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Loft Strand posted an update 2 months ago
05-10 nM, and the detection limit for miRNA-21 was 1 pM with excellent selectivity and reproducibility. Furthermore, this sensor successfully evaluated the expression level of miRNA-21 in clinical blood samples from healthy individuals and gastrointestinal cancer patients, and the results were highly consistent with those of qRT-PCR, suggesting the great clinical application value in the diagnosis of cancer associated with miRNA-21 expression levels. Development of a mitochondria-targeting fluorescent probe with large Stokes shift and long-wavelength emission was benefit for accurate detection of hypoxic status, which was known as a major factor of the tumor physiology and influence important pathological processes. However, an efficient optical approach for simultaneously achieving such merits was still lacking. In this work, a turn-on fluorescence probe (HBT-NP) was designed to assess the hypoxic condition of tumor cells by detecting nitroreductase (NTR). Probe HBT-NP was constructed by conjugating 4-nitrobenzyl moiety as reaction site for NTR to 2-(benzothiazol-2-yl)-4-methylphenol derived fluorescent dye HBT-Py which demonstrated large Stokes shift (Δλ = 243 nm) and long wavelength emission (λem = 640 nm) due to intrinsic mechanism of ESIPT together with ICT process. Upon incubated with NTR, HBT-NP could successively undergo nitro reduction reaction and then release HBT-Py. The reaction mechanism was further confirmed by mass spectra and HPLC analysis, and the docking calculation also indicated that the binding mode and docking affinity of probe HBT-NP with NTR play an important role in catalytic reduction reaction process. As a result, HBT-NP displayed a wide linear range (0.1-1.5 μg/mL) and low detection limit (2.8 ng/mL) response to NTR, and could be used to evaluate hypoxic condition of cancer cells with precise mitochondria-targeting. A new-fangled C3-symmetric triaminoguanidine-pyrrole conjugate has been constructed and utilized for sensing applications. selleckchem The probe selectively detects zinc ions (Zn2+) by colorimetric as well as turn-on fluorescent manner. Further, the in-situ formed zinc ensemble displays turn-off fluorescence response towards the pyrophosphate anion (PPi) via displacement approach. Emissive off-on-off sensing characteristics of the probe has been successfully exploited to construct the INHIBIT logic gate, coding/decoding of messages and in vivo imaging of Zn2+/PPi in zebrafish larvae. Further, PPi detection characteristics of zinc ensembles were established for the sensing of PPi discharged from DNA synthesis and other biological reactions. Possibilities of room temperature spectrometry based on Mn-doped ZnS quantum dots coated with a molecularly imprinted polymer based nanosensor have been explored for the sensitive and selective determination of aflatoxins. Synthesized polymeric nanoparticles exhibit intense room temperature phosphorescence (total decay time of 0.004 s) and aflatoxins quench the room temperature phosphorescence when interact with the recognition cavities of the molecularly imprinted polymer attached to the phosphorescent quantum dots. Room temperature phosphorescence was recorded by scanning from 520 nm to 720 nm (maximum peak intensity at 594 nm) after excitation at 290 nm. The prepared imprinted material was found to have higher adsorption capacity than those based non-imprinted quantum dots, demonstrating high adsorption uptake for aflatoxins. In addition, selectivity studies have demonstrated that the material offers a specific recognition for aflatoxins. Room temperature phosphorescence quenching by aflatoxins was found to be linear within the 2-20 μg L-1 range, and a limit of detection of 3.56 μg kg-1 was obtained. This value was lower than the maximum acceptable/residual level (aflatoxins in feeds) published by the European Commission. The results indicate a simple room temperature phosphorescence nanosensor for aflatoxins detection in fish feed as a versatile tool having excellent sensitivity and selectivity. Hypochlorite (ClO-) and hydrogen peroxide (H2O2) commonly coexist in organism and are involved in the same physiological and pathological processes. So it is of great importance to develop fluorescent probes to detect both simultaneously. Herein, we reported the first dual-site fluorescent probe (Geisha-1) for the quantitative detection of ClO- and H2O2. This probe is constructed by chemically grafting N,N-dimethylthiocarbamate and borate to a fluorescence resonance energy transfer (FRET) platform. As a result, Geisha-1 not only presents three different responses to ClO-, H2O2, and ClO- + H2O2 (the coexistence of ClO- and H2O2) with high sensitivity and selectivity, but also exhibits low toxicity and cell membrane and tissue permeability, and it was further successfully applied to image ClO- and H2O2 in living cells and tissues. Thus, Geisha-1 provides a promising application prospect in biological systems and an alternative strategy for the construction of dual-site fluorescent probes aiming at the multi-response detection of other biologically relevant analytes. Multiplex DNA methylation and glycosylation are ubiquitous in the human body to ensure the normal function and stability of the genome. The methyltransferases and glycosylases rely on varied enzymes with different action mechanism, which still remain challenges for multiple detection. Herein, we developed a tri-functional dsDNA probe mediated exponential amplification strategy for sensitive detection of human DNA (cytosine-5) methyltransferase 1 (Dnmt1) and uracil-DNA glycosylase (UDG) activities. The tri-functional dsDNA probe was rationally designed with M-DNA and U-DNA. M-DNA contains the 5′-GCmGCGC-3′ site for Dnmt1 recognition. U-DNA possesses one uracil as the substrate of UDG and a primer sequence for initiating the amplification reaction. M-DNA was complementary to partial sequence of U-DNA. In the presence of Dnmt1 and UDG, BssHⅡ and Endo Ⅳ were used to nick the 5′-GCGCGC-3′ and AP sites respectively, resulting in the release of single-stranded DNA sequence (primer sequence), respectively. After magnetic separation, the released primer sequence hybridizes with padlock DNA (P-DNA), initiating exponential rolling circle amplification to produce numerous G-quadruplexes for recordable signals.
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Start with a huge, uncovered box, or even a kiddie pool, and fill with a thick layer (about 6 inches) of unscented clay or fine sand-like particulate clumping/scoopable litter. For Ollie, you may need to play around with the substrate types to make it more natural. Try using soil or peat.