Plasmon-enhanced fluorescence combined with aptamer sensor based on Ag nanocubes for signal-amplified detection of berberine hydrochloride.

Plasmon enhanced fluorescent (PEF) with more "hot spots" play a critical role in signal amplified technology to avoid the intrinsic limitation of fluorophore which ascribed to a strong electromagnetic field at the tip structure. However, application of PEF technique to obtain a highly sensitive analysis of medicine was still at a very early stage. Herein, a simple but versatile Ag nanocubes (Agcubes)-based PEF sensor combined with aptamer (Agcubes@SiO2-QDs-Apt) was proposed for highly sensitive detection of berberine hydrochloride (BH). The distance between the plasma Agcubes and the red-emitted CdTe quantum dots (QDs) were regulated by the thickness of silica spacer. The three-dimensional finite-difference time-domain (3D-FDTD) simulation further revealed that Agcubes have a higher electromagnetic field than Ag nanospheres. Compared with PEF sensor, signal QDs-modified aptamer without Agcubes (QDs-Apt) showed a 10-fold higher detection limit. The linear range and detection limit of the Agcubes@SiO2-QDs-Apt were 0.1-100 µM, 87.3 nM, respectively. Furthermore, the PEF sensor was applied to analysis BH in the berberine hydrochloride tablets, compound berberine tablet and urine with good recoveries of 98.25-102.05%. These results demonstrated that the prepared PEF sensor has great potential for drug quality control and clinical analysis.

Prediction of Anti-rheumatoid Arthritis Natural Products of Xanthocerais Lignum Based on LC-MS and Artificial Intelligence.

AIMS: Employing the technique of liquid chromatography-mass spectrometry (LCMS) in conjunction with artificial intelligence (AI) technology to predict and screen for antirheumatoid arthritis (RA) active compounds in Xanthocerais lignum. BACKGROUND: Natural products have become an important source of new drug discovery. RA is a chronic autoimmune disease characterized by joint inflammation and systemic inflammation. Although there are many drugs available for the treatment of RA, they still have many side effects and limitations. Therefore, finding more effective and safer natural products for the treatment of RA has become an important issue. METHODS: In this study, a collection of inhibitors targeting RA-related specific targets was gathered. Machine learning models and deep learning models were constructed using these inhibitors. The performance of the models was evaluated using a test set and ten-fold cross-validation, and the most optimal model was selected for integration. A total of five commonly used machine learning algorithms (logistic regression, k-nearest neighbors, support vector machines, random forest, XGBoost) and one deep learning algorithm (GCN) were employed in this research. Subsequently, a Xanthocerais lignum compound library was established through HPLC-Q-Exactive- MS analysis and relevant literature. The integrated model was utilized to predict and screen for anti-RA active compounds in Xanthocerais lignum. RESULTS: The integrated model exhibited an AUC greater than 0.94 for all target datasets, demonstrating improved stability and accuracy compared to individual models. This enhancement enables better activity prediction for unknown compounds. By employing the integrated model, the activity of 69 identified compounds in Xanthocerais lignum was predicted. The results indicated that isorhamnetin-3-O-glucoside, myricetin, rutinum, cinnamtannin B1, and dihydromyricetin exhibited inhibitory effects on multiple targets. Furthermore, myricetin and dihydromyricetin were found to have relatively higher relative abundances in Xanthocerais lignum, suggesting that they may serve as the primary active components contributing to its anti-RA effects. CONCLUSION: In this study, we utilized AI technology to learn from a large number of compounds and predict the activity of natural products from Xanthocerais lignum on specific targets. By combining AI technology and the LC-MS approach, rapid screening and prediction of the activity of natural products based on specific targets can be achieved, significantly enhancing the efficiency of discovering new bioactive molecules from medicinal plants.

Chronic Sleep Deprivation Impairs Visual Functions via Oxidative Damage in Mice.

Sleep deprivation (SD) is a global public health burden, and has a detrimental role in the nervous system. Retina is an important part of the central nervous system; however, whether SD affects retinal structures and functions remains largely unknown. Herein, chronic SD mouse model indicated that loss of sleep for 4 months could result in reductions in the visual functions, but without obvious morphologic changes of the retina. Ultrastructural analysis by transmission electron microscope revealed the deterioration of mitochondria, which was accompanied with the decrease of multiple mitochondrial proteins in the retina. Mechanistically, oxidative stress was provoked by chronic SD, which could be ameliorated after rest, and thus restore retinal homeostasis. Moreover, the supplementation of two antioxidants, α-lipoic acid and N-acetyl-l-cysteine, could reduce retinal reactive oxygen species, repair damaged mitochondria, and, as a result, improve the retinal functions. Overall, this work demonstrated the essential roles of sleep in maintaining the integrity and health of the retina. More importantly, it points towards supplementation of antioxidants as an effective intervention strategy for people experiencing sleep shortages.

Tailored Polypyrrole Nanofibers as Ion-to-Electron Transduction Membranes for Wearable K+ Sensors.

Conductive polymers are recognized as ideal candidates for the development of noninvasive and wearable sensors for real-time monitoring of potassium ions (K+ ) in sweat to ensure the health of life. However, the low ion-to-electron transduction efficiency and limited active surface area hamper the development of high-performance sensors for low-concentration K+ detection in the sweat. Herein, a wearable K+ sensor is developed by tailoring the nanostructure of polypyrrole (PPy), serving as an ion-to-electron transduction layer, for accurately and stably tracing the K+ fluctuation in human sweat. The PPy nanostructures can be tailored from nanospheres to nanofibers by controlling the supramolecular assembly process during PPy polymerization. Resultantly, the ion-to-electron transduction efficiency (17-fold increase in conductivity) and active surface area (1.3-fold enhancement) are significantly enhanced, accompanied by minimized water layer formation. The optimal PPy nanofibers-based K+ sensor achieved a high sensitivity of 62 mV decade-1 , good selectivity, and solid stability. After being integrated with a temperature sensor, the manufactured wearable sensor realized accurate monitoring of K+ fluctuation in the human sweat.

MAP4Ks inhibition promotes retinal neuron regeneration from Müller glia in adult mice.

Mammalian Müller glia (MG) possess limited regenerative capacities. However, the intrinsic capacity of mammalian MG to transdifferentiate to generate mature neurons without transgenic manipulations remains speculative. Here we show that MAP4K4, MAP4K6 and MAP4K7, which are conserved Misshapen subfamily of ste20 kinases homologs, repress YAP activity in mammalian MG and therefore restrict their ability to be reprogrammed. However, by treating with a small molecule inhibitor of MAP4K4/6/7, mouse MG regain their ability to proliferate and enter into a retinal progenitor cell (RPC)-like state after NMDA-induced retinal damage; such plasticity was lost in YAP knockout MG. Moreover, spontaneous trans-differentiation of MG into retinal neurons expressing both amacrine and retinal ganglion cell (RGC) markers occurs after inhibitor withdrawal. Taken together, these findings suggest that MAP4Ks block the reprogramming capacity of MG in a YAP-dependent manner in adult mammals, which provides a novel avenue for the pharmaceutical induction of retinal regeneration in vivo.

Fluorogenic methodology for visualization of phase separation in chemical biology.

Phase separation is a common biological phenomenon in the liquid environment of organisms. Phase separation has been shown to be a key cause of many existing incurable diseases, such as the protein aggregates formed by phase separation of Alzheimer's Disease, Amyotrophic Lateral Sclerosis, Parkinson's disease, etc. Tracking the occurrence of phase separation in vivo is critical to many disease detection methods and solving many treatment problems. Its physicochemical properties and visual detection methods have flourished in the last few years in chemical biology, among which the fluorogenic toolbox has great application potential compared to the traditional detection methods that cannot visualize the phase separation process intuitively, but just show some parameters indirectly. This paper reviews the mechanism and disease correlation proven in recent years for phase separation and analyzes the detection methods for phase separation, including functional microscope imaging techniques, turbidity monitoring, macromolecule congestion sensing, in silico analysis, etc. It is worth mentioning that the qualitative and quantitative analysis of aggregates formed by phase separation using in vitro parameters has successfully provided basic physical and chemical properties for phase separation aggregates, and is an important cornerstone for researchers to carry forward the past and break through the existing technical shackles to create new in vivo monitoring methods such as fluorescence methodology. Crucially, fluorescence methods for cell microenvironment imaging based on different mechanisms are discussed, such as AIE-based probes, TICT-based probes and FRET-based probes, etc.

Surface-enhanced fluorescence for lipopolysaccharide analysis based on shell-isolated nanoparticle.

Lipopolysaccharide (LPS) as the component of cell membrane on gram-negative bacteria played a central role on inflammatory inducer to stimulate a multi-system host response. Herein, a surface-enhanced fluorescent (SEF) sensor was developed for LPS analysis based on shell-isolated nanoparticles (SHINs). The fluorescent signal of CdTe quantum dots (QDs) was amplified by silica shell-coated Au nanoparticles (Au NPs). The 3D finite-difference time-domain (3D-FDTD) simulation revealed that this enhancement was due to local electric field amplification. This method has a linear detection range of 0.1-20 µg/mL and a detection limit of 64 ng/mL for LPS. Furthermore, the developed method was successfully applied for LPS analysis in milk and human serum sample. The results indicated that the as-prepared sensor has significant potential for selective detection of LPS in biomedical diagnosis and food safety.

Plasmon-enhanced fluorescence for ellagic acid detection based on surface structure of gold nanoparticles.

Ellagic acid (EA), as a natural polyphenolic acid, is considered a naturally occurring inhibitor of carcinogenesis. Herein, we developed a plasmon-enhanced fluorescence (PEF) probe for EA detection based on silica-coated gold nanoparticles (Au NPs). A silica shell was designed to control the distance between silica quantum dots (Si QDs) and Au NPs. The experimental results indicated that an 8.8-fold fluorescence enhancement was obtained compared with the original Si QDs. Three-dimensional finite-difference time-domain (3D-FDTD) simulations further demonstrated that the local electric field enhancement around Au NPs led to the fluorescence enhancement. In addition, the fluorescent sensor was applied for the sensitive detection of EA with a detection limit of 0.14 µM. It can be used to detect EA in pomegranate rind with a recovery rate of 100.26-107.93%. It can also be applied to the analysis of other substances by changing the identification substances. These experimental results indicated that the probe provides a good option for clinical analysis and food safety.

Micro/Nano-Fabrication of Flexible Poly(3,4-Ethylenedioxythiophene)-Based Conductive Films for High-Performance Microdevices.

With the increasing demands for novel flexible organic electronic devices, conductive polymers are now becoming the rising star for reaching such targets, which has witnessed significant breakthroughs in the fields of thermoelectric devices, solar cells, sensors, and hydrogels during the past decade due to their outstanding conductivity, solution-processing ability, as well as tailorability. However, the commercialization of those devices still lags markedly behind the corresponding research advances, arising from the not high enough performance and limited manufacturing techniques. The conductivity and micro/nano-structure of conductive polymer films are two critical factors for achieving high-performance microdevices. In this review, the state-of-the-art technologies for developing organic devices by using conductive polymers are comprehensively summarized, which will begin with a description of the commonly used synthesis methods and mechanisms for conductive polymers. Next, the current techniques for the fabrication of conductive polymer films will be proffered and discussed. Subsequently, approaches for tailoring the nanostructures and microstructures of conductive polymer films are summarized and discussed. Then, the applications of micro/nano-fabricated conductive films-based devices in various fields are given and the role of the micro/nano-structures on the device performances is highlighted. Finally, the perspectives on future directions in this exciting field are presented.

Ratiometric fluorescence probe integrated with smartphone for visually detecting lipopolysaccharide.

A portable instrument-free detection method for lipopolysaccharide (LPS) analysis was developed based on dual-emission ratiometric fluorescence sensing system. Herein, red-emitting Au nanoclusters (Au NCs) were as reference probe, while blue-emitting fluorescent silica quantum dots (Si QDs) were as response probe. Additionally, the aptamer of LPS was covalently grafted to the surface of Si QDs in order to specific recognize the LPS. According to the changes of fluorescence intensityratio (FL ratio, I461 nm/I643 nm) with the concentrations of LPS, the linear equation was fitted with the range of 50-3000 ng/mL, and the limit of detection (LOD) was 29.3 ng/mL. As a practical application, this method was employed to analyze LPS in normal saline with the recovery rate of 97.7-103.8 %. The color picker platform in the smartphone was used to transform the detection picture to the process of Red, Green and Blue (RGB) for visual detection of LPS. The low-cost and easy-carry method reported here presents broad merits for the visually quantitative detection of LPS.

Chemiluminescence of doped carbon dots with H2O2-KMnO4 system for the detection of Cu2+ and tannin.

The carbon dots doped with chlorine and phosphorus (CDs-Cl,P) were used as chemiluminescence (CL) reagent for the sensitive detection of copper ions (Cu2+) and tannin (TA). The CDs-Cl,P was found to strongly enhance the reaction of H2O2 and KMnO4 in alkaline medium. The enhanced CL behavior of CDs-Cl,P was investigated and it was found that some radicals such as •OH, •O2- and 1O2 appeared in the CL reaction process. The participation of Cu2+ could result in an enhanced CL intensity of the CDs-Cl,P-H2O2-KMnO4 system due to the Cu2+-catalyzed decomposition of H2O2 resulting in more •OH generation. Therefore, the CDs-Cl,P-H2O2-KMnO4 system was used to selectively quantify Cu2+ in solution by CL emission. A linear increase was observed between CL intensity and Cu2+ concentration. The CDs-Cl,P-H2O2-KMnO4 system allowed the detection of Cu2+ down to lower concentration of 0.1 µM with a linear range of 0.2-60.0 µM. Moreover, TA as a common polyphenolic compound, could selectively decrease the CL signal of the CDs-Cl,P-H2O2-KMnO4-Cu2+ system due to its complexation with Cu2+. On this basis, the CL assay for TA was also developed. The detection limit was 0.14 µM and the linear range was from 5.0 µM to 100.0 µM. The proposed method was successfully applied to the determination of Cu2+ and TA in water, rice dumplings leaves, sodium copper chlorophyllin and wine samples with satisfactory results.

MoSDT1 triggers defense response through modulating phosphorylated proteins in rice.

KEY MESSAGE: MoSDT1, a rice blast fungus transcription factor, is as an inducer to activate defense response through mainly mediating phosphorylated proteins in rice. Pathogen effector proteins play a dual role in infecting the host or triggering a defense response. Our previous research found a Magnaporthe oryzae effector, MoSDT1, which could activate the rice defense response when it was overexpressed in rice. However, we still know little about the mechanisms on how MoSDT1 in vivo or in vitro influences the resistance ability of rice. Our results showed that decreased ROS and increased lignin contents appeared along with significant upregulation of defense-related genes, raffinose synthesis gene, and phenylalanine ammonialyase gene. Moreover, we revealed that the contents of lignin were increased, which was in accordance with the upregulation of its precursor phenylalanine gene despite the fact that the glutamate-/thiamine-responsive genes were inhibited in MoSDT1 transgenic rice, and these indicated that MoSDT1 triggered the defense system of rice in vivo. Interestingly, in vitro studies, we further found that MoSDT1 induced the defense system by ROS synthesis, callose deposition, PR gene expression and SA/JA synthesis/signal genes using the purified prokaryotic expression system in rice plants. In addition, this defense response was confirmed to be activated by the zinc finger domain of MoSDT1 via prokaryotic expression of MoSDT1 truncated mutants in rice plants. To elucidate the regulative effects of MoSDT1 on protein phosphorylation in rice, phosphoproteome analysis was performed in both MoSDT1-transgenic and wild type  rice. We found that MoSDT1 specifically up-regulated the expression levels of a few phosphorylated proteins, which were involved in multiple functions, such as biotic/abiotic stress and growth. In addition, the motifs in these specific proteins ranked the top among the top-five conserved motifs in the MoSDT1-transgenic rice. MoSDT1 played a crucial role in enhancing rice resistance by modulating several genes and signaling pathways.

Near-Infrared-Fluorescent Probe for Turn-On Lipopolysaccharide Analysis Based on PEG-Modified Gold Nanorods with Plasmon-Enhanced Fluorescence.

Lipopolysaccharide (LPS), as the major component of the outer membrane of Gram-negative bacteria, can trigger a variety of biological effects such as sepsis, septic shock, and even multiorgan failure. Herein, we developed a near-infrared-fluorescent probe for fluorescent turn-on analysis of LPS based on plasmon-enhanced fluorescence (PEF). Gold nanorods (Au NRs) modified polyethylene glycol (PEG) was used as PEF materials. Au NRs were prepared with different longitudinal surface plasmon resonance (LSPR), and their fluorescence enhancement was investigated. Three kinds of molecular weights (1000, 5000, and 10000) of polyethylene glycol (PEG) were employed to control the distance between the Au NRs and the fluorescence substances of cyanine 7 (Cy7). Experimental analysis showed that the enhancement was related to the spectral overlap between the plasmon resonance of Au NRs and the extinction/emission of fluorophore. The three-dimensional finite-difference time-domain (3D-FDTD) simulation further revealed that the enhancement was caused by local electric field enhancement. Furthermore, the probe was used for the ultrasensitive analysis of LPS with a detection limit of 3.85 ng/mL and could quickly distinguish the Gram-negative bacterium-Escherichia coli (E. coli) (with LPS in the membrane) from Gram-positive bacterium-Staphylococcus aureus (S. aureus) (without LPS), as well as quantitative determination of E. coli with a detection limit of 1.0 × 106 cfu/mL. These results suggested that the prepared probe has great potential for biomedical diagnosis and selective detection of LPS from different bacterial strains.

Morphine promotes microglial activation by upregulating the EGFR/ERK signaling pathway.

Although they represent the cornerstone of analgesic therapy, opioids, such as morphine, are limited in efficacy by drug tolerance, hyperalgesia and other side effects. Activation of microglia and the consequent production of proinflammatory cytokines play a key pathogenic role in morphine tolerance, but the exact mechanisms are not well understood. This study aimed to investigate the regulatory mechanism of epidermal growth factor receptor (EGFR) on microglial activation induced by morphine in mouse microglial BV-2 cells. In this research, BV-2 cells were stimulated with morphine or pretreated with AG1478 (an inhibitor of EGFR). Expression levels of cluster of differentiation molecule 11b (CD11b), EGFR, and phospho-EGFR were detected by immunofluorescence staining. Cell signaling was assayed by Western blot. The migration ability of BV-2 cells was tested by Transwell assay. The production of interleukin-1beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) in the cell supernatant was determined by ELISA. We observed that the expression of CD11b induced by morphine was increased in a dose- and time- dependent manner in BV-2 cells. Phosphorylation levels of EGFR and ERK1/2, migration of BV-2 cells, and production of IL-1ß and TNFα were markedly enhanced by morphine treatment. The activation, migration, and production of proinflammatory cytokines in BV-2 cells were inhibited by blocking the EGFR signaling pathway with AG1478. The present study demonstrated that the EGFR/ERK signaling pathway may represent a novel pharmacological strategy to suppress morphine tolerance through attenuation of microglial activation.

A switchable and signal-amplified aptasensor based on metal organic frameworks as the quencher for turn-on detection of T-2 mycotoxin.

A simple and low-cost fluorescence aptasensor was developed for rapid and sensitive signal amplification detection of T-2 mycotoxin (T-2). Dual-terminal-fluorescein amidite (FAM)-labeled aptamer (D-aptamer) acted as a recognition element and signal indicator. The metal organic frameworks (MOFs) of N, N'-bis(2-hydroxyethyl)dithiooxamidato copper (II) (H2dtoaCu) were as the quencher. The D-aptamer was initially adsorbed to the surface of H2dtoaCu, leading to efficient quenching of the aptasensor. Upon addition of T-2, the D-aptamer underwent a conformation change to form the T-2/T-2 aptamer complex, which induced the signaling probe to be released from the H2dtoaCu surface. Thus, the fluorescence intensity (FL) of the D-aptamer was recovered. Versus the single-terminal-FAM-labeled aptamer (S-aptamer), the D-aptamer showed a lower detection limit of 0.39 ng/mL. The aptasensor was also successfully applied to detect T-2 in corn and wheat samples with good recoveries.

Activation of the spinal EGFR signaling pathway in a rat model of cancer-induced bone pain with morphine tolerance.

Cancer-induced bone pain (CIBP) is considered to be one of the most difficult pain conditions to treat. Morphine, an analgesic drug, is widely used in clinical practice, and long-term use of morphine can lead to drug tolerance. Recent reports have suggested that inhibitors of epidermal growth factor receptor (EGFR) may have analgesic effects in cancer patients suffering from pain. Therefore, we sought to determine whether EGFR signaling was involved in morphine tolerance (MT) in a rat model of cancer-induced bone pain. In this study, Walker 256 mammary gland carcinoma cells were inoculated into the tibias of rats to provoke cancer-induced bone pain. Then, morphine was intrathecally administered twice daily for seven consecutive days to induce drug tolerance. We observed sustained increased in the protein levels of EGFR, p-EGFR, ERK1/2, and p-ERK1/2 during the development of morphine tolerance in rats with cancer-induced bone pain by western blotting. The EGFR level was significantly increased in the MT and CIBP + MT groups, and EGFR was colocalized with markers of microglia and neurons in the spinal cords of rats. Inhibition of EGFR by a small molecule inhibitor markedly attenuated the degree of morphine tolerance and decreased the number of microglia, and the protein levels of EGFR, p-EGFR, ERK1/2, and p-ERK1/2 were also reduced. In summary, our results suggest that the activation of the EGFR signaling pathway in spinal microglia plays an important modulatory role in the development of morphine tolerance and that inhibition of EGFR may provide a new therapeutic option for cancer-induced bone pain.

Gray Matter and Regional Brain Activity Abnormalities in Subclinical Hypothyroidism.

Background: Subclinical hypothyroidism (SCH) brain structure and resting state of functional activity have remained unexplored. Purpose: To investigate gray matter volume (GMV) and regional brain activity with the fractional amplitude of low-frequency fluctuations (fALFF) in subclinical hypothyroidism (SCH) patients before and after treatment. Material and Methods: We enrolled 54 SCH and 41 age-, sex-, and education-matched controls. GMV and fALFF of SCH were compared with controls and between pre- and post-treatment within SCH group. Correlations of GMV and fALFF in SCH with thyroid function status and mood scales were assessed by multiple linear regression analysis. Results: Compared to controls, GMV in SCH was significantly decreased in Orbital part of inferior frontal, superior frontal, pre-/postcentral, inferior occipital, and temporal pole gyrus. FALFF values in SCH were significantly increased in right angular, left middle frontal, and left superior frontal gyrus. After treatment, there were no significant changes in GMV and the local brain function compared to pre-treatment, however the GMV and fALFF of the defective brain areas were improved. Additionally, decreased values of fALFF in left middle frontal gyrus were correlated with increased mood scales. Conclusion: In this study we found that patients with SCH, the gray matter volume in some brain areas were significantly reduced, and regional brain activity was significantly increased. After treatment, the corresponding structural and functional deficiencies had a tendency for improvement. These changes may reveal the neurological mechanisms of mood disorder in SCH patients.

The disruption of the MAPKK gene triggering the synthesis of flavonoids in endophytic fungus Phomopsis liquidambaris.

Flavonoids, which are mainly extracted from plants, are important antioxidants and play an important role in human diseases. However, the growing market demand is limited by low productivity and complex production processes. Herein, the flavonoids biosynthesis pathway of the endophytic fungus Phomopsis liquidambaris was revealed. The mitogen-activated protein kinase kinase (MAPKK) of the strain was disrupted using a newly constructed CRISPR-Cas9 system mediated by two gRNAs which was conducive to cause plasmid loss. The disruption of the MAPKK gene triggered the biosynthesis of flavonoids against stress and resulted in the precipitation of flavonoids from fermentation broth. Naringenin, kaempferol and quercetin were detected in fed-batch fermentation with yields of 5.65 mg/L, 1.96 mg/L and 2.37 mg/L from P. liquidambaris for dry cell weigh using the mixture of glucose and xylose and corn steep powder as carbon source and nitrogen source for 72 h, respectively. The biosynthesis of flavonoids was triggered by disruption of MAPKK gene in P. liquidambaris and the mutant could utilize xylose.

A smartphone-combined ratiometric fluorescence probe for specifically and visibly detecting cephalexin.

A smartphone-combined dual-emission ratiometric fluorescence probe for specifically and visibly detecting cephalexin was first designed. In the probe, blue-emitting fluorescent carbon dots (CDs) was synthesized and covered with a layer of silica spacer. Red-emitting fluorescent CdTe QDs (r-QDs) was grafted onto the silica nanospheres as an analytical probe. Then, the cephalexin antibody was covalent grafted to the ratio sensor to increase the selectivity. The ratio of fluorescence intensity (FL) of r-QDs and CDs was quenched with the increasing concentration of cephalexin. The detection method has good linear response in the range of 1-500 µM and the detection limit was 0.7 µM. Then portable device based on smartphone detection was constructed according to the color change under UV lamp. The detection image was obtained through the smartphone camera, and the color picker APP installed in the smartphone captured the RGB value of the image. In addition, this method was also used to determine the amount of cephalexin in milk samples with recovery of 94.1%-102.2%. These results showed that it was a portable, simple and visible method to detect cephalexin in food analysis and environmental monitoring.

A nitrogen doped carbon dots-enhanced peroxynitrous acid chemiluminescence method for 2-naphthol detection.

A weak CL emission was initiated by peroxynitrous acid (PA) produced by the interaction of nitrite with hydrogen peroxide in sulphuric acid solution. In the presence of nitrogen doped carbon dots (NCDs), the CL intensity was enhanced significantly. The CL mechanism of the NCDs-PA system was studied using the CL spectrum, FL spectrum and the effect of radical scavengers. The NCDs-PA CL system was developed for the determination of 2-naphthol (2-NAP) based on its inhibition effect. The reduced CL intensity was proportional to the concentration of 2-NAP in the range from 0.3 to 20.0 µM and the detection limit was 48.0 nM. This method had been successfully applied to determine 2-NAP in environmental water samples with recoveries of 99.5-102.8%.