory related microarousal and NIHSS, while a negative correlation between unfavorable prognosis of stroke and NREM3, lowest nocturnal oxygen saturation (L-SaO(2)). On Logistic analysis, the unfavorable prognosis was independently predicted by AHI and NIHSS. Conclusions: Sleep architecture of cerebral infarction patients are disturbed with its characteristic of shorter total sleep time and lower sleep efficiency. Cerebral infarction patients with OSA have longer NREM1 and shorter NREM3.

Synthesis of TiO₂-loaded Co0.85Se thin films with heterostructure and their enhanced catalytic activity for p-nitrophenol reduction and hydrazine hydrate decomposition

P-nitrophenol (4-NP) and hydrazine hydrate are considered to be highly toxic pollutants in wastewater, and it is of great importance to remove them. Herein, TiO2-loaded Co0.85Se thin films with heterostructure were successfully synthesized by a hydrothermal route. The as-synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy and selective-area electron diffraction. The results demonstrate that TiO2 nanoparticles with a size of about 10 nm are easily loaded on the surface of graphene-like Co0.85Se nanofilms, and the NH3 · H2O plays an important role in the generation and crystallization of TiO2 nanoparticles. Brunauer-Emmett-Teller measurement shows that the obtained nanocomposites have a larger specific surface area (199.3 m(2) g(-1)) than that of Co0.85Se nanofilms (55.17 m(2) g(-1)) and TiO2 nanoparticles (19.49 m(2) g(-1)). The catalytic tests indicate Co0.85Se-TiO2 nanofilms have the highest activity for 4-NP reduction and hydrazine hydrate decomposition within 10 min and 8 min, respectively, compared with the corresponding precursor Co0.85Se nanofilms and TiO2 nanoparticles. The enhanced catalytic performance can be attributed to the larger specific surface area and higher rate of interfacial charge transfer in the heterojunction than that of the single components. In addition, recycling tests show that the as-synthesized sample presents stable conversion efficiency for 4-NP reduction.

Highly Sensitive Electrochemical Dopamine Sensor from Poly(diallyldimethylammonium chloride)-Functionalized Graphene Nanoribbon/Gold Nanoparticle Nanocomposite

A novel graphene oxide nanoribbon/poly(diallyldimethylammonium chloride)/gold nanoparticle (GONR/PDDA/AuNP) nanocomposite was synthesized successfully and used for the sensitive detection of dopamine. The GONR/PDDA/AuNP nanocomposite was characterized by transmission and scanning electron microscopy. The electrochemical sensor based on GONR/PDDA/AuNP nanocomposite. was studied by cyclic voltammetry and electrochemical impedance spectroscopy. Experimental parameters such as GONR/PDDA concentration, volume ratio of GONR/PDDA to AuNP, scan rates, and pH were studied to investigate their effect on peak currents. Under optimal conditions, the GONR/PDDA/AuNP-based sensor exhibited excellent electrocatalytic activity for the detection of dopamine with a wide linear range from 9.99 x 10(-8) to 8.69 x 10(-4) M and a low detection limit of 3.33 x 10(-8) M. Moreover, the proposed sensor exhibits high sensitivity, good reproducibility, and stability, and could therefore potentially be applied in other bioanalytical systems.

[Measurement and comparison of Zn, Fe, Cu, Mn, Cr, Pb and Cd in rabbit liver of high-adipose group and normal group]

The objective of the present paper is to explore the experimental changes in the content of Zn, Fe, Cu, Mn, Cr, Pb and Cd in white rabbit liver with atherosclerosis disease. The method is to reproduce white rabbit liver with atherosclerosis disease by a high-fat diet, and then measure the Zn, Fe, Cu, Mn, Cr, Pb and Cd content with atomic absorption spectrometry. Results show that the Zn, Fe, Cu, Mn, Cr, Pb and Cd contents in the fodders of the normal group are 137.6, 362.3, 14.39, 9.599 mg x kg(-1) and 159.3, 355.0, 290.0 microg x kg(-1), and 86.09, 277.1, 11.07, 5.366 mg x kg(-1) and 115.2, 286.0, 210.5 microg x kg(-1), in high-adipose group. It was concluded that Zn, Fe, Cu, Mn, Cr, Pb and Cd contents in white rabbit liver decline, which may have something to do with the intake of foods and the abnormalities of lipoprotein metabolism.

Direct electrochemistry and electrocatalytic behavior of hemoglobin entrapped in Ag@C nanocables/gold nanoparticles nanocomposites film

Direct electrochemistry of hemoglobin (Hb) was successfully fabricated by immobilizing Hb on the nanocomposites containing of Ag@C nanocables and Au nanoparticles (AuNPs) modified glassy carbon electrode (GCE). The immobilized Hb retained its biological activity and shown high catalytic activities to the reduction of H2O2 by circular dicroism (CD) spectrum, fourier transform infrared (FT-IR) spectrum and cyclic voltammetry (CV). Experimental conditions such as scan rate and pH Value were studied and optimized. The results indicated that the resulting biosensor are linear to the concentrations of H2O2 in the ranges of 6.67 x 10(-7)-2.40 x 10(5) M, and the detection limit is 2.02 x 10(-7) M. The electrochemical biosensor has also high stability and good reproducibility.

Sonochemical fabrication of 8-hydroxyquinoline aluminum (Alq3) nanoflowers with high electrogenerated chemiluminescence

Well-defined Alq(3) nanoflowers were fabricated via a facile and fast sonochemical route. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and shape of the as-prepared product. The results showed that the resulting Alq(3) was composed of nanobelts with thickness about 50 nm, average widths of 200 nm, and length up to 10 μm. The Alq(3) nanoflowers exhibited good electrogenerated chemiluminescence behavior.

Shape-controlled synthesis of PbCrO4 micro/nanostructures and their luminescent properties

PbCrO4 with different morphologies have been synthesized via a facile sonochemical route from an aqueous solution of lead acetate and potassium dichromate in the presence of nitrilotriacetate acid (H3NTA). The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The pH and the concentration of complexing reagent were found to have close relation with morphology of the final product. The possible growth mechanism of PbCrO4 microcube has been proposed. UV-Vis spectra and room-temperature photoluminescence of the PbCrO4 micro/nanostructures have also been investigated. Results showed that all the samples possessed strong photoluminescence (PL) properties, suggesting that the micro/nanostructures could be used in novel optoelectronic devices.

Sonochemical route for self-assembled V2O5 bundles with spindle-like morphology and their novel application in serum albumin sensing

Novel self-assembled V2O5 bundles with highly ordered superstructures and spindle-like morphology were synthesized by a rapid high-yielding sonochemical method. The as-prepared samples were characterized by X-ray diffraction, a field-emission scanning electron microscope, and a transmission electron microscope. The spindle-like V2O5 bundles are composed of several tens of homogeneous nanowires with diameters of 30-50 nm and lengths of 3-7 microm. A sensitive resonance light scattering method for the detection of bovine serum albumin (BSA) based on the self-assembled V2O5 bundles was developed. The results of the polarized resonance light scattering demonstrated that the Cabannes factor for the V2O5 bundles-BSA aggregates was BSA concentration-dependent.

Highly Luminescent Zinc(II)−Bis(8-hydroxyquinoline) Complex Nanorods: Sonochemical Synthesis, Characterizations, and Protein Sensing

Highly luminescent zinc(II)-bis(8-hydroxyquinoline) (Znq(2)) complex nanorods have been synthesized via a sonochemical route from the microemulsion containing zinc acetate and 8-hydroxyquinoline. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that the products were rod-like morphology with a diameter of about 200-450 nm and a length of about 1-3 microm. A possible mechanism for the formation of Znq(2) nanorods is proposed that the ultrasound wave might urge the collision and fusion of initial Znq(2) nuclei to form nanorods. The photoluminescence (PL) and resonance light scattering (RLS) of the products were also investigated. The Znq(2) nanorods were found to be sensitive to several proteins, such as human serum albumin (HSA), bovine serum albumin (BSA), bovine hemoglobin (Hb), and egg albumin (EA), displaying an increase in intensities of both PL and RLS. The protein-concentration dependence of the PL and RLS intensities can be well described as a Langmuir-type binding isotherm. This is the first report on the enhancement of PL and RLS intensities of Znq(2) nanorods by proteins. On the basis of enhanced PL and RLS intensities, the protein could be detected at the nanogram per milliliter level. The experimental results clearly showed that the Znq(2) nanorods were good protein probes for easy and highly sensitive detection.