A novel ratiometric sensor for fluorimetric and visual dual-mode detection of Al in environmental water based on the target-regulated formation of Eu MOFs.

Herein, a novel ratiometric sensor for fluorimetric and smartphone-assisted visual detection of Al in environmental water was developed based on the target-regulated formation of Eu metal-organic frameworks (Eu MOFs). By employing 2-[4-(2-hydroxyethyl) piperazin-1-yl] ethanesulfonic acid (Hepes), Eu and tetracycline (TC) as raw materials, Eu MOFs with red emission were facilely synthesized through the coordination of Eu with Hepes and TC. However, upon the introduction of Al, a higher affinity of TC towards Al resulted in the formation of a TC-Al complex with green fluorescence and inhibited the generation of Eu MOFs.

A facile fluorescence Eu MOF sensor for ascorbic acid and ascorbate oxidase detection.

In this work, a facile fluorescence Eu-based metal-organic framework (Eu MOF) sensor for ascorbic acid (AA) and ascorbate oxidase (AAO) detection was developed. The fluorescence of the Eu MOF could be effectively quenched by Ce but not by Ce at an appropriate concentration, and thus, when the reductant AA was added into the solution containing Ce, Ce was chemically reduced to Ce, which induced the decreased fluorescence signal of the Eu MOF. However, when AAO was introduced, AA was effectively oxidized to dehydroascorbic acid (DHAA) under the catalysis of AAO, and thus, Ce could not be reduced, resulting in the fluorescence restoration of the Eu MOF.

A redox modulated fluorescence nanoplatform for the detection of alkaline phosphatase activity with fluorescent polydopamine nanoparticles.

Herein, we simply synthesized intrinsic fluorescent polydopamine nanoparticles (PDA NPs) in sodium hydroxide solution (NaOH, pH 11), and constructed a new fluorescence nanoplatform for the detection of alkaline phosphatase (ALP) using PDA NPs as an effective signal reporter. The nanoplatform was constructed by the combination of enzymatic hydrolysis of ALP to the substrate l-ascorbic acid-2-phosphate (AA2P) and the chemical redox reaction between l-ascorbic acid (AA) and mercury ion (Hg2+). The fluorescence of PDA NPs could be effectively quenched by Hg2+ through the coordination effect between Hg2+ and the functional groups on the surface of PDA NPs.

Fluorescent polydopamine nanoparticles as a nanosensor for the sequential detection of mercury ions and l-ascorbic acid based on a coordination effect and redox reaction.

Herein, a novel fluorescence nanosensor using intrinsic fluorescent polydopamine nanoparticles (PDA NPs) as an effective signal reporter has been constructed for the simple, rapid and sequential detection of mercury ions (Hg) and l-ascorbic acid (AA) based on a coordination effect and redox reaction. The fluorescence of the PDA NPs could be specifically quenched by Hg through intense coordination effects between the Hg and the groups (catechol, amine, ketone and imine) on the surface of the PDA NPs. However, when AA and Hg coexisted in solution, the fluorescence of the PDA NPs pronouncedly recovered the redox reaction of Hg, with it being reduced to Hg by AA.

MnO Nanosheet-based Fluorescence Sensing Platform for Sensitive Detection of Endonuclease.

A novel fluorescence sensing platform for ultrasensitive detection of S1 nuclease activity has been constructed based on MnO nanosheets and FAM labeled single-stranded DNA (FAM-ssDNA). In this system, MnO nanosheets were found to have different adsorbent ability toward ssDNA and mono- or oligonucleotide fragments. FAM-ssDNA could adsorb on MnO nanosheets and resulted in significant fluorescence quenching through fluorescence resonance energy transfer (FRET), while mono- or oligonucleotide fragments could not adsorb on MnO nanosheets and still retained strong fluorescence emission.

Reduction in greenhouse gas emissions from sludge biodrying instead of heat drying combined with mono-incineration in China.

Unlabelled: Sludge is an important source of greenhouse gas (GHG) emissions, both in the form of direct process emissions and as a result of indirect carbon-derived energy consumption during processing. In this study, the carbon budgets of two sludge disposal processes at two well-known sludge disposal sites in China (for biodrying and heat-drying pretreatments, both followed by mono-incineration) were quantified and compared. Total GHG emissions from heat drying combined with mono-incineration was 0.

MnO2-induced synthesis of fluorescent polydopamine nanoparticles for reduced glutathione sensing in human whole blood.

Polydopamine (PDA) nanoparticles, as a kind of popular polymer material, have attracted a great deal of attention from various areas including materials science, biomedicine, energy, environmental science and so on owing to their striking physicochemical properties. Herein, we reported for the first time the synthesis of intrinsic fluorescent PDA nanoparticles using MnO2 as an oxidant. In the presence of MnO2, dopamine was quickly oxidized into its quinone derivative, and autopolymerized into fluorescent PDA nanoparticles.

Endonuclease IV cleaves apurinic/apyrimidinic sites in single-stranded DNA and its application for biosensing.

Endonuclease IV (Endo IV), as a DNA repairing enzyme, plays a crucial role in repairing damaged DNA comprising abasic sites to maintain genomic integrity. The cleaving capability of Endo IV to apurinic/apyrimidinic sites (AP) in single-stranded DNA (ssDNA) was demonstrated. It was found that Endo IV has considerably high cleaving activity to AP sites in ssDNA compared with that in double-stranded DNA (dsDNA).

Fabrication of a LRET-based upconverting hybrid nanocomposite for turn-on sensing of H2O2 and glucose.

Blood glucose detecting has aroused considerable attention because diabetes mellitus has become a worldwide publish health problem. Herein, we construct an exceptionally simple upconverting hybrid nanocomposite, composed of DNA-templated Ag nanoparticles (DNA-AgNPs) and NaYF4:Yb/Tm@NaYF4 core-shell upconversion nanoparticles (UCNPs), for the sensing of H2O2 and glucose. In this design, UCNPs with bared surface act as the donor, and DNA-AgNPs serve as efficient quenchers.

"Light-up" Sensing of human 8-oxoguanine DNA glycosylase activity by target-induced autocatalytic DNAzyme-generated rolling circle amplification.

Human 8-oxoguanine DNA glycosylase (hOGG1) plays a crucial role in maintaining the genomic integrity of living organisms for its capability of repairing DNA oxidative damage. The expression level of hOGG1 is closely associated with many diseases including various kinds of cancers. In this study, a novel "light-up" sensor based on target-induced formation of 5' phosphorylated probe and autocatalytic DNAzyme-generated rolling circle amplification has been developed for highly sensitive human 8-oxoguanine DNA glycosylase (hOGG1) activity assay.

Phosphorylation-induced formation of a cytochrome c-peptide complex: a novel fluorescent sensing platform for protein kinase assay.

A novel fluorescent sensing platform has been developed for protein kinase assay based on the phosphorylation-induced formation of a cytochrome c-peptide complex.

A cobalt oxyhydroxide-modified upconversion nanosystem for sensitive fluorescence sensing of ascorbic acid in human plasma.

Ascorbic acid (AA), a potent antioxidant readily scavenging reactive species, is a crucial micronutrient involved in many biochemical processes. Here, we have developed a cobalt oxyhydroxide (CoOOH)-modified upconversion nanosystem for fluorescence sensing of AA activity in human plasma. The nanosystem consists of upconversion nanoparticles (UCNPs) NaYF4:30% Yb,0.

A G-quadruplex-based Label-free Fluorometric Aptasensor for Adenosine Triphosphate Detection.

A G-quadruplex-based, label-free fluorescence assay was demonstrated for the detection of adenosine triphosphate (ATP). A double-stranded DNA (dsDNA), hybridized by ATP-aptamer and its complementary sequence, was employed as a substrate for ATP binding. SYBR Green I (SG I) was a fluorescent probe and exonuclease III (Exo III) was a nuclease to digest the dsDNA.

MnO2-Nanosheet-Modified Upconversion Nanosystem for Sensitive Turn-On Fluorescence Detection of H2O2 and Glucose in Blood.

Blood glucose monitoring has attracted extensive attention because diabetes mellitus is a worldwide public health problem. Here, we reported an upconversion fluorescence detection method based on manganese dioxide (MnO2)-nanosheet-modified upconversion nanoparticles (UCNPs) for rapid, sensitive detection of glucose levels in human serum and whole blood. In this strategy, MnO2 nanosheets on the UCNP surface serve as a quencher.

A new label-free and turn-on strategy for endonuclease detection using a DNA-silver nanocluster probe.

Endonuclease plays a vital role in a variety of biological processes and the assay of endonuclease activity and inhibitors is of high importance in the fields ranging from biotechnology to pharmacology. Howerer, traditional techniques usually suffer from time intensive, laborious, and cost-expensive. This work aims to develop a facile and sensitive method for endonuclease activity assay by making use of the fluorescence enhancement effect when DNA-silver nanoclusters (DNA-Ag NCs) are in proximity to guanine-rich DNA sequences.

Phospholipid-modified upconversion nanoprobe for ratiometric fluorescence detection and imaging of phospholipase D in cell lysate and in living cells.

Phospholipase D (PLD) is a critical component of intracellular signal transduction and has been implicated in many important biological processes. It has been observed that there are abnormalities in PLD expression in many human cancers, and PLD is thus recognized as a potential diagnostic biomarker as well as a target for drug discovery. We report for the first time a phospholipid-modified nanoprobe for ratiometric upconversion fluorescence (UCF) sensing and bioimaging of PLD activity.

Efficiency influence of exogenous betaine on anaerobic sequencing batch biofilm reactor treating high salinity mustard tuber wastewater.

When treating a composite mustard tuber wastewater with high concentrations of salt (about 20 g Cl(-) L(-1)) and organics (about 8000 mg L(-1) COD) by an anaerobic sequencing batch biofilm reactor (ASBBR) in winter, both high salinity and low temperature will inhibit the activity of anaerobic microorganisms and lead to low treatment efficiency. To solve this problem, betaine was added to the influent to improve the activity of the anaerobic sludge, and an experimental study was carried to investigate the influence of betaine on treating high salinity mustard tuber wastewater by the ASBBR. The results show that, when using anaerobic acclimated sludge in the ASBBR, and controlling biofilm density at 50% and water temperature at 8-12 degrees C, the treatment efficiency of the reactor could be improved by adding the betaine at different concentrations.

Fractional, biodegradable and spectral characteristics of extracted and fractionated sludge extracellular polymeric substances.

Correlation between fractional, biodegradable and spectral characteristics of sludge extracellular polymeric substances (EPS) by different protocols has not been well established. This work extracted sludge EPS using alkaline extractants (NH₄OH and formaldehyde + NaOH) and physical protocols (ultrasonication, heating at 80 °C or cation exchange resin (CER)) and then fractionated the extracts using XAD-8/XAD-4 resins. The alkaline extractants yielded more sludge EPS than the physical protocols.