A dual-response fluorescence sensor for SO derivatives and polarity and its application in real water and food samples.

As an important gaseous pollutant, SO derivatives generally exist and significantly threaten the environment and organism health. Meanwhile, polarity is a disease-related indicator in the organism's microenvironment, where an unregulated variation may disturb the physiological metabolisms. Hence, a superior FRET-based fluorescent sensor (TLA) is presented to track polarity and sulfur dioxide derivatives by dual emission channel, an elevated red emission at 633 nm with decreasing polarity as well as a reduced red emission at 633 nm and improved blue emission at 449 nm with increasing concentration of SO derivatives.

An ultrasensitive photoelectrochemical assay for tumor necrosis factor-alpha based on hollow CdS cubes as a signal generator and NiCoO-Au as a signal extinguisher.

Sensitive detection of tumor necrosis factor-alpha (TNF-α) in human serum is beneficial for finding cancer patients early due to overexpressed TNF-α being related to some cancers. Here, a photoelectrochemical (PEC) aptasensor was constructed for ultrasensitive TNF-α assay based on the signal generator of hollow CdS cubes (H-CdS) and the signal extinguishing activity of NiCoO-Au. In this work, compared with traditional solid CdS, H-CdS could greatly promote the PEC signal because its hollow structure could accelerate the separation of photogenerated charges, which also possesses abundant active sites and high light absorption capability.

Light-driven uranyl-organic frameworks used as signal-enhanced photoelectrochemical sensors for monitoring anthrax.

The semiconductor-like characteristics and light absorption ability of metal-organic frameworks (MOFs) make it have the potential for photoelectrochemical sensing. Compared with composite and modified materials, the specific recognition of harmful substances directly using MOFs with suitable structures can undoubtedly simplify the fabrication of sensors. Herein, two photosensitive uranyl-organic frameworks (UOFs) named HNU-70 and HNU-71 were synthesized and explored as the novel "turn-on" photoelectrochemical sensors, which can be directly applied to monitor the biomarker of anthrax (dipicolinic acid).

Colorimetric and Photocurrent-Polarity-Switching Photoelectrochemical Dual-Mode Sensing Platform for Highly Selective Detection of Mercury Ions Based on the Split G-Quadruplex-Hemin Complex.

Mercury ion (Hg) is one of the most harmful heavy metal ions with the greatest impact on public health. Herein, based on the excellent catalytic activity toward 3,3',5,5'-tetramethylbenzidine (TMB) and the strong photocurrent-polarity-switching ability to SnS photoanode of the split G-quadruplex-hemin complex, the magnetic NiCoO@SiO-NH sphere-assisted colorimetric and photoelectrochemical (PEC) dual-mode sensing platform was developed for the Hg assay. First, the amino-labelled single-stranded DNA1 (S1) was immobilized on NiCoO@SiO-NH and then partly hybridized with another single-stranded DNA2 (S2).

A label-free photoelectrochemical biosensor with ultra-low-background noise for lead ion assay based on the CuO-CuO-TiO heterojunction.

Herein, a label-free and ultra-low-background-noise PEC biosensor was developed for lead ion (Pb) assay based on the CuO-CuO-TiO heterojunction. By calcination of cupric ion (Cu) doped-titanium based metal organic framework (MOF) material (NH-MIL-125), the CuO-CuO-TiO heterojunction was synthesized. With Pb, lots of DNA single strands (S1) could be released based on the Pb assisted cyclic amplification strategy and hybridized with hairpin DNA (HP1) on the modified electrode.

Highly Selective Photoelectrochemical Assay of Arsenate Based on Magnetic CoO-FeO Cubes and the Negative-Background Signal Strategy.

Water pollution presents a significant environmental concern on earth. Herein, due to the serious environmental harmfulness of arsenate [As(V)], an iron phthalocyanine (FePc)-induced switchable photocurrent-polarity platform was developed for highly selective assay of As(V). First, magnetic CoO-FeO cubes were obtained by calcination of the CoFe Prussian blue analogue and then functionalized with oligonucleotide (S1).

Highly Selective and Sensitive microRNA-210 Assay Based on Dual-Signaling Electrochemical and Photocurrent-Polarity-Switching Strategies.

Highly sensitive and selective microRNA (miRNA) assay is of great significance for disease diagnosis and therapy. Herein, a magnetic-assisted electrochemistry (EC)-photoelectrochemistry (PEC) dual-mode biosensing platform was developed for miRNA-210 detection based on dual-signaling EC and photocurrent-polarity-switching PEC strategies. Porous magnetic FeO octahedra with a large surface area were synthesized by calcining Fe-based metal-organic frameworks.

A photocurrent-polarity-switching biosensor for highly selective assay of mucin 1 based on target-induced hemin transfer from ZrO hollow spheres to G-quadruplex nanowires.

Herein, a photocurrent polarity switching platform for highly selective assay of mucin 1 (MUC1) was developed based on target-induced hemin transfer from ZrO hollow spheres (ZrO HSs) to G-quadruplex nanowires (G wires). In this system, SiO spheres were used as templates to synthesize the uniform and mesoporous ZrO HSs. As nanocontainers, ZrO HSs could load hemin in its cavity via pores.

Sensitive Dual-Mode Biosensors for CYFRA21-1 Assay Based on the Dual-Signaling Electrochemical Ratiometric Strategy and "On-Off-On" PEC Method.

Herein, an electrochemical (EC)-photoelectrochemical (PEC) dual-mode biosensor was constructed for cytokeratin 19 fragment 21-1 (CYFRA21-1) assay based on the dual-signaling electrochemical ratiometric strategy and "on-off-on" PEC method. The indium tin oxide (ITO) electrode was modified by 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA)@C and gold nanoparticles (Au NPs), and the double-stranded DNA composed of thiol/methylene blue (MB)-labeled single-stranded DNA (ssDNA) (S0-MB) and antibody/ferrocene (Fc)-labeled ssDNA (Ab1-S1-Fc) was immobilized on the Au NPs/PTCDA@C/ITO electrode via the Au-S bond between Au NPs and thiol of S0-MB. With the help of another antibody-labeled ssDNA (Ab2-S2), the presence of CYFRA21-1 triggered a typical antigen-antibody sandwich immune reaction (Ab1, CYFRA21-1, and Ab2) and proximity hybridization between Ab1-S1-Fc and Ab2-S2.

Peptide Cleavage-Mediated and Environmentally Friendly Photocurrent Polarity Switching System for Prostate-Specific Antigen Assay.

As the most important serum biomarker for prostate cancer, sensitive and accurate detection of prostate-specific antigen (PSA) is of great reference value for the clinical diagnosis and treatment of prostate cancer. Herein, a peptide cleavage-mediated and environmentally friendly photocurrent polarity switching system was developed for ultrasensitive and highly selective detection of PSA based on the efficiently switching of photocurrent polarity of silver indium sulfide nanoparticles (AgInS NPs)-coated indium tin oxide (ITO) electrode by amino-functionalized CuO cubes (NH-CuO). The porous CuO cubes were synthesized by calcination of HKUST-1 and functionalized with aminosilane.

Label-free and near-zero-background-noise photoelectrochemical assay of methyltransferase activity based on a BiS/TiC Schottky junction.

Herein, a novel label-free photoelectrochemical (PEC) sensing platform with near-zero background noise was developed for M.SssI CpG methyltransferase (M.SssI MTase) activity assay based on a new Schottky junction of BiS/TiC nanosheets.

CuO-ZnO heterojunction derived from Cu-doped ZIF-8: A new photoelectric material for ultrasensitive PEC immunoassay of CA125 with near-zero background noise.

By direct calcination of Cu-doped ZIF-8 in oxygen atmosphere, a new photoelectric material, CuO-ZnO heterojunction, was prepared. The morphology and structure were investigated in detail by several methods, such as scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption method and X-ray diffraction. Under visible light irradiation, CuO-ZnO heterojunction exhibits excellent PEC behavior in aqueous media with the presence of ascorbic acid (AA) and dissolved oxygen at -0.

Highly Selective and Sensitive Photoelectrochemical Sensing Platform for VEGF165 Assay Based on the Switching of Photocurrent Polarity of CdS QDs by Porous CuO-CuO Flower.

Herein, a highly selective and sensitive photoelectrochemical (PEC) sensing platform was developed for vascular endothelial growth factor 165 (VEGF165) assay based on the porous CuO-CuO flower-induced photocurrent-polarity switching of the CdS quantum dots (QDs) modified indium-tin oxide (ITO) electrode. The porous CuO-CuO flower with uniform size and large surface area was successfully synthesized by taking Cu-MOF (HKUST-1) as the precursor. Through VEGF165-triggered catalytic hairpin assembly process, the porous CuO-CuO flower was introduced to the surface of the CdS QDs/ITO electrode, resulting in the switching of the photocurrent polarity from anodic current to cathodic current.

Graphene blended with SnO and Pd-Pt nanocages for sensitive non-enzymatic electrochemical detection of HO released from living cells.

This paper described a novel, facile and nonenzymatic electrochemical biosensor to detect hydrogen peroxide (HO). The sensor was fabricated based on Pd-Pt nanocages and SnO/graphene nanosheets modified electrode (PdPt NCs@SGN/GCE). The electrochemical behavior of PdPt NCs@SGN/GCE exhibited excellent catalytic activity toward HO with fast response, high selectivity, superior sensitivity, low detection limit of 0.

Facile synthesized SnO decorated functionalized graphene modified electrode for sensitive determination of daidzein.

A one-step and facile method using SnCl·HO as reducing agent to reduce graphene oxide (GO) was performed in the aid of poly(diallyldimethylammonium chloride) solution (PDDA). SnCl·HO is not only a reducing agent for graphene oxide (GO), but also a precursor of SnO. SnO-PDDA-GR composite was characterized by various surface, structural and electrochemical analysis techniques, such as transmission electron microscopy (TEM), UV spectrum (UV-vis), Infrared Spectrum (IR), X-ray diffraction (XRD), Cyclic voltammograms (CV) and electrochemical impedance (EIS).

Sensitive, simultaneous determination of chrysin and baicalein based on TaO-chitosan composite modified carbon paste electrode.

Chrysin and baicalein are the major flavonoids found in oroxylum indicum, an essential herb in traditional Chinese medicine (TCM). Owing to their similar characteristics and physiochemical property, it is a great challenge to detect both of them simultaneously. In this work, tantalum oxide (TaO) particles and chitosan modified carbon paste electrode (TaO-CTS-CPE) was prepared and characterized by scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectrum(EIS).

Autophagy induction by tetrahydrobiopterin deficiency.

Tetrahydrobiopterin (BH₄) deficiency is a genetic disorder associated with a variety of metabolic syndromes such as phenylketonuria (PKU). In this article, the signaling pathway by which BH₄ deficiency inactivates mTORC1 leading to the activation of the autophagic pathway was studied utilizing BH₄-deficient Spr(-/-) mice generated by the knockout of the gene encoding sepiapterin reductase (SR) catalyzing BH₄ synthesis. We found that mTORC1 signaling was inactivated and autophagic pathway was activated in tissues from Spr(-/-) mice.

Differential effects of specific amino acid restriction on glucose metabolism, reduction/oxidation status and mitochondrial damage in DU145 and PC3 prostate cancer cells.

Selective amino acid restriction targets mitochondria to induce apoptosis of DU145 and PC3 prostate cancer cells. Biochemical assays and flow cytometry were uitilized to analyze the glucose consumption, lactate production, pyruvate dehydrogenase (PDH), nicotinamide adenine dinucleotide (NAD)/NADH and nicotinamide adenine dinucleotide phosphate (NADP)/NADPH ratios, mitochondrial glutathione peroxidase (GPx), manganese superoxide dismutase (SOD), glutathione, reactive oxygen species (ROS) and DNA damage in DU145 and PC prostate cancer cells cultured under various amino acid deprived conditions. Restriction of tyrosine and phenylalanine (Tyr/Phe), glutamine (Gln) or methionine (Met) differentially modulated glucose metabolism and PDH and antioxidant enzyme activity in the mitochondria of the two prostate cancer cell lines.

Cell death of prostate cancer cells by specific amino acid restriction depends on alterations of glucose metabolism.

Selective amino acid restriction targets mitochondria resulting in DU145 and PC3 prostate cancer cell death. This study shows that restriction of tyrosine and phenylalanine (Tyr/Phe), glutamine (Gln), or methionine (Met) differentially modulates glucose metabolism, glycogen synthase kinase 3beta (GSK3beta), p53, and pyruvate dehydrogenase (PDH) in these two cell lines. In DU145 cells, Gln and Met restriction increase glucose consumption, but Tyr/Phe restriction does not.

Selective amino acid restriction differentially affects the motility and directionality of DU145 and PC3 prostate cancer cells.

We previously found that selective restriction of amino acids inhibits invasion of two androgen-independent human prostate cancer cell lines, DU145 and PC3. Here we show that the restriction of tyrosine (Tyr) and phenylalanine (Phe), methionine (Met) or glutamine (Gln) modulates the activity of G proteins and affects the balance between two actin-binding proteins, cofilin and profilin, in these two cell lines. Selective amino acid restriction differentially reduces G protein binding to GTP in DU145 cells.

Specific amino acid dependency regulates the cellular behavior of melanoma.

Relative specific amino acid dependency is one of the metabolic abnormalities of melanoma cells and metabolic studies of this dependency are in their infancy. Herein, we review the current studies in this area and present new information that adds to the understanding of how tyrosine (Tyr) and phenylalanine (Phe) dependency as well as other amino acids regulate the cell behaviors of melanoma cells. Amino acid dependency of human melanoma cells is multifactorial and restricting Tyr and Phe to melanoma triggers a series of alterations in metabolic and signaling pathways in a time-ordered fashion to alter different cellular behaviors.

Resveratrol is rapidly metabolized in athymic (nu/nu) mice and does not inhibit human melanoma xenograft tumor growth.

Resveratrol has been shown to have anticarcinogenic activity. We previously found that resveratrol inhibited growth and induced apoptosis in 2 human melanoma cell lines. In this study we determined whether resveratrol would inhibit human melanoma xenograft growth.

Selective amino acid restriction targets mitochondria to induce apoptosis of androgen-independent prostate cancer cells.

Relative specific amino acid dependency is one of the metabolic abnormalities of cancer cells, and restriction of specific amino acids induces apoptosis of prostate cancer cells. This study shows that restriction of tyrosine and phenylalanine (Tyr/Phe), glutamine (Gln), or methionine (Met), modulates Raf and Akt survival pathways and affects the function of mitochondria in DU145 and PC3, in vitro. These three restrictions inhibit energy production (ATP synthesis) and induce generation of reactive oxygen species (ROS).

Specific amino acid restriction inhibits attachment and spreading of human melanoma via modulation of the integrin/focal adhesion kinase pathway and actin cytoskeleton remodeling.

We had previously found that selective restriction of amino acids inhibits invasion of human A375 melanoma. Integrins, cell surface receptors for the components of extracellular matrix (ECM), are activated during cell adhesion and spreading, and initiate signaling pathways that control growth and invasion of tumor cells. We examined the effect of tyrosine (Tyr) and phenylalanine (Phe), methionine (Met) or glutamine (Gln) restriction on attachment and spreading of A375 and MeWo melanoma cell lines on fibronectin and laminin.

Daxx-mediated transcriptional repression of MMP1 gene is reversed by SPOP.

Daxx-mediated transcriptional repression was modulated by a speckled POZ domain protein SPOP which was first identified as an autoantigen from the serum of a scleroderma patient. This is the first report on the biochemical and functional interactions between Daxx and SPOP. The COOH-terminal region of Daxx interacts with the NH2-terminal region of SPOP.