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Ochratoxin A (OTA) frequently contaminates grains and consequently threatens human health. Herein, we develop a regenerable signal probe and apply it to a Au-based screen-printed electrode module (SPE) for OTA determination. The signal probe, containing a structural covalent organic framework, gold nanoparticles (AuNPs), indicative methylene blue (MB), and a highly selective aptamer, is synthesized with hydrothermal and self-assembly methods. The SPE is permanently functionalized with Prussian blue (PB), AuNPs, and semicomplementary ssDNA. The signal probe, absorbed onto this SPE via hybridization, is competitively expelled by OTA, providing a ratiometric readout of Δ

Exosome-based liquid biopsies highlight potential utility in diagnosis and determining the prognosis of patients with cancer and other diseases. However, the existing techniques are severely limited for practical applications due to the complications of high cost, low sensitivity, tedious procedures, and large sample consumption. Herein, we report a microstructured optical fiber sensor for fast, sensitive, and accurate quantification of exosomes in blood samples of breast cancer patients. Numerical simulations are applied to demonstrate that hollow-core microstructured antiresonant fibers (HARFs) can stringently confine light in the fiber core, ensuring strong light-matter interaction and thus maximumly amplifying the signal. Taking this advantage, a AuNPs-dsDNA assembly containing gold nanoparticles, a recognizing DNA aptamer, and a fluorescent reporter DNA sequence is fabricated followed by immobilization on the fiber wall to form a AuNPs-dsDNA-HARF sensor. Cancer-derived exosomes can be recognized and captured in the fiber channel and generate dose-dependent fluorescent signals for quantification. The microfiber sensor demonstrates enhanced sensitivity and specificity, enabling the detection of single digits of exosome particles at the nanoliter sample level. In addition, by tracking exosome phenotypic changes, the proposed fiber sensor can facilitate precise drug treatment monitoring. This work provides a robust platform for exosome-based biopsy for cancer diagnosis and prediction of therapeutic outcomes.

Using boron as a test analyte, laser ablation (LA) solution sampling multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is proposed and validated as a fast method for isotopic analysis in natural liquids and digested samples without any prior purification process. We demonstrated that the solution reference standard can be used as a bracketing standard for in situ δ

Carbonyl stress caused by reactive carbonyl species (RCS) is closely related to various brain diseases. As the highly reactive, highly toxic, and lipophilic RCS, malondialdehyde (MDA) and formaldehyde (FA) could easily cross the blood-brain barrier (BBB) and induce protein dysfunction or cross-linking in the brain. Do MDA and FA coordinately regulate the physio-pathological processes of the brain? To answer the question, first of all, powerful identification and sensing tools are needed. However, competent probes for simultaneously analyzing MDA and FA in living brains are lacking, which originates from the following three challenges: (1) MDA and FA are difficult to distinguish due to their great similarity in structure and reactivity; (2) to achieve simultaneous and discriminable imaging, same excitation and different emissions are preferable; and (3) the detection of MDA and FA in living brains require the materials to pass through the BBB. Thus, we created a two-photon fluorescent agent, TFCH, for MDA/FA. The hydrazine group in TFCH could successfully differentiate MDA/FA at 440/510 nm under same excitation. Moreover, the lipophilic trifluoromethyl group (-CF

Revealing the relationship between reactive oxygen species (ROS) and levels of protein phosphorylation is of great significance for understanding the pathogenesis of diseases. Although mass spectrometry is used as a classical method for protein phosphorylation analysis, there are still some challenges to realize in vivo protein phosphorylation recognition. Herein, we designed and prepared an metal-organic framework (MOF)-based fluorescent nanoprobe with Zr(IV) and boronate ester as an active center, which achieved simultaneous recognition of ROS and phosphorylation sites. The ROS unit was constructed by 1,8-naphthalimide and boronate ester as a fluorophore and a recognition group, respectively. The specific interaction between Zr(IV) and a phosphate group was used to realize fluorescence imaging of phosphorylation sites. Using the advantages of two-photon property of the ROS recognition unit, the nanoprobe can effectively reduce the background fluorescence and thus improve the imaging sensitivity. Finally, the MOF-based nanoprobe was successfully applied to reveal the relationship between ROS and levels of phosphorylation in pneumonia mice, which illustrated that the ROS and phosphorylation levels in the process of pulmonary inflammation were obviously higher than those of the normal mice. This work provides feasible fluorescence tools that have important significance for revealing pathogenesis of diseases.

Idiopathic pulmonary fibrosis (IPF) has been characterized as a chronic inflammatory disease that leads to irreversible damage to pulmonary function. However, there is no specific IPF biomarker that can be used to distinguish IPF and not pneumonia. Endoplasmic reticulum (ER) stress is prominent in IPF. To search for a specific biomarker of IPF, we developed two ER-targeting two-photon (TP) fluorescent probes, TP

Iodide-adduct chemical ionization mass spectrometry (I-CIMS) is a widely used technique in the atmospheric chemistry community to detect oxygenated volatile organic compounds (OVOCs) in real time. In this work, we report the occurrence of secondary ion chemistry from interactions between a strong oxygen donor (such as O3 and peracids) and acidic OVOCs (such as carboxylic acids and organic hydroperoxides) in the ion-molecule reaction (IMR) region of I-CIMS. Such interactions can lead to acidic organic molecules (HA or HB) clustering with [IO]- (e.g., [HA + IO]-) and dimer adducts ([A + B + I]-), in addition to the well-known iodide clusters ([HA + I]-). This ion chemistry was probed using common chemical standards as well as the gas-phase oxidation products of α-pinene and isoprene in a flowtube reactor. The results show that secondary ion chemistry can lead to misinterpretations of molecular compositions and distributions of the gas-phase products and an overestimation of the elemental O/C ratio overall. Nevertheless, the varying degrees of signal change in response to the secondary ion chemistry might be a clue to inform OVOCs' functionalities. Specifically, in the α-pinene ozonolysis system, the extents of ion signal reduction in the presence of additional acids in the IMR suggest that C9H14O4 produced in the gas phase is a peracid, rather than the often-assumed pinic acid. Thus, we suggest that the potential application of the secondary ion chemistry to inform organic functionalities is promising, which could help better understand the molecular compositions of gas-phase OVOCs and the reaction mechanisms therein.

Drug-induced liver injury (DILI) is the most common reason for the post-marketing withdrawal of drugs. Poor understanding of the mechanisms of DILI presents a large challenge in clinical diagnosis. Previous evidences indicate a potential relationship between reactive nitrogen species (RNS) and DILI. Hence, we developed two specific probes, Golgi-HNO and Mito-HNO, for the multicolored and simultaneous in situ imaging of nitroxyl (HNO) in the Golgi apparatus and mitochondria, respectively. We discovered a significant rise in HNO levels in the livers of mice with DILI, which means that for the first time, we revealed a positive correlation between HNO levels and DILI. Based on changes in the HNO level, we also successfully explored the extent of liver damage induced by an anticarcinogen, bleomycin. In addition, we uncovered catalase was involved in HNO synthesis, which is the unprecedented function of catalase. These findings demonstrate that HNO is an ideal biomarker for DILI diagnosis, and Golgi-HNO and Mito-HNO are ideal fluorescent probes to study in situ HNO changes in various physiological and biochemical processes.

Current diagnosis of depression rests on the symptoms, so it still lacks objective criteria. Meanwhile, existing treatment of depression is dominated by antidepressants, which produce troublesome side effects and usually require months to achieve effect. Therefore, more reliable diagnostic criteria and effective therapy are urgently needed. Some core hallmarks in the etiology of depression have been established, including declined neurotransmitters and inflammatory responses, manifesting in oxidative stress. Thus, we fabricated a HClO-triggered multifunctional fluorescence platform (MB-Rs) for simultaneous neurotransmitter/antidepressant delivery and efficacy evaluation. In MB-Rs, although a urea linkage could be specifically cut off by HClO, methylene blue (MB) endowed with excellent anti-inflammatory and optical properties was covalently linked with neurotransmitters (dopamine or 5-hydroxytryptamine) or antidepressants (fluoxetine). Encountering excess HClO in the brain of mice with depression, MB-Rs released corresponding antidepressants and MB with anti-inflammatory and bright fluorescence. By relieving oxidative stress, inflammation, and coinstantaneous increasing neurotransmitters, MB-Rs elicited better antidepressant response and fewer side effects compared with clinical antidepressants. Furthermore, MB-Rs successfully evaluated the efficacy of antidepressants in mice based on HClO-induced fluorescence. Therefore, this work provides a promising platform for depression diagnosis and treatment.

Homocysteine (Hcy) is one of the important biomarkers of clinical diagnosis, which is closely related to the occurrence and development of many diseases. Current analysis methods have difficulties in detecting Hcy in cells and living organisms. As a powerful technique, fluorescence methods combined the laser confocal imaging technology can achieve real-time visual tracking in cells and in vivo. Herein, we establish a conjugated copolymer-based fluorescence nanosensor (DPA-PFNP-Cu(II)) using the connected 2,7-dibromofluorene and 4,7-bis (2-bromothiophen-5-yl)-2-1-3-benzothiadiazole as the main chain. The competitive coordination between Hcy and Cu(II) allows the fluorescence of the polymer off to on. Finally, the nanosensor is applied for in situ imaging of Hcy levels in the kidney and liver of diabetic mice and is found that Hcy levels were positively correlated with the degree of diabetes. Notably, the depth of tissue penetration of the nanosensor enables Hcy detection of the liver and kidney through in vivo imaging without damage. Two-photon imaging and in vivo imaging achieve consistent results, which correct each other, improving the accuracy of the test result. The present works provide a new imaging technique for studying the occurrence and development of diabetes and screening of new drugs for treatment at the living level.

Closely related to multiple chronic inflammation, especially type-2 diabetes (T2D), methylglyoxal (MGO) may be a potential key to visualize disease progression and treatment effects. On the other hand, lack of convenient and fast analytical methods cannot afford accurate MGO quantitative evaluation. In this work, an activatable second near-infrared region (NIR-II) fluorescent probe TDTCD was synthesized and its reaction mechanism with MGO was discussed. The desired NIR-II product preferred response solvents with small polarity. A novel activatable nanoprobe, MG-SLNP, for MGO was then constructed based on rational packaging to provide a local nonpolar microenvironment. The hydrophobic core of nanoparticles not only successfully improved the stability and water solubility but also greatly promoted the response rate while reacting with MGO. The comparison between NIR-II fluorescence and the traditional high-performance liquid chromatography method for T2D blood samples was discussed. A high-resolution viewing window, quick response, and good biocompatibility led to a satisfactory signal-to-noise ratio of MG-SLNP for real-time MGO bio-detection and imaging in vivo.

Hyperthyroidism-induced liver injury is quite common in clinical settings. Therefore, developing rapid and simple methods for the assessment of hyperthyroid liver injury is of great significance. Considering phosphorus metabolism is disordered because of hyperthyroidism, and the hyperthyroid liver injury is closely related to the abnormal level of glutathione (GSH). Thus, development of a new method that can simultaneously detect changes in blood phosphorus and GSH levels of serum, liver, kidney, and other organs to assess the degree of hyperthyroid liver injury is necessary for clinical medical research. Herein, a novel fluorescent metal-organic frameworks (MOFs) nanoprobe using the UiO-66(OH)2 as core and Cu-MOFs as shell was designed and synthesized. Through the specific action between Zr (IV) and phosphate, and the combine interaction of MOFs active center Cu (II) and GSH, high sensitivity and specific fluorescence detection of phosphate and GSH were achieved, respectively. Finally, the nanosensor was applied for evaluating different degrees of hyperthyroid liver injury in mice models and realized the monitoring of serum, liver, kidney, and other organs' blood phosphorus and GSH levels, and found that the levels of phosphate and GSH in serum were negatively correlated with the degree of hyperthyroid liver injury, while the changes of phosphate and GSH levels in the liver and kidney organs were positively correlated with the degree of hyperthyroid liver injury. In general, the present works provide a new way to effectively evaluate liver injury induced by hyperthyroidism in the early clinical stage.

Depression is immensely attributed to the overactivation of N-methyl-d-aspartic acid (NMDA) receptor in the brains. As regulatory binding partners of NMDA receptor, both Zn2+ and H+ are intimately interrelated to NMDA receptor's activity. Therefore, exploring synergistic changes on the levels of Zn2+ and H+ in brains will promote the knowledge and treatment of depression. However, the lack of efficient, appropriate imaging tools limits simultaneously tracking Zn2+ and H+ in living mouse brains. Thus, a well-designed dual-color fluorescent probe (DNP) was fabricated for the simultaneous monitoring of Zn2+ and H+ in the brains of mice with depression. Encountering Zn2+, the probe evoked bright blue fluorescence at 460 nm. Meanwhile, the red fluorescence at 680 nm was decreased with H+ addition. With blue/red dual fluorescence signal of DNP, we observed the synchronous increased Zn2+ and H+ in PC12 cells under oxidative stress. Notably, in vivo imaging for the first time revealed the simultaneous reduction of Zn2+ and pH in brains of mice with depression-like behaviors. Further results implied that the NMDA receptor might be responsible for the coinstantaneous fluctuation of Zn2+ and H+ during depression. Altogether, this work is conducive to the knowledge of neural signal transduction mechanisms, advancing our understanding of the pathogenesis in depression.

Elucidating the relationship between glycosylation and phosphorylation of protein post-translational modifications is of great significance for understanding most diseases. Mass spectrometry has be...

Diacetoxyscirpenol (DAS) is a type A trichothecene mycotoxin with low molecular weight, and with respect to its toxicity and the occurrence in food and feed, it is known as a potential risk for public and animal health. In the present study, first, a sensitive and specific monoclonal antibody (5E7) was developed. Then, the antibody was applied to develop a competitive-type pressure-dependent immunosensor (CTPDI). The Au@PtNP was synthesized and labeled with goat antimouse antibody (Au@PtNPs-IgG). Finally, the concentration of DAS was negatively correlated with the pressure signal. In the presence of optimal conditions, matrix-matched calibration curves were plotted for wheat samples, in which an optimal IC50 value (half maximal inhibitory concentration) of 3.08 ng/g was achieved. The CTPDI was further applied to detect natural and blind wheat samples, and validation was carried out by liquid chromatography-tandem mass spectrometry. The results showed that CTPDI was highly appropriate and accurate for detection of DAS in wheat.

Drug-induced liver injury (DILI) can cause liver failure and even death in severe cases, gravely threatening human health. The treatment of DILI remains a clinical challenge, mainly due to the lack of efficient and accurate diagnosis. Therefore, developing an accurate diagnosis approach is imperative to boost the timely treatment for DILI. As the primary organ of iron storage, liver's functions are tightly linked to iron homeostasis. Thus, monitoring iron homeostasis is promising for the diagnosis and treatment of DILI. Hence, we reported a new near-infrared fluorescent probe (LCy7) that enables real-time and in vivo visualizing of Fe2+ in drug-induced liver injury. In this design, Fe2+ would bind to the N4O ligand in LCy7 and conduce to the C-O bond broken in the presence of O2, which restore the masked QCy7 emitting luminous near-infrared fluorescence. Utilizing LCy7, the increase in Fe2+ was distinctly witnessed in hepatocytes under endoplasmic reticulum stress by acetaminophen (APAP) stimulation. In vivo near-infrared fluorescence imaging revealed the conspicuous rise in Fe2+ in the liver of mice during APAP-induced liver injury. We further unprecedentedly disclosed that endoplasmic reticulum stress was accompanied by the overload of Fe2+ in injured liver of these mice. Collectively, this work will facilitate a greater understanding of the pathogenesis of DILI, and also provide a powerful new tool for DILI diagnosis and treatment.

The accurate detection of tumorous methylglyoxal (MGO) and its detoxifier glyoxalase 1 (GLO1) in living systems is critical for understanding their roles in tumor initiation and progression. To date, the in situ fluorescence detection of endogenous MGO and GLO1 in tumor has not been reported. Herein we developed a near-infrared (NIR) fluorescent probe MEBTD to specifically detect tumorous MGO. Compared with previously reported MGO fluorescent probes, MEBTD exhibits several distinct advantages, including NIR emission, high selectivity with an MGO detection limit of 18 nM, and a 131-fold off-on ratio. The probe could sense GLO1 activity and monitor the therapeutic effect of GLO1 inhibitors by imaging tumorous MGO in a both a real-time and in situ manner, demonstrating that the biological effect of GLO1 inhibitors is dependent on the GLO1 activity. Furthermore, MEBTD enables the visualization of tumorous MGO induced by GLO1 inhibitors in vivo. To the best of our knowledge, MEBTD is the first NIR fluorescent probe for specifically imaging tumorous MGO in living animals, indicating the promising potential for tumor diagnosis and therapeutic evaluation.

The analysis of ribonucleic acid (RNA) plays an important role in the early diagnosis of diseases and will greatly benefit patients with a higher cure rate. However, the low abundance of RNA in physiological environments requires ultrahigh sensitivity of a detection technology. Here, we construct a portable and smart-phone-controlled biosensing platform based on disposable organic electrochemical transistors for ultrasensitive analysis of microRNA (miRNA) biomarkers within 1 h. Due to their inherent amplification function, the devices can detect miRNA cancer biomarkers from little-volume solutions with concentrations down to 10–14 M. The devices can distinguish blood miRNA expression levels at different cancer stages using a 4T1 mouse tumor model. The technique for ultrasensitive and fast detection of RNA biomarkers with high selectivity opens a window for mobile diagnosis of various diseases with low cost.

Peroxisome proliferator-activated receptor alpha (PPAR-a) is a crucial nuclear transcription regulator of lipid metabolism, which is closely associated with the initiation and development of nonalcoholic fatty liver disease (NAFLD). Because PPAR-a can directly decide the level of peroxisomal metabolic enzymes, its changes might directly cause variations in peroxisomal polarity. Therefore, we developed a new two-photon fluorescence imaging probe, PX-P, in which the triphenylamine and cyanide moieties can real-time sense peroxisomal polarity changes. Using PX-P, we observed a prominent decrease in the peroxisomal polarity in the liver of mice with NAFLD for the first time. More importantly, we discovered that intracellular excessive peroxynitrite (ONOO-) and hydrogen peroxide (H2O2) underwent nitrification and oxidation, respectively, with various sites of PPAR-a. Interestingly, the key site of PPAR-a was nitrated by a low concentration of ONOO- rather than being oxidized by the high level of H2O2. These drastically reduced the activity of PPAR-a, accelerating the occurrence of NAFLD. Moreover, through activating PPARs with pioglitazone, peroxisomal polarity markedly increased compared with that of NAFLD. Altogether, our work presents a new approach for the early diagnosis of NAFLD and identifies potential therapeutic targets.

Nitric oxide (NO)-based cancer therapy has attracted much attention in recent years owing to its broad effects on cancer. Low concentrations of NO stimulate cancer cell progression, while its higher levels induce cell apoptosis, and thus, it has motivated the development of probes for in situ NO release monitoring. In this work, a galactose-modified benzothiadiazole-based fluorescent probe (GalNONP/C) was synthesized as both a NO-responsive nanoprobe and NO prodrug carrier. The probe exhibited far-red emission in the range from 550 to 800 nm, and the response showed acidity preference. The galactose on the probe enabled selective targeting of hepatocellular carcinoma (HCC) cells by binding to the asialoglycoprotein receptor (ASGPR) on the cell surface. The probe also delivered low-molecular weight NO prodrug JS-K into cells and monitored the real-time release of the generated NO. Furthermore, in vivo NO imaging with tumor targeting was demonstrated in HCC orthotopic transplantation nude mice and liver sections. Compared with the control experiment using a probe without NO prodrug loading, higher fluorescence response of NO was detected in the cell (3.0 times) and liver slices of the HCC tumor model (2.7 times). This strategy may pave the way to develop nanoprobes for in situ NO monitoring and therapy evaluation in NO-related cancer therapy.

The variation of amyloid β peptide (Aβ) concentration and Aβ aggregation are closely associated with the etiology of Alzheimer's diseases (AD). The interaction of Aβ with the monosialoganglioside-rich neuronal cell membrane has been suggested to influence Aβ aggregation. Therefore, studies on the mechanism of Aβ and sialic acids (SA) interaction would greatly contribute to better understanding the pathogenesis of AD. Herein, we report a novel approach for Aβ-SA interaction analysis and highly sensitive Aβ detection by mimicing the cell surface presentation of SA clusters through engineering of SA-modified peptide nanofiber (SANF). The SANF displayed well-ordered 1D nanostructure with high density of SA on surface. Using FAM-labeled Aβ fragments of Aβ

In this study, a simple and effective method for the simultaneous analysis of Cl, Br, and I in geological materials based on NH4HF2 digestion in open vessels (Savillex Teflon vials) is proposed. It is very interesting to note that Cl, Br, and I are not lost during NH4HF2 digestion at temperatures of 200-240 °C for 0.5-12 h in open vessels. This should be related to the alkaline atmosphere environment caused by the NH3 produced during NH4HF2 digestion, which suppresses the volatilization loss of Cl, Br, and I. A 100 mg sample of geological materials can be completely digested by using 400 mg of NH4HF2 at 220 °C for 2 h in Savillex Teflon vials. The use of new Savillex Teflon vials significantly reduced the procedural blanks of halogens compared with the old Savillex Teflon vials. The developed method was successfully applied to the simultaneous determination of Cl, Br, and I in a series of international geological reference materials. Most of the results were found to be in reasonable agreement with values reported in the literature. This simple, rapid, effective, and economical analytical method will significantly promote the development of halogen geochemistry.

Depression is associated with decreased expression of brain-derived neurotrophic factor (BDNF) which assembled in Golgi apparatus. The changes might be closely related to variation in Golgi apparatus polarity. Thus, developing a nondestructive method to detect polarity in living cells and in vivo can facilitate accurate diagnosis and prognosis of depression. Herein, we created a new near-infrared Golgi-targetable fluorescent probe (Golgi-P) in which the merocyanine and benzoyl difluoroboronate moieties sense polarity changes. Golgi-P exhibited a decrease in fluorescence intensity and red-shift of maximum emission wavelength as the increase in polarity. Using Golgi-P, we discovered distinctly higher polarity in brains of mice with depression phenotype for the first time. Furthermore, our results disclosed that the elevation of polarity could due to the reduced synthesis of BDNF. Altogether, this study offers a new strategy for the accurate diagnosis of depression.

Multiclass chemical contamination of food has aroused ever-increasing attention due to the increasingly common findings of the co-occurrence of multiclass contamination, such as mycotoxin (aflatoxin M1, AFM1) and illegal additive (melamine, MEL). In the present study, a rapid, ultrasensitive detection paper was developed on the basis of a unique bridge-antibody label to realize on-site simultaneous detection of AFM1 and MEL in milk. This detection paper used the bridge-antibody label on fluorescent particles (i.e., the fluorescent Eu nanoparticles were first conjugated with polyclonal antibodies and then with monoclonal antibodies). Dramatically enhanced sensitivity was found, probably due to the increase in immobilization of efficient monoclonal antibodies onto microspheres. Under optimal conditions, the lower limits of detection were 0.009 and 0.024 ng/mL for AFM1 and MEL in milk, respectively, in comparison with similar works. Moreover, the cutoff values were 0.4 and 150 ng/mL for AFM1 and MEL, respectively. The recoveries ranged from 88.7% to 105.0% for AFM1 and from 84.6% to 117.7% for MEL, with relative standard deviations (RSDs) of 0.5-9.9% during the intraday and interday experiments. Comparison experiments conducted using the detection paper, HPLC, and UPLC-MS/MS found excellent agreement in the simultaneous detection of AFM1 and MEL in milk. This proposed method can be extensively employed for simultaneous monitoring of multiclass chemical contaminants to ensure food safety.

Aflatoxins, highly toxic and carcinogenic to humans, are synthesized via multiple intermediates by a complex pathway in several Aspergilli, including Aspergillus flavus. Few analytical methods are available for monitoring the changes in metabolite profiles of the aflatoxin biosynthesis pathway under different growth and environmental conditions. In the present study, we developed by a D-optimal mixture design a solvent system, methanol/dichloromethane/ethyl acetate/formic acid (0.36/0.31/0.32/0.01), that was suitable for extracting the pathway metabolites. The matrix effect from dilution of cell extracts was negligible. To facilitate the identification of these metabolites, we constructed a fragmentation ion library. We further employed liquid chromatography coupled with high-resolution mass spectroscopy (UHPLC-HRMS) for simultaneous quantification of the metabolites. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.002-0.016 and 0.008-0.05 μg/kg, respectively. The spiked recovery rates ranged from 81.3 to 100.3% with intraday and interday precision less than 7.6%. Using the method developed to investigate the time-course aflatoxin biosynthesis, we found that precursors, including several possible toxins (with a carcinogenic group similar to aflatoxin B1), occurred together with aflatoxin, and that production increased rapidly at the early growth stage, peaked on day four, and then decreased substantially. The maximum production of aflatoxin B1 and aflatoxin B2 occurred 1 day later. Moreover, the dominant branch pathway was the one for aflatoxin B1 formation. We revealed that the antiaflatoxigenicity mechanism of Leclercia adecarboxylata WT16 was associated with a factor upstream of the aflatoxin biosynthesis pathway. The design strategies can be applied to characterize or detect other secondary metabolites to provide a snapshot of the dynamic changes during their biosynthesis.

Hepatic ischemia-reperfusion (IR) injury is a severe pathophysiological event during liver surgery or transplantation and could lead to liver failure or even death. The energy supply of mitochondria plays an essential role in preventing IR injury. Mitochondrial DNA (mtDNA) is involved in maintaining the balance of energy by participating in an oxidative phosphorylation process. However, the exact relationship between IR and mtDNA remains unclear by reason of the lack of an accurate real-time analysis method. Herein, we fabricated a mitochondria-targeting fluorescent probe (mtDNA-BP) to explore mtDNA stability and supervise the changes in mtDNA in IR liver. By virtue of pyridinium electropositivity and suitable size, mtDNA-BP could accumulate in mitochondria and insert into the mtDNA groove, which made mtDNA-BP fluoresce strongly. This is attributed to the reduction of the intramolecular rotation energy loss that is restricted by DNA. By in situ fluorescence imaging, we observed in real time that mtDNA damage was aggravated by deteriorating IR injury, so the ROS-mtDNA-mediated IR damage signal pathway was speculated. Furthermore, on the basis of mtDNA-BP real-time response capability for mtDNA, we established a drug-screening method for inhibiting IR injury and found superior therapeutic performance of two potential drugs: pioglitazone and salidroside. This work contributes to our understanding of mtDNA-related disease and provides a new drug analysis method.

Homocysteine (Hcy) is one of the important biomarkers of clinical diagnosis, which is closely related to the occurrence and development of many diseases. Current analysis methods have difficulties in detecting Hcy in cells and living organisms. As a powerful technique, fluorescence methods combined the laser confocal imaging technology can achieve real-time visual tracking in cells and

Hyperthyroidism-induced liver injury is quite common in clinical settings. Therefore, developing rapid and simple methods for the assessment of hyperthyroid liver injury is of great significance. Considering phosphorus metabolism is disordered because of hyperthyroidism, and the hyperthyroid liver injury is closely related to the abnormal level of glutathione (GSH). Thus, development of a new method that can simultaneously detect changes in blood phosphorus and GSH levels of serum, liver, kidney, and other organs to assess the degree of hyperthyroid liver injury is necessary for clinical medical research. Herein, a novel fluorescent metal-organic frameworks (MOFs) nanoprobe using the UiO-66(OH)

A new photoelectrochemical imaging method termed scanning electrochemical photometric sensor (SEPS) is proposed in this work. It was derived from light-addressable potentiometric sensor (LAPS) and scanning photoinduced impedance microscopy (SPIM) using a front-side laser illumination at a field-effect structure. When the laser beam scans across the sensor substrate, local photocurrent changes at inversion due to the light absorption of analytes can be recorded. It will be shown that SEPS could be used for label-free living cell imaging with micro-resolution as well as real-time quantitative absorption analysis, which would broaden the applications of traditional LAPS/SPIM from potentiometric/impedance measurements to local optical analysis.

Development of probes for accurate sensing and imaging of biometals in situ is still a growing interest owing to their crucial roles in cellular metabolism, neurotransmission, and apoptosis. Among them, Zn2+ and Cu2+ are two important cooperative biometals closely related to Alzheimer's disease (AD). Herein, we developed a multifunctional probe based on self-assembling peptide nanoribbon for ratiometric sensing of Zn2+, Cu2+, or Zn2+ and Cu2+ simultaneously. Uniform peptide nanoribbon (AQZ@NR) was rationally designed by coassembling a Zn2+-specific ligand AQZ-modified peptide (AQZKL-7) with peptide KL-7. The nanoribbon further combined with Cu2+-sensitive near-infrared quantum dots (NIR QDs) and Alexa Fluor 633 as an inner reference molecule, which was endowed with the capability for ratiometric Zn2+ and Cu2+ imaging at the same time. The peptide-based probe exhibited good specificity to Zn2+ and Cu2+ without interference from other ions. Importantly, the nanoprobe was successfully applied for noninvasive Zn2+ and Cu2+ monitoring in both living cells and zebrafish via multicolor fluorescence imaging. This gives insights into the dynamic Zn2+ and Cu2+ distribution in an intracellular and in vivo mode, as well as understanding the neurotoxicity of high concentration of Zn2+ and Cu2+. Therefore, the self-assembled nanoprobe shows great promise in multiplexed detection of many other biometals and biomolecules, which will benefit the diagnosis and treatment of AD in clinical applications.

Golgi pH homeostasis affects many different biological processes, including glycosylation. Recent studies have demonstrated that transmembrane protein 165 (TMEM165) deficiency leads to Golgi glycosylation abnormalities by disturbing Golgi pH homeostasis. However, due to the lack of specific tools to measure Golgi pH in situ, evidence for TMEM165 involvement in H+ transport in the Golgi apparatus is still absent. Herein, the photoacoustic and fluorescent dual-mode probe CPH was developed for ratiometric detection of Golgi pH. CPH was proved to accumulate in the Golgi apparatus and reversibly image Golgi pH in real-time with high sensitivity in cells. Furthermore, we found that the absence of TMEM165 influenced H+ equilibrium and caused Golgi apparatus acidification. Our work provides strong evidence that TMEM165 regulates Golgi pH homeostasis. Moreover, we believe that CPH has the potential to be a practical tool to monitor Golgi pH in various biological processes.

Cerebral ischemia reperfusion injury (CIRI) is closely related to lipid peroxidation. Malondialdehyde (MDA), as a biomarker of lipid peroxidation, is prone to addition with biomacromolecules, resulting in a secondary cerebral injury. However, desirable tools for in vivo-determining cerebral MDA are scarce. Thus, we devised innovative polymer carbon dots carbonized by benzoyl hydrazine and named them BH-PCDs. BH-PCDs covered with hydrazine groups directly form from one-pot synthesis. The functional nanoparticle specifically identifies MDA via a photoinduced electron transfer (PET) mechanism from other similar biological species, especially reactive carbonyl species. BH-PCDs afforded several valuable traits of a simple preparation, a large two-photon absorption cross section, and exceptional biocompatibility, as well as the ability of traversing the blood-brain barrier. Relying on BH-PCDs, we real-time portrayed the increased cerebral MDA under CIRI. Furthermore, combining with a commercial indicator of the superoxide anion (O2•-), an O2•--regulated MDA level under CIRI was visualized in vivo. Moreover, we demonstrated MDA inactivated glutamine synthetase under CIRI, mediating the glutamate level. Overall, we provide a perspective nanolight serviceable for treating CIRI, which could reveal the physiopathology mechanism of brain MDA.

The U–Pb geochronologic analysis of accessory minerals has played an important role in Earth and solar system science in constraining the ages of a wide variety of rocks and minerals. Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) is one of the most popular techniques for U–Pb geochronologic analysis. Currently, the significant matrix effects observed between different accessory minerals and the lack of high-quality standards for many minerals of interest are the major limitations of its geochronological applications. In this study, we investigated the effects of the addition of oxygen, nitrogen, and water vapor before and after the ablation cell on the accuracy of the U–Pb dating of different minerals (e.g., zircon, monazite, titanite, and xenotime) by LA-ICP-MS. We found that the addition of water vapor, unlike that of oxygen and nitrogen, before the ablation cell can significantly suppress the matrix effects on U–Pb dating. The deviations of the measured 206Pb/238U ratios in the...

To accurately monitor the variations of lysosomal nitric oxide (NO) under physiological condition remains a great challenge for understanding the biological function of NO. Herein, we developed a new chemotype probe, namely, MBTD, for acid-promoted and far-red fluorescence imaging of lysosomal NO in vitro and ex vivo. MBTD was rationally designed by incorporating o-phenylenediamino (OPD) moiety into the donor-acceptor-donor (D-A-D) type fluorophore based on a dual intramolecular charge transfer (ICT) mechanism. Compared to previously reported OPD-based NO probes, MBTD displays several distinct advantages including large stroke shift, huge on-off ratio with minimal autofluorescence, and high NO specificity. Particularly, MBTD exhibits an acid-promoted response to NO with high acid tolerance, which greatly improves the spatial resolution to lysosomal NO by excluding the background noise from other nonacidic organelles. Furthermore, MBTD displayed much longer-lived and more stable fluorescence emission in comparison with the commercialized NO probe. MBTD was employed for ratiometric examination of the exogenous or endogenous NO of macrophages. More importantly, MBTD was able to detect the variation of lysosomal NO level in an acute liver injury mouse model ex vivo, implying the potential of MBTD for real-time monitoring the therapeutic efficacy of drug candidates for the treatment of acute liver injury. MBTD as a novel type of NO probe might open a new avenue for precisely sensing lysosomal NO-related pathological and therapeutic process.

Severe atmospheric haze caused by industrial pollution has severely affected human health and led to the increasing incidence of cardiopulmonary diseases, including pneumonia. Conventional methods for diagnosis of pneumonia are complicated and tedious, and current clinical imaging techniques might cause organ injuries to some extent. Therefore, an accurate, fast, and intact imaging method must be developed to diagnose pneumonia in the early stages. In this study, we propose a new two-photon fluorescence probe, named as ASPC, for detection of the activity of the inflammatory biomarker LTA4H through specific recognition and cleavage of amides containing the unnatural amino acid l-AspBzl. The activity of LTA4H in the lung tissues of mice was rapidly and accurately monitored for the first time and could be an indicator for diagnosis of pneumonia. The severity of pneumonia in mice caused by haze particulate was determined through imaging the activity of LTA4H as biomarker and confirmed using a commercial ELISA...

To capture both epithelial and mesenchymal subpopulations of CTCs at different metastatic stages of PCa patients, here we constructed a novel dual-antibody-functionalized microfluidic device by employing antibodies against PSMA and EpCAM. In vitro experiments with the dual capture system for capturing both LnCAP and LnCAP-EMT cells have shown significantly enhanced capture efficiency as compared to that of the EpCAM single capture system. Furthermore, the dual capture system could successfully identify CTCs in 20 out of 24 (83.3%) PCa patients, and the CTCs counts from the dual capture system were statistically correlated with the TNM stage of patients ( P0.05), while conventional diagnostic methods, such as serum PSA level and Gleason score, failed to correlate to patient TNM stages. To further explore potential clinical application of our dual capture system, captured CTCs were recovered and subjected to qRT-PCR to quantify known factors involved in PCa development and therapy. The results demonstrated that the combined detection of SChLAP1 and PSA in CTCs is a potential marker for identifying patients with metastatic PCa, while detection of AR and PD-L1 in CTCs may have the potential to determine the sensitivity of PCa patients to androgen deprivation therapy and immunotherapy, respectively. Taken together, the dual-antibody-functionalized microfluidic device established in our study overcomes the limitations of some CTC capture platforms that only detect epithelial or mesenchymal CTCs in PCa patients, and detection of the PCa-related RNA signatures from purified CTCs holds great promise to offer warnings for early metastasis of PCa and may provide guidance for therapy decisions.

A versatile and sensitive platform for label-free bioanalysis has been proposed on the basis of attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) using Au/ZnSe as the enhancement substrate that allows a wide spectral range down to 700 cm–1. Au nanoparticles are stably deposited on the surface of a ZnSe prism due to the formation of Au–Se bonds via electroless deposition, and the enhancement factor of the resultant Au/ZnSe substrate is about 2 times larger than that of the commonly used Au/Si substrate. As a demonstration, the Au/ZnSe-based SEIRAS has been applied to obtain abundant structural information in the fingerprint region and quantitative analysis of various biomolecular interactions such as DNA hybridization and immunoreaction without any labeling process.

The surface charge of cells affects cell signaling, cell metabolic processes, adherence to surfaces, and cell proliferation. Our understanding of the role of membrane charges is limited due to the inability to observe changes without interfering, chemically or physically, with the cell or its membrane. Here, we report that a photoelectrochemical imaging system (PEIS) based on label-free ac-photocurrent measurements at indium tin oxide (ITO) coated glass substrates can be used to map the basal surface charge of single live cells under physiological conditions. Cells were cultured on the ITO substrate. Photocurrent images were generated by scanning a focused, modulated laser beam across the back of the ITO coated glass substrate under an applied bias voltage. The photocurrent was shown to be sensitive to the negative surface charge of the substrate facing, basal side of a single living cell-an area not accessible to other electrochemical or electrophysiological imaging techniques. The PEIS was used to monitor the lysis of mesenchymal stem cells.

We propose an in situ and label-free method for detection of biomolecular recognition events by use of a nanochannel-ion channel hybrid device integrated with an electrochemical detector. The aptamer is first immobilized on the outer surface of the nanochannel-ion channel hybrid. Its binding with target thrombin in solution considerably regulates the mass-transfer behavior of the device owing to the varied surface charge density and effective channel size. Via the electrochemical detector, the changed mass-transport property can be monitored in real time, which enables in situ and label-free detection of thrombin-aptamer recognition. The solution pH has a significant influence on detection sensitivity. Under optimal pH conditions, a detection limit as low as 0.22 fM thrombin can be achieved, which is much lower than most reported work. The present nanofluidic device provides a simple, ultrasensitive, and label-free platform for monitoring biomolecular recognition events, which would hold great potential in exploring the functions and reaction mechanisms of biomolecules in living systems.

Structure determination of unexpected products obtained during synthesis of large carbon nanotube sidewall segments with more than 200 carbon atoms represents a challenging task for traditional analytical methods. Herein, we investigate a homologous series of four products having the same number of carbon atoms but slightly different hydrogen numbers ranging from 168 to 162. We demonstrate that the combination of mass spectrometry, ion mobility separation, and collision-induced dissociation (CID) can be used to finally elucidate the complete structures with high certainty. The postulated 1,2-phenyl shift as origin for the side reaction could be proven by changes in the minimum fragment sizes. A combination of CID and ion mobility spectrometry was applied for the first time to prove the cyclic nature of all molecules by the significant size increase upon ring opening. Thereby, also, more compact molecules were discovered in the gas phase with thus far unknown structures. Finally, the potential presence of numerous isomers could be ruled out by drift time measurements and molecular modeling together with theoretical collision cross-section (CCS) calculations. Surprisingly, only one defined structure could be assigned to each macrocycle in the homologous series, most likely as a result of natural selection rules driven by ring strain and steric hindrance. With a decreasing hydrogen content, the macrocycles undergo a stepwise transition from a cylindrical to conical shape. Overall, ion mobility mass spectrometry together with molecular modeling shows great potential to analyze unknown structures, especially in cases where structure determination by X-ray single-crystal analysis is not applicable.

Light-addressable potentiometric sensors (LAPS) are of great interest in bioimaging applications such as the monitoring of concentrations in microfluidic channels or the investigation of metabolic and signaling events in living cells. By measuring the photocurrents at electrolyte-insulator-semiconductor (EIS) and electrolyte-semiconductor structures, LAPS can produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. However, its commercial applications are often restricted by their limited AC photocurrents and resolution of LAPS images. Herein, for the first time, the use of 1D semiconducting oxides in the form of ZnO nanorods for LAPS imaging is explored to solve this issue. A significantly increased AC photocurrent with enhanced image resolution has been achieved based on ZnO nanorods, with a photocurrent of 45.7 ± 0.1 nA at a light intensity of 0.05 mW, a lateral resolution as low as 3.0 μm as demonstrated by images of a PMMA dot on ZnO nanorods and a pH sensitivity of 53 mV/pH. The suitability of the device for bioanalysis and bioimaging was demonstrated by monitoring the degradation of a thin poly(ester amide) film with the enzyme α-chymotrypsin using LAPS. This simple and robust route to fabricate LAPS substrates with excellent performance would provide tremendous opportunities for bioimaging.

Severe atmospheric haze caused by industrial pollution has severely affected human health and led to the increasing incidence of cardiopulmonary diseases, including pneumonia. Conventional methods for diagnosis of pneumonia are complicated and tedious, and current clinical imaging techniques might cause organ injuries to some extent. Therefore, an accurate, fast, and intact imaging method must be developed to diagnose pneumonia in the early stages. In this study, we propose a new two-photon fluorescence probe, named as ASPC, for detection of the activity of the inflammatory biomarker LTA

A novel "wave" signal-smoothing and mercury-removing device has been developed for laser ablation quadrupole and multiple collector ICPMS analysis. With the wave stabilizer that has been developed, the signal stability was improved by a factor of 6.6-10 and no oscillation of the signal intensity was observed at a repetition rate of 1 Hz. Another advantage of the wave stabilizer is that the signal decay time is similar to that without the signal-smoothing device (increased by only 1-2 s for a signal decay of approximately 4 orders of magnitude). Most of the normalized elemental signals (relative to those without the stabilizer) lie within the range of 0.95-1.0 with the wave stabilizer. Thus, the wave stabilizer device does not significantly affect the aerosol transport efficiency. These findings indicate that this device is well-suited for routine optimization of ICPMS, as well as low repetition rate laser ablation analysis, which provides smaller elemental fractionation and better spatial resolution. With the wave signal-smoothing and mercury-removing device, the mercury gas background is reduced by 1 order of magnitude. More importantly, the (202)Hg signal intensity produced in the sulfide standard MASS-1 by laser ablation is reduced from 256 to 0.7 mV by the use of the wave signal-smoothing and mercury-removing device. This result suggests that the mercury is almost completely removed from the sample aerosol particles produced by laser ablation with the operation of the wave mercury-removing device. The wave mercury-removing device that we have designed is very important for Pb isotope ratio and accessory mineral U-Pb dating analysis, where removal of the mercury from the background gas and sample aerosol particles is highly desired. The wave signal-smoothing and mercury-removing device was applied successfully to the determination of the (206)Pb/(204)Pb isotope ratio in samples with low Pb content and/or high Hg content.