The pulse light mode enhances the effect of photobiomodulation on B16F10 melanoma cells through autophagy pathway.

Photobiomodulation (PBM) is the use of low irradiance light of specific wavelengths to generate physiological changes and therapeutic effects. However, there are few studies on the effects of PBM of different LED light modes on cells. Here, we investigated the difference of influence between continuous wave (CW) and pulse-PBM on B16F10 melanoma cells. Our results suggested that the pulse mode had a more significant PBM than the CW mode on B16F10 melanoma cells. Our study confirmed that ROS and Ca2+ levels in B16F10 melanoma cells treated with pulse-PBM were significantly higher than those in the control and CW-PBM groups. One mechanism that causes the difference in CW and pulse-PBM action is that pulse-PBM activates autophagy of melanoma cells through the ROS/OPN3/Ca2+ signaling pathway, and excessive autophagy activation inhibits proliferation and apoptosis of melanoma cells. Autophagy may be one of the reasons for the difference between pulse- and CW-PBM on melanoma cells. More importantly, melanoma cells responded to brief PBM pulses by increasing intracellular Ca2+ levels.

Novel Porphyrin Zr Metal-Organic Framework (PCN-224)-Based Ultrastable Electrochemiluminescence System for PEDV Sensing.

The sensitive detection of coronavirus is of vital importance for the prevention of its rapid spread. Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that causes severe diarrhea and death in neonatal piglets. In this work, a novel PCN-224-based electrochemiluminescence (ECL) system was constructed for PEDV detection with high sensitivity. We found that PCN-224 can be employed as an ECL reporter with a strong signal because of its zirconium-based organic porous frame nanomaterial with a large specific surface area and stable structure. TiO2 nanoparticles were used as an accelerator for the first time to promote the reduction of coreactant potassium peroxydisulfate on the cathode; thus, the initial ECL signal of PCN-224 was significantly amplified. In the presence of PEDV, the ECL signal decreased due to the block effect to electron transfer. As a result, the novel "signal off" biosensor achieved a sensitive detection of PEDV ranging from 1 pg/mL to 10 ng/mL, with a detection limit of 0.4 pg/mL (S/N = 3). Importantly, the PCN-224 nanomaterial enriched the ECL system in biological analysis, and the proposed strategy provided a new route for coronavirus detection.

MiR-129-5p/DLX1 signalling axis mediates functions of prostate cancer during malignant progression.

We mainly corroborated the potential mechanism of DLX1 and miR-129-5p in prostate cancer cells. DLX1 was upregulated in cancer cells according to qRT-PCR assay. We evaluated the functional changes of the transfected cells via Transwell assay, CCK-8 assay and wound healing assay. DLX1 was confirmed as a cancer promoter. In addition, qRT-PCR showed down-regulated miR-129-5p expression in prostate cancer. We further used dual-luciferase reporter detection to elucidate the targeting between these two genes. The inhibition of miR-129-5p on tumour was verified. Besides, co-transfection of oe-DLX1 and miR-129-5p mimics attenuated this inhibition. These data demonstrated functions of DLX1/miR-129-5p axis in prostate cancer: miR-129-5p hindered the biological functions of cancer cells via inhibiting DLX1 expression. We provide a novel biomarker for prostate cancer.

Programmable DNA Tweezer-Actuated SERS Probe for the Sensitive Detection of AFB1.

A DNA tweezer is a dynamic DNA nanomachine that can reversibly switch its state between open and closed. Here, we employed a DNA tweezer for the first time to dynamically control the distance between plasmonic silver nanoparticles (Ag NPs) for a surface enhanced Raman scattering (SERS) biosensing application. Two DNA and 4-nitrothiophenol (4-NTP) modified Ag NPs were linked to the arms of the DNA tweezer (DNA tweezer-Ag NPs probe) by complementary base pairing. Activation of the Raman intensity was achieved by the state transformation of the DNA tweezer-Ag NPs probe from open to closed. The distances between two Ag NPs in open and closed state were 8.1 ± 2.7 nm and 3.2 ± 0.8 nm, respectively. Furthermore, the two Ag NPs were spatially separated in the open state with a low Raman signal, whereas in the closed state, Raman intensity was enhanced because of the proximity of two Ag NPs. The developed biosensing system exhibited a good linear relationship when the concentration of aflatoxin B1 (AFB1) ranged from 1 ng/mL to 0.01 pg/mL, and the limit of detection (LOD) was 5.07 fg/mL. In addition, spike recovery and certificated real foodstuffs were used to examine the feasibility in a real situation. This protocol provides a potential candidate for SERS detection and can be used as a promising technology for biological and chemical sensors.

Pomegranate-Inspired Silica Nanotags Enable Sensitive Dual-Modal Detection of Rabies Virus Nucleoprotein.

The outbreak of rabies virus (RABV) in Asia and Africa has attracted widespread concern due to its 100% mortality rate, and RABV detection is crucial to its diagnosis and treatment. Herein, we report a sensitive and reliable strategy for the dual-modal RABV detection using pomegranate-shaped dendritic silica nanospheres fabricated with densely incorporated quantum dots (QDs) and horseradish peroxidase (HRP)-labeled antibody. The immunoassay involves the specific interaction between virus and nanospheres-conjugated antibody coupled with robust fluorescence signal originating from QDs and naked-eye discernible colorimetric signal on the oxTMB. The ultrahigh loading capacity of QDs enables the detection limit down to 8 pg/mL via fluorescence modality, a 348-fold improvement as compared with conventional enzyme-linked immunosorbent assay (ELISA). In addition, the detection range was from 1.20 × 102 to 2.34 × 104 pg/mL by plotting the absorbance at 652 nm with RABV concentrations with a detection limit of 91 pg/mL, which is nearly 2 order of magnitude lower than that of the conventional ELISA. Validated with 12 brain tissue samples, our immunoassay results are completely consistent with polymerase chain reaction (PCR) results. Compared with the PCR assay, our approach requires no complex sample pretreatments or expensive instruments. This is the first report on RABV diagnosis using nanomaterials for colorimetry-based prescreening and fluorescence-based quantitative detection, which may pave the way for virus-related disease diagnosis and clinical analysis.

Kanamycin Adsorption on Gold Nanoparticles Dominates Its Label-Free Colorimetric Sensing with Its Aptamer.

A short kanamycin-binding aptamer has been widely used for detecting kanamycin. One of the popular signaling methods is based on the color change of gold nanoparticles (AuNPs) to develop label-free colorimetric biosensors. The general perception was that aptamer binding to its target would inhibit aptamer adsorption by the AuNPs. This inhibited adsorption results in the aggregation of the AuNPs and a color change upon addition of salt. However, the potential adsorption of kanamycin was ignored. Herein, we carefully studied the adsorption of kanamycin on AuNPs and performed a comprehensive analysis using two mutated aptamers and a randomly sequenced DNA which were not supposed to bind kanamycin. In addition, a total of six antibiotics were studied over a wide concentration range. As low as 90 nM kanamycin can induce the aggregation of 3 nM citrate-capped AuNPs, indicating very strong adsorption of kanamycin. The color change was independent of DNA sequence, and all the tested sequences showed a similar color response, regardless of aptamer. Among the different antibiotics, kanamycin and streptomycin induced a color change but not the other four. Our results support an alternative mechanism that kanamycin and streptomycin adsorption by the AuNPs was the main reason for the color change instead of aptamer binding.

Synthesis, biological evaluation and anti-proliferative mechanism of fluorine-containing proguanil derivatives.

Proguanil, a member of biguanide family, has excellent anti-proliferative activities. Fluorine-containing compounds have been demonstrated to have super biological activities including enhanced binding interactions, metabolic stability, and reduced toxicity. In this study, based on the intermediate derivatization methods, we synthesized 13 new fluorine-containing proguanil derivatives, and found that 7a,7d and 8e had much lower IC50 than proguanil in 5 human cancerous cell lines. The results of clonogenic and scratch wound healing assays revealed that the inhibitory effects of derivatives 7a,7d and 8e on proliferation and migration of human cancer cell lines were much better than proguanil as well. Mechanistic study based on representative derivative 7a indicated that this compound up-regulates AMPK signal pathway and downregulates mTOR/4EBP1/p70S6K. In conclusion, these new fluorine-containing derivatives show potential for the development of cancer chemotherapeutic drugs.

Cauliflower-Inspired 3D SERS Substrate for Multiple Mycotoxins Detection.

Surface-enhanced Raman spectroscopy (SERS) is a promising analytical tool, but simultaneous detection of multiple targets using SERS remains a challenge. Herein, a cauliflower-inspired 3D SERS substrate with intense hot spots was prepared through sputtering Au nanoparticles (Au NPs) on the surface of polydimethylsiloxane coated anodic aluminum oxide (PDMS@AAO) complex substrate. As a result, the cauliflower-inspired 3D SERS substrate achieved the highest SERS activities at a sputtering time of 8 min. Under the optimal conditions, this SERS substrate possessed a low detection limit of 10-12 M, excellent enhancement uniformity (relative standard deviation, RSD = 4.57%) and high enhancement factor (2.2 × 106) for 4-mercaptobenzoic acid (4-MBA). Furthermore, the results of Raman showed that the 3D-Nanocauliflower SERS substrates could realize the simultaneous label-free detection for three mycotoxins (aflatoxin B1, deoxynivalenol, and zearalenone) in maize for the first time. It behaved good linear relationship between the concentrations and Raman intensities of aflatoxin B1, zearalenone, and deoxynivalenol. For the three mycotoxins, this method exhibited the limit of detection (LOD) of 1.8, 47.7, and 24.8 ng/mL (S/N = 3), respectively. The 3D-Nanocauliflower SERS substrates with dense hot spots presented remarkable SERS effect and activity, which could be act as a potential candidate for SERS substrate applied in the rapid and label-free detection.

Catalytic hairpin assembly-assisted lateral flow assay for visual determination of microRNA-21 using gold nanoparticles.

The authors describe an improved lateral flow assay based on (a) the use of catalytic hairpin assembly (CHA), and (b) on signal amplification performed at the interface of gold nanoparticles (AuNPs). The combination of the amplification capability of the CHA reaction and the unique optical properties of AuNPs results in an assay that has a sensitivity that is improved by more than two orders of magnitude. MicroRNA-21 was employed as a model analyte to prove the concept. The presence of microRNA-21 triggers the self-assembly of two hairpin DNAs into double stranded DNA and exposing biotin molecules on the surface of AuNPs. Hence, the target becomes recycled and the signal is strongly amplified. The AuNPs carrying biotin are captured on the test line of the strip to display a red zone. This enables the visual recognition of microRNA without the need for any instrumentation. The fast quantitation of microRNA via the red band intensity is accomplished with the help of software, and the limit of detection is 0.89 pM. The enhanced lateral flow assay was employed to the determination of microRNA-21 in cell extracts and spiked serum samples. Graphical abstract A lateral flow assay for microRNA is described with a detection limit that is improved by two orders of magnitude. It is based on catalytic hairpin assembly (CHA) signal amplification performed at the interface of gold nanoparticles.

LEO-Augmented GNSS Based on Communication Navigation Integrated Signal.

Low Earth Orbit (LEO) is of great benefit for the positioning performance of Global Navigation Satellite System (GNSS). To realize the system of LEO-augmented GNSS, three methods to integrate communication and navigation signal for LEO communication system with the least influence on the communication performance are analyzed. The analysis adopts the parameters of IRIDIUM signal as restrictions. This paper gives quantitative comparison of these methods considering CN0(carrier noise power spectral density rate) margin, pseudorange accuracy, Doppler accuracy, and communication loss. For method 1, a low-power navigation signal is added to the communication signal. For method 2, the navigation signal is launched in one or more frames. For method 3, the navigation signal is launched in the frequency band separated to the communication signal. The result shows that the pseudorange accuracy of method 2 is far below method 1 and method 3. However, the difference of Doppler accuracy among the three methods can be emitted. Detailed analysis shows that method 1 is practicable when the communication and navigation signal power rate is 15 dB. It achieves the balance of pseudorange accuracy and bit error rate (BER) performance under this condition. Comprehensive comparison of these methods is given in the last. The result shows that the CN0 margin of the navigation signal for method 3 can be 13.04 dB higher than method 1, based on the accuracy threshold considered in this paper. Methods 1 and 3 have the advantage of high accuracy and high CN0 margin respectively. However, method 3 causes high communication capacity loss. Considering that the main disadvantage of GNSS signals is low CN0, method 3 is a good choice for the LEO-augmented GNSS system. Methods 1 and 3 can be combined to realize both high accuracy and high CN0 margin if possible.

High glucose stimulates proliferative capacity of liver cancer cells possibly via O-GlcNAcylation-dependent transcriptional regulation of GJC1.

Although it is generally accepted that diabetes is one of the most important risk factors for liver cancer, the underlying mechanism is still not well understood. The purpose of the current study is to further investigate how high concentrations of glucose (HG), a major symptom of diabetes, stimulate the development of liver malignancy. Using data mining, gap junction protein gamma 1 (GJC1) was identified as a critical proto-oncoprotein that is essential for the HG stimulation of proliferative capacity in liver cancer cells. Furthermore, enhanced transcriptional expression of GJC1 might occur after stimulation by HG. A transcription factor zinc finger protein 410 (APA1)-binding motif was found to be located at the -82 to -77 nt region within the GJC1 promoter. Without APA1, HG was unable to increase GJC1 expression. Interestingly, APA1, but not GJC1, can be O-GlcNAcylated in liver cancer cells. Moreover, O-GlcNAcylation is essential for HG-induced APA1 binding to the GJC1 promoter. Notably, global O-GlcNAcylation and expression of APA1 and GJC1 were highly elevated in liver cancer patients with diabetes compared to those in patients without diabetes. The HG-stimulated proliferative capacity was abolished upon decreasing O-GlcNAcylation, which could be reversed gradually by the simultaneous overexpression of APA1 and GJC1. Therefore, GJC1 could be a potential target for preventing liver cancer in patients with diabetes.

Versatile Electrochemiluminescence Assays for PEDV Antibody Based on Rolling Circle Amplification and Ru-DNA Nanotags.

The sensitive and accurate detection methods for PEDV antibody have practical significance for the prevention and treatment of PEDV. In this work, a new multiple pathways signal amplification method was proposed to construct a sensitive electrochemiluminescence (ECL) platform for the detection of PEDV antibody. Using Au NP-modified graphene nanosheet (Au-GN) as the substrate, antibody-antigen reaction as the recognition unit, rolling circle amplification (RCA) for signal enhancement, and assembled cascade Ru-DNA nanotags as signal label, the proposed platform behaved with good specificity and sensitivity. The binding system of biotin-streptavidin, RCA, and Ru(bpy)32+-doped silica nanoparticles (Ru SNPs) showed remarkable amplification efficiency, low background signal, and little nonspecific adsorption. Moreover, the proposed ECL sensor exhibited good analytical performance for PEDV antibody with a wide linear range from 0.1 pg mL-1 to 5000 pg mL-1 with a detection limit of 0.05 pg mL-1 ( S/ N = 3). The proposed strategy exhibited the advantages of excellent stability and sensitivity for determination of the PEDV antibody, which was easy to prepare and had a good application prospect.

AMOT is required for YAP function in high glucose induced liver malignancy.

AMOT has been identified as a YAP interactor. However, how AMOT regulates YAP remains unclear and controversy. Here, we identified that besides YAP, AMOT was another Hippo signaling core factor which could be O-GlcNAcylated. Moreover, high glucose (HG) was able to enhance the expression and O-GlcNAcylation of AMOT. We also found that HG stimulated nuclear accumulation, transcription activity, interaction with transcription factor and transcription of target genes of YAP via AMOT, while AMOT acted as a suppressor of YAP in normal glucose level. Finally, we observed the upregulation and nuclear accumulation of AMOT and YAP in Streptozocin (STZ) induced high glucose mice. Collectively, we have uncovered that AMOT acts as a YAP stimulator in high glucose level. Targeting the aberrantly regulated core factors in Hippo pathway might be a more effective therapeutic approach for liver cancer associated with possibly diabetes.

Differential expression of microRNAs in hemocytes from white shrimp Litopenaeus vannamei under copper stress.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate diverse cellular processes, including organismal stress response, through posttranscriptional repression of gene transcripts. They are known to have antiviral functions in aquatic crustacean species, but little is known about the role of miRNAs against environmental stress caused by Cu, a common chemical contaminant in aquatic environment. We performed small RNA sequencing to characterize the differentially expressed microRNAs in Cu exposed shrimp. A total of 4524 known miRNAs and 73 novel miRNAs were significantly (P < .05) differentially expressed after Cu exposure. The peak size of miRNAs was 22 nt. Among them, 218 miRNAs were conserved across 115 species. The validation of 12 miRNAs by stem-loop quantitative RT-PCR were found to be coherent with the expression profile of deep sequencing data as evaluated with Pearson's correlation coefficient (r = 0.707). Target genes of these differentially expressed miRNAs related to immune defense, apoptosis, and xenobiotics metabolism also showed significant changes in expression under Cu stress. The present study provides the first characterization of L. vannamei miRNAs and some target genes expression in response to Cu stress, and the findings support the hypothesis that certain miRNAs along with their target genes might be essential in the intricate adaptive response regulation networks. Our current study will provide valuable information to take an insight into molecular mechanism of L. vannamei against environmental stress.

Antitumor Activity of Diterpenoids from Jatropha gossypiifolia: Cell Cycle Arrest and Apoptosis-Inducing Activity in RKO Colon Cancer Cells.

Nine new minor diterpenoids, jatrogossones A-I (1-9), and six known analogues (10-15) were separated from an extract of the branches and leaves of Jatropha gosspiifolia. Compounds 4-6 and 10, possessing a 5/11 fused-ring skeleton, and 8, 9, and 13, with a 5/9/5 fused-ring skeleton, represent rare diterpenoid skeletons that have been found only in compounds isolated from plants of the Jatropha genus. The absolute configurations of 1-10 were defined by using a combination of electronic circular dichroism data analysis and single-crystal X-ray diffraction data. The cytotoxicity of the diterpenoids was evaluated using RKO and LOVO colon cancer cells in which regenerating islet-derived protein 3-alpha (Reg3A) is highly expressed. Compound 12 exhibited cytotoxicity against RKO colon cancer cells with an IC50 value of 2.6 µM. Morphological features of apoptosis and antimigration activities were evaluated in 12-treated RKO cells. Compound 12 effectively induced apoptosis of RKO, which was associated with G2/M-phase cell cycle arrest. Flow cytometric analysis showed that the treatment by 12 significantly induced RKO cell apoptosis in a dose-dependent manner.

Placental expression of AChE, α7nAChR and NF-κB in patients with preeclampsia.

OBJECTIVES: This study aimed to investigate placental expression of AChE, α7nAChR and NF-κB in patients with preeclampsia and discuss about its clinical significance. MATERIAL AND METHODS: mRNA expression levels of acetylcholine (AChE), alpha-7 nicotinic acetylcholine receptor (α7nAChR) and nuclear factor-kB (NF-κB) in placenta were detected by qRT-PCR, and protein levels were determined by immunohis-tological analysis and Western Blot in 35 women with preeclampsia (including 20 cases of mild preeclampsia and 15 cases of severe preeclampsia) and 30 cases in control group, respectively. RESULTS: The expression of AChE mRNA and protein in placenta increased significantly in patients with preeclampsia compared with the control group (p < 0.01). It was lower in patients with severe preeclampsia than in patients with mild preeclampsia (p < 0.05). The expression of α7nAChR mRNA and protein in placenta decreased significantly in patients with preeclampsia compared with the control group (p < 0.01). However, the expression of α7nAChR mRNA and protein in patients with severe preeclampsia was higher than that in patients with mild preeclampsia, without significant difference(p > 0.05). The expression of NF-κB protein in placenta decreased significantly in patients with preeclampsia compared with the control group(p < 0.01). It was higher in patients with severe preeclampsia than in patients with mild preeclampsia (p < 0.05), but there was no significant difference between preeclampsia group and control group in the expression of NF-κB mRNA in placenta (p > 0.05). The results of Western blotting assay were consistent with those of immunohistochemistry. CONCLUSIONS: Abnormal expression of AChE, α7nAChR and NF-κB in placenta may be associated with preeclampsia. Cho-linergic anti-inflammatory pathway may play an important role in the pathogenesis of preeclampsia.

Gecko-Inspired Nanotentacle Surface-Enhanced Raman Spectroscopy Substrate for Sampling and Reliable Detection of Pesticide Residues in Fruits and Vegetables.

Rapid sampling and multicomponent detection are crucial for monitoring of pesticide residues analysis. Here, a gecko-inspired nanotentacle surface-enhanced Raman spectroscopy (G-SERS) platform is proposed for the first time for the simultaneous detection of three kinds of pesticides via a simple and intuitive "press and peeled-off" approach. The G-SERS platform obtained from seeding deposition of silver nanoparticles (Ag NPs) on 3D PDMS nanotentacle array is flexible and free-standing. Compared with other substrates, this G-SERS substrate can simultaneously provide outstanding SERS activity (enhancement factor = 1.2 × 107), superior reproducibility (RSD = 5.8%) and countless flexible nanoscale "tentacles" (∼6.7 × 108/cm2). Moreover, the high density of "tentacles" can freely approach the microarea and enable efficient target collection, which were confirmed by SEM and HPLC. By direct sampling from cucumber, apple, and grape surfaces, thiram (TMTD), methyl parathion (MPT), malachite green (MG), and their multiple components have been rapidly and reliably determined. For example, under the optimal conditions, a sensitivity of 1.6 ng/cm2 (S/N = 3) for TMTD was obtained on apple peels with a correlation coefficient (R) of 0.99. Therefore, the G-SERS substrate could offer a great practical potential for on-spot identification of various pesticide residues on real samples.

Signal-Amplified Near-Infrared Ratiometric Electrochemiluminescence Aptasensor Based on Multiple Quenching and Enhancement Effect of Graphene/Gold Nanorods/G-Quadruplex.

Dual-signaling ratiometric electrochemiluminescence (ECL) technology has attracted particular attention in analytical science due to its precise measurement to normalize variation in environmental changes. Creating new mated ECL report units with two emitting states and improving the detection sensitivity are major challenges for ratiometric ECL measurement. Here, we fabricate an ultrasensitive near-infrared ratiometric ECL aptasensor based on a dual-potential signal amplification strategy triggered by the quencher/enhancer [graphene/hemin/gold nanorods/G-quadruplex-hemin (rGO-H-AuNRs-G4H) composite]. The composite was initially prepared through three consecutive steps: the π-π stacking interaction between hemin and graphene, in-site growth of AuNRs, and surface ligand exchange. Dual ECL quenching of quantum dots (QDs) and multiple signal enhancement of luminol can be achieved simultaneously by the fabrication of the sandwich "thrombin aptamer I (TBA1)-TB-TBA2 (rGO-H-AuNRs-G4H)" mode: (i) the formation of three-dimensional G-quadruplex between aptamer and thrombin not only shortens the distance between the donor (QDs) and receptor (rGO-H and AuNRs) to trigger electrochemiluminescence energy transfer but also provides the place for intercalating hemin; (ii) the hemin intercalated into G4 structure and hemin connected onto rGO together with AuNRs/rGO nanomaterials can achieve the multiple peroxidase-like catalysis of H2O2 to greatly enhance the ECL of luminol. The ratiometric ECL aptasensor self-calibrated by the internal reference (luminol or QDs) exhibits ultrasensitive and accurate analytical performance toward thrombin (TB) with a linear detection range from 100 ng/mL to 0.5 pg/mL and a detection limit of 4.2 fg/mL [defined as signal-to-noise ratio (S/N) = 3].

Carbon-Dot and Quantum-Dot-Coated Dual-Emission Core-Satellite Silica Nanoparticles for Ratiometric Intracellular Cu(2+) Imaging.

Copper (Cu(2+)) is physiologically essential, but excessive Cu(2+) may cause potential risk to plants and animals due to the bioaccumulative properties. Hence, sensitive recognition is crucial to avoid overintake of Cu(2+), and visual recognition is more favored for practical application. In this work, a dual-emission ratiometric fluorescent nanoprobe was developed possessing the required intensity ratio, which can facilitate the sensitive identification of Cu(2+) by the naked eye. The probe hybridizes two fluorescence nanodots (quantum dots (QDs) and carbon dots (CDs)). Although both of them can be viable fluorescence probes for metal ion detection, rarely research has coupled this two different kinds of fluorescence material in one nanosensor to fabricate a selectively ratiometric fluorescence probe for intracellular imaging. The red emitting CdTe/CdS QDs were capped around the silica microsphere to serve as the response signal label, and the blue-emitting CDs, which is insensitive to the analyte, were covalently attached to the QDs surface to act as the reference signal. This core-satellite hybrid sphere not only improves the stability and brightness of QDs significantly but also decreases the cytotoxicity toward HeLa cells tremendously. Moreover, the Cu(2+) could quench the QDs emission effectively but have no ability for reduction of the CDs emission. Accordingly, a simple, efficient, and precise method for tracing Cu(2+) was proposed. The increase of Cu(2+) concentration in the series of 0-3 × 10(-6) M was in accordance with linearly decrease of the F650/F425 ratio. As for practical application, this nanosensor was utilized to the ratiometric fluorescence imaging of copper ions in HeLa cells.

Clean Synthesis of an Economical 3D Nanochain Network of PdCu Alloy with Enhanced Electrocatalytic Performance towards Ethanol Oxidation.

A one-pot method for the fast synthesis of a 3D nanochain network (NNC) of PdCu alloy without any surfactants is described. The composition of the as-prepared PdCu alloy catalysts can be precisely controlled by changing the precursor ratio of Pd to Cu. First, the Cu content changes the electronic structure of Pd in the 3D NNC of PdCu alloy. Second, the 3D network structure offers large open pores, high surface areas, and self-supported properties. Third, the surfactant-free strategy results in a relatively clean surface. These factors all contribute to better electrocatalytic activity and durability towards ethanol oxidation. Moreover, the use of copper in the alloy lowers the price of the catalyst by replacing the noble metal palladium with non-noble metal copper. The composition-optimized Pd80 Cu20 alloy in the 3D NNC catalyst shows an increased electrochemically active surface area (80.95 m(2) g(-1) ) and a 3.62-fold enhancement of mass activity (6.16 A mg(-1) ) over a commercial Pd/C catalyst.