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In this work, we designed, simulated, and tested a complementary split ring resonator (CSRR) for the purpose of applying a strong and uniform microwave field for the manipulation of nitrogen vacancy (NV) ensembles. This structure was fabricated by etching two concentric rings on a flat metal film that was deposited on a printed circuit board. A metal transmission on the back plane was used as the feed line. The fluorescence collection efficiency was improved by about 2.5 times with the CSRR structure compared to that without CSRR. Furthermore, the maximum Rabi frequency could reach 11.3 MHz, and the Rabi frequency variation was smaller than 2.8% in an area of 250 × 75 μm. This could pave the way to achieving high-efficiency control of the quantum state for spin-based sensor applications. [ABSTRACT FROM AUTHOR]

A feasible double-site near-infrared (NIR) fluorescent probe Q5 based on xanthenes was developed. Probe Q5 showed clearly HSO3− induced changes in the fluorescence ratio of two well-separated NIR and VIS peaks, showing excellent selectivity compared with other analytes. And the detection limit of the probe for HSO3− was found to be 89 nM. Furthermore, fluorescence imaging experiments of HSO3− in CEM cells revealed that the probe has potential application value in biological systems. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A new ESIPT-based fluorescent probe for Hg2+ has been designed and developed. • The probe exhibits high sensitivity for mercury ions in aqueous solution. • The probe was successfully used for fluorescence imaging of Hg2+ in live cells. Abstract A new Excited-State Intramolecular Proton Transfer (ESIPT) based fluorescent probe for the detection of Hg2+ has been rationally designed and developed. Based on the specific reactivity of mercury-promoted hydrolysis, the probe exhibits high selectivity and sensitivity for mercury ions in almost pure aqueous solution (containing only 1% DMSO) with a low detection limit of 1.9 ppb. Furthermore, the probe was also successfully used for fluorescence imaging of Hg2+ in live cells. [ABSTRACT FROM AUTHOR]

Based on fluorescent resonance energy transfer (FRET), we developed a ratiometric fluorescent probe 1 for sensing Cu 2+ . As expected, probe 1 exhibited high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Cu 2+ in aqueous solution. A significant color change from pale yellow to pink could be observed, enabling naked-eye detection of Cu 2+ . Furthermore, fluorescence imaging experiment of Cu 2+ in living MGC-803 cells demonstrated its value of practical applications in biological systems. [ABSTRACT FROM AUTHOR]

A new probe (RosN3), which displayed excellent selectivity to H2S in mixed aqueous media, was synthesized. This method employed the H2S-mediated reduction of azides to amines, resulting in fluorescence quenching. The probe exhibited high H2S selectivity over other common anions and biothiols. The detection limit was measured to be 0.25 μM. Furthermore, the live cell imaging results demonstrated its potential for practical application in biological systems. [ABSTRACT FROM AUTHOR]

A bispyrene fluorescence probe with the cavitand linkage (compound 1) was synthesized, which was proved to be a versatile platform due to the ability of adopting two spatially well‐defined conformations: a closed vase and an expanded kite. vase‐1 was switched to kite‐1 upon addition of TFA or cooling, whereas kite‐1 was isomerized to vase‐1 in the presence of NEt3 or through heating. The interconversion in this molecular switch was tightly associated with the change of fluorescence as we found that changing the temperature and pH of the system‐ a bispyrene compound 1 and gelator 2 led to the sol ‐ gel transformation and reversible intramolecular excimer emission. Briefly, the results show that the fluorescence decreases in the gelation phase and is enhanced in the solution due to variations in temperature and pH. we thus concluded that 1 could be a useful fluorescence probe to determine the multiple states of organogel. [ABSTRACT FROM AUTHOR]

The demand for nucleic acid detection is increasing worldwide as people are impacted by infectious diseases. Digital polymerase chain reaction (dPCR), which is a revolutionized nucleic acid absolute quantitative analysis technology, plays a significant role in the detection of genetic material. However, the traditional threshold-based methods fail to obtain high-accuracy segmentation results and real-time performance from dPCR fluorescence images with uneven illumination. Therefore, we proposed a robust two-stage automatic thresholding method to deal with dPCR fluorescence images. This method adopts the background subtraction method and the improved Otsu method to extract reaction chambers of dPCR images in two stages. Especially for the second stage, the peak-weaken method based on the improved Otsu method greatly improves the real-time segmentation of uneven illumination regions. Our method significantly improves the accuracy and processing speed of the dPCR image segmentation compared to several mainstream methods. This method could effectively segment the reaction chambers of dPCR images in complex environments. The average precision rate is 99.71%, the execution time is 0.139 s. Experimental results demonstrate that our proposed strategy has superior segmentation performance for high-throughput dPCR fluorescence images with uneven illumination. [ABSTRACT FROM AUTHOR]

Photo-controlled method may improve the accuracy of fluorescent probes. Here, two new fluorescent probes HSP and MSP were designed based on naphthalimide and spiropyran. HSP exhibits a fluorescent emission at 540 nm after Human Serum Albumin (HSA) was added. Then with UV light irradiation, the spiropyran group of HSP is isomerized into the merocyanine, and the HSP/HSA hybrid displays red fluorescence emission at 610 nm, which demonstrats the probe have a unique fluorescence "double-check" mechanism to accurately detect HSA. As a comparison, a new probe MSP which structure similar to HSP was designed. Compared with HSP , the recognition effect of probe MSP on HSA is not obvious, which showed that the hydrophilic group hydroxyl displays an important influence on the response of the probe HSP to HSA. In addition, the HSP/HSA hybrid can also be used to detect SO 2 effectively. Most importantly, we have successfully applied HSP/HSA hybrid to image SO 2 in living cells. • The first case of hybrid by light-controlled method to identify SO 2. • The probe HSP can recognize HSA with "Double-Check" model. • Probe have good selectivity, low detection limit and avoid false positive interference. • The hydroxyl group of HSP is important and can bind to the amino acid residues of human serum albumin. [ABSTRACT FROM AUTHOR]

In living cells, cysteine (Cys) and bisulfite are involved in many important physiological processes. Their unbalance in vivo would lead to multiple diseases. So, it is vital to develop difuntional sensor for Cys and bisulfite. As we known, cysteine could metabolized into bisulfite by the metabolic processes of cysteine in the animal level. Therefore, we designed and synthesized a mitochondria-targeted long-wavelength ratio fluorescence sensor Z2 for Cys and bisulfite simultaneous detection. Z2 exhibitted excellent selectivity, good anti-interference, fast response and low detection limit. The sensor exhibited obviously two channels fluorescence response for Cys and bisulfite orderly. Z2 is widely used for imaging Cys and bisulfite in MCF-7 cells, zebrafish, and mice, and successfully imaging Cys metabolism in these livings. We hope this bifunctional ratio fluorescence sensor Z2 will be a useful tool to monitor Cys and SO 2 levels in living systems. Image 1 • A novel Mitochondria-targeted BET ratiometric fluorescent sensor were synthesized. • The sensor has excellent selectivity and show fast response to Cys and HSO 3 −. • The significant changes in color could be used for naked-eye detection. • It is the fastest example imaging Cys metabolism in living animals. [ABSTRACT FROM AUTHOR]

Abstract To assess the effects of food processing on the detection and quantification of transgenic rice TT51-1 in processed food by polymerase chain reaction (PCR) technology, we monitored the presence of TT51-1 components in rice crackers at different processing stages using conventional PCR, quantitative real-time PCR (qPCR), and droplet digital PCR (ddPCR) with standard or validated primers and probes. In conventional PCR, relatively longer amplification targets, such as the Bacillus thuringiensis (Bt) gene (301 bp) and the event-specific target (274 bp), were barely detected in baked, fried or microwaved samples. In qPCR, the amplification fluorescence signal was detected in boiled, dried, baked, and microwaved samples, but barely observed in fried samples. Conventional PCR with the same primers used in qPCR detected the corresponding shorter targets in all samples. The conventional PCR results were mainly consistent with the results of qPCR. The results indicate that food processing directly affects the detection of transgenic components, and suggest that relatively shorter fragments should be selected as the amplification targets for this type of analysis. We established qPCR and duplex ddPCR methods for quantifying TT51-1. The results of an orthogonal experiment indicated that the optimal conditions for TT51-1/PLD duplex ddPCR were 500/250 nM of primers/probe combined with 58 °C annealing temperature. Both methods were feasible for quantitative detection of TT51-1 in processed samples, with duplex ddPCR being a more attractive method for detecting transgenic components in processed food due to its stability, accuracy, PCR inhibitor resistance, and the lack of a need for reference materials. Highlights • Food processing affects the detection of GM components using PCR methods. • Shorter DAN targets were more suitable for detecting GM ingredient. • DNA extraction methods obtaining high quality DNA for downstream PCR analysis. • ddPCR more attractive than qPCR for detection of GM ingredient in processed food. • Annealing temperature plays a critical role in the performance of duplex ddPCR. [ABSTRACT FROM AUTHOR]

Two rhodamine based probes were designed and prepared for Sn 4+ via opening of the spiro-ring to give fluorescent and colored species. The two probes exhibited a strong fluorescence enhancement upon addition of Sn 4+ while showing almost no response to other cations in CH 3 CH 2 OH/HEPES buffer solution. Probe L 1 exhibited fast selectivity toward Sn 4+ and could be completed in 1 min. Fluorescence imaging experiments of Sn 4+ in living MGC803 cells demonstrated its value of practical applications in biological systems. [ABSTRACT FROM AUTHOR]