Cell Membrane-Camouflaged Biomimetic Magnetic Fluorescent Nanoparticles with Enhanced Stability for High-Performance Lead Drug Discovery.

Biomimetic nanoengineering empowers nanoparticles with enhanced biointerfacial capabilities by directly utilizing cell membranes (CMs) of natural origin. This top-down technique provides a powerful tool for the screening of potentially active compounds in complex matrices. Herein, cartilaginous end plate (CEP) cell membrane biomimetic Nile red (NR)-loaded zeolitic imidazolate frameworks-8 (ZIF-8) modified magnetic graphene oxide (CEP/MGO-ZIF-8-NR) nanocomposites with enhanced stability were accurately prepared by chemical bonding and used as a drug discovery platform for the specific identification and effective extraction of drug leads with anti-intervertebral disc degeneration (IDD) in Yaobitong capsules (YBTCs). The constructed CEP/MGO-ZIF-8-NR exhibited excellent magnetic properties, fluorescence properties, and stability. In addition, drug binding experiments showed that the CEP/MGO-ZIF-8-NR nanocomposites possessed higher adsorption capacity, faster adsorption rate, and superior selectivity compared with uncoated MGO-ZIF-8-NR. Ultimately, four potential bioactive molecules, including ginsenoside Ro, ginsenoside Rg1, astringin, and chikusetsusaponin V methyl ester, were successfully screened and identified in vitro from YBTC. The results of the CCK-8 assay and BrdU ELISA kit showed that the screened compounds promoted CEP cell proliferation in a concentration-dependent manner. Cellular distribution experiments revealed that CEP/MGO-ZIF-8-NR could rapidly escape from lysosomes and into the cytoplasm. And the pharmacological activity of these compounds was further confirmed by real-time cytomorphological imaging of CEP cells by confocal laser scanning microscopy (CLSM). Overall, this surface engineering strategy endows bioaffinity sample pretreatment materials with tremendous versatility, improves drug screening efficiency, and broadens the horizons and methodologies for drug lead discovery.

A novel ratiometric colorimetric sensor for detecting hypochlorite and ascorbic acid based on cascade reaction.

Hypochlorite and ascorbic acid (AA), play an indispensable role in numerous physiological activities. Herein, a ratiometric colorimetric sensing strategy for the determination of hypochlorite and AA was developed via the catalytic oxidation and reduction of 3,3',5,5'-tetramethylbenzidine (TMB). Interestingly, in the presence of Fe3O4-MOF-5(Fe) and hypochlorite, TMB complexes in acidic environments were oxidized to blue oxidized TMB and further diazotized to produce yellow-green diazotized TMB, resulting in the hypochlorite concentration-dependent ratiometric variation for the absorbance at 652 and 450 nm (A450/A652). Moreover, the diazotized TMB was restored to colorless TMB due to the reducibility of AA, and the detection limit of hypochlorite and AA were 0.027 and 0.677 µM, respectively. The ratiometric colorimetric sensing platform offered higher sensitivity and better selectivity because of the specific hypochlorite-induced reaction and the excellent peroxidase-like activity of Fe3O4-MOF-5(Fe). The proposed novel strategy provided the guidance to develop sensors for successive detection of hypochlorite and AA in complicated samples.

Precise Lipidomics Decipher Circulating Ceramide and Sphingomyelin Cycle Associated with the Progression of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a long-term autoimmune condition that causes joint and surrounding tissue inflammation. Lipid mediators are involved in inflammation and deterioration of the joints. Despite attempts to discover effective drug targets to intervene with lipid metabolism in the disease, progress has been limited. In this study, precise lipidomic technology was employed to quantify a broad range of serum ceramides and sphingomyelin (SM) in a large cohort, revealing an association between the accumulation of circulating ceramides and disturbed ceramide/SM cycles during the progression of RA. In our investigation, we discovered that eight ceramides exhibited a positive correlation with the activity of RA, thereby enhancing the accuracy of RA diagnosis, particularly in patients with serum antibody-negative RA. Furthermore, the enzyme SM phosphodiesterase 3 (SMPD3) was found to disrupt the circulating SM cycle and accelerate the progression of RA. The activity of SMPD3 can be inhibited by methotrexate, resulting in decreased metabolic conversion of SM to ceramide. These findings suggest that targeting the SM cycle may provide a new therapeutic option for RA.

Fluorescence Sensor for Zearalenone Detection Based on Oxidized Single-walled Carbon Nanohorns/N-doped Carbon Quantum Dots-aptamer.

Zearalenone (ZEN), a resorcinolactone toxin, which has been a potential threat to agricultural production and human health. In this study, a sample and rapid fluorescence sensor was established for the detection of ZEN, which is based on the fluorescence properties of N-doped carbon dots-aptamer (NCDs-apt) and the quenching ability of oxidized single-walled carbon nanohorns (oxSWCNHs). NCDs synthesized by one-step hydrothermal method were connected with ZEN-aptamer (ZEN-apt), and oxSWCNHs were added to quench the fluorescence of NCDs-apt. Therefore, an oxSWCNHs/NCDs-apt aptasensor based on fluorescence "on-off" for the determination of ZEN in food was formed. Under optimum conditions, the limit of detection (LOD) of this method was 18 ng/mL and the linear range was 20 ~ 100 ng/mL. The possible interfering substances were investigated, and the results showed excellent selectivity. The recoveries were in the range of 99.5%~114.3%, and the relative standard deviations (RSDs) were not more than 6.5%, which demonstrated that this aptasensor was successfully applied for the detection of ZEN in food samples with satisfactory result.

Nitrogen and Sulfur Co-doped Carbon Quantum Dots for Detecting Fe3+, Ascorbic Acid and Alkaline Phosphatase Activities.

A method utilizing nitrogen-doped and sulfur-doped carbon quantum dots (N, S-CQDs) as fluorescent probes for the rapid detection of Fe3+, L-ascorbic acid (AA), and alkaline phosphatase (ALP) was presented. The fluorescence intensity of N, S-CQDs nanoprobes can be rapidly and efficiently quenched by Fe3+ and based on the fluorescence "turn off-on" characteristic of N, S-CQDs nanoprobes, the fluorescence signals of the N, S-CQDs/Fe3+can be recovered after the addition of AA. By coupling a fluorescent nanoprobe to an enzyme and L-ascorbic acid-2-phosphate (AA2P), a green, simple, rapid and effective fluorescent analytical method for the determination of ALP was developed. The prepared N, S-CQDs showed high sensitivity and selectivity to Fe3+, AA and ALP with the detection limit of 0.42 µM, 12.7 nM and 0.017 U·L-1 and their optimal concentration ranges were10-600 µM, 10-200 µM, 0.18-54 U·L-1, respectively. The fluorescence quantum yield of N, S-CQDs (0.2 mg·mL-1) at 393 nm excitation wavelength was 4.41%. Additionally, the fluorescent nanoprobes have been employed to successfully measure ALP in serum samples. It is expected that the established method may offer a new approach for biomolecular detection in clinical diagnosis and pharmaceutical analysis.

Rapid, sensitive, and high-throughput quantification of broad serological ceramides by using isotope dilution liquid chromatography-negative ion electrospray tandem mass spectrometry.

Ceramides are important intermediates in the metabolism of sphingolipids. High-throughput liquid chromatography-mass spectrometry has been used extensively for monitoring the levels of serological ceramides, but is still limited by inadequate coverage or lack of sensitivity. Herein, a rapid, sensitive, and high-throughput isotope dilution liquid chromatography-negative ion electrospray tandem mass spectrometry (IDLC-nESI-MS/MS) method was developed and verified for accurate quantification of 41 ceramides, involving ceramides with C16-20 sphingosine, dihydro-ceramide, and dehydro-ceramide. This method was validated with excellent linearity (R2 > 0.99) and good recovery in the range of 90-110%. Intra- and inter-day imprecision were below 5.57% and 7.83% respectively. The improved high-throughput quantitative method developed in this study may aid in the accurate characterization of ceramides for understanding ceramide biology and application in disease diagnosis.

Integrated gas chromatography-mass spectrometry and ultra-high-performance liquid chromatography-mass spectrometry renal metabolomics and lipidomics deciphered the metabolic regulation mechanism of Gushudan on kidney-yang-deficiency-syndrome rats.

Kidney-yang-deficiency-syndrome is a neuroendocrine disease caused by the dysfunction of the adrenal-pituitary-target gland axis. Gushudan is a traditional Chinese medicine prescription with the functions of tonifying the kidney and strengthening bone, and its bone-strengthening effect has been confirmed by previous anti-osteoporosis research. However, its kidney-tonifying mechanism has not been clear so far. In this study, renal metabolomics and lipidomics based on gas chromatography-mass spectrometry and ultra-high-performance liquid chromatography-high resolution mass spectrometry were integrated to find the metabolic disorders in kidney-yang-deficiency-syndrome rats. Protein precipitation and liquid-liquid extraction were used to extract metabolome and lipidome from the kidney. Gushudan regulated abnormal levels of amino acids, lipids, purines, and carbohydrates, such as L-arginine, hypoxanine, stearic acid, and phosphatidylethanolamine (P-18:1/20:4), which had effects on many metabolic pathways, such as glycerophospholipid metabolism, sphingolipid metabolism, glycine, serine and threonine metabolism and purine metabolism, and so forth. By integrating metabolomics and lipidomics, this study comprehensively revealed the abnormal metabolic activities of amino acids, lipids, and nucleotides in kidney-yang-deficiency-syndrome, and the metabolic regulation mechanism of Gushudan in preventing kidney-yang-deficiency-syndrome, as well as the improvement of Gushudan in maintaining renal cell structure, mitochondrial function, and energy supply, which also provided some new evidence and connotation for "kidney-bone" axis.

An integrated fecal metabolomic based on 1 H-NMR and UPLC-QTOF-MS revealed the preventive mechanism of Gushudan on glucocorticoid-induced osteoporotic rats.

Gushudan (GSD) has the effect of strengthening bones and nourishing kidneys. However, its specific intervention mechanism still remains unclear. In this study, to investigate the pathogenesis of glucocorticoid-induced osteoporosis (GIOP) and the preventive mechanism of GSD on GIOP, fecal metabolomics based on 1 H-NMR and ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry method was established. The changes in endogenous metabolites and the relevant metabolic pathways in the control group, model group, and GSD treatment group were investigated via multivariate statistical analysis. As a result, a total of 39 differential metabolites were identified. Of these, 22 metabolites, such as L-methionine, guanine, and sphingosine, were newly discovered as differential metabolites of GIOP. Amino acid metabolism, energy metabolism, intestinal flora metabolism, and lipid metabolism were significantly changed in the fecal profiles of GIOP rats, and GSD could play an anti-osteoporosis role by regulating these metabolic pathways. Finally, compared with our previous study of the GSD to prevent kidney yang deficiency syndrome, this study suggested that there were some identical differential metabolites and metabolic pathways. It showed that there was some correlation among the metabolic profiles of the intestine, kidney, and bone in GIOP rats. Therefore, this study offered new insights into the in-depth understanding of the pathogenesis of GIOP and the intervention mechanism of GSD.

Vortex-assisted dispersive liquid-liquid microextraction based on the hydrophobic deep eutectic solvent-based ferrofluid for extraction and detection of myclobutanil.

A vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME) procedure using hydrophobic deep eutectic solvent-based ferrofluid (HDES-FF) as an extractant was established. The developed sample preparation method coupled with high-performance liquid chromatography-diode array detector (HPLC-DAD) was applied to the pretreatment and determination of myclobutanil (MYC) in fruit juice. Hydrophobic deep eutectic solvent, synthesized by n-decanoic acid and DL-menthol, was as a carrier and combined with magnetic nanoparticles (Fe3O4@OA) to form HDES-FF as an extractant with high extraction capacity. The synthesized materials were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Parameters affecting extraction efficiency were optimized using single-factor experiments and Box-Behnken design via response surface methodology (BBD-RSM). Parallel tests were performed three times under the optimal conditions predicted by the model, yielding an actual mean recovery of 94.77% with RSD of 2.7% (n = 3) and an enrichment factor of 41.8 ± 0.98 (mean value ± SD, n = 3). Under the optimal conditions, the linear range was 1.0-100.0 µg·mL-1; the limit of detection (LOD) and limit of quantification (LOQ) were 0.25 and 0.80 µg·mL-1, respectively. The average spiked recoveries in the samples ranged from 98.2 to 100.5% with intra-day relative standard deviations (RSDs) of 1.2-3.5% (n = 3) and inter-day RSDs of 1.1-3.8% (n = 3). Finally, the method was successfully applied to the determination of MYC antimicrobial agent in different fruit juice samples. The proposed HDES-FF-VA-DLLME/HPLC-DAD method was verified to widely apply to the extraction of triazole fungicides.

Colorimetric determination of cholesterol based on the peroxidase-like activity of Cu-Salt-Fe nanozyme with multiple active sites.

A strategy to enhance the peroxidase-like activity of the hemin composite is presented. The Cu-Salt-Fe with enhanced activity was synthesized by one-step heat treatment and applied to the colorimetric determination of free cholesterol in human serum. Phosphate can act in complexing Cu2+ to form a carrier Cu-Floc with a large specific surface area. The coordination effect of Cu-Floc with hemin was used to disperse and load hemin to form Cu-Floc-Hemin from which Cu-Salt-Fe was prepared. The Cu-Salt-Fe exhibits a synergistic catalytic effect of Cu-Salt, Fe2+, Fe3+, or Fe-Nx active sites in amplification of H2O2 oxidation. As expected, Cu-Salt-Fe triggered H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), resulting in H2O2-dependent absorbance changes at 652 nm. A cholesterol oxidase (ChOx)/Cu-Salt-Fe-TMB colorimetric sensing system exhibited excellent cholesterol determination performance in the range 5-1200 µM with a detection limit of 2.73 µM. Cholesterol recoveries from the three-level spiked serum ranged from 92.2 to 98.9% (RSD ≤ 5.4). This colorimetric sensing system not only provided a strategy for the determination of endogenous substances with H2O2 as an intermediate, but also provided a new design idea (carrier selection, activity enhancement method) for the development of other artificial enzymes with the same catalytic core.

pH-responsive magnetic graphene oxide composite as an adsorbent with high affinity for rapid capture of nucleosides.

A novel pH-responsive magnetic graphene oxide composite (MGO@PEI-BA) is proposed for the first time as an adsorbent for the rapid capture and detection of nucleosides (cytidine, uridine, guanosine, and adenosine). The morphology, structure, and magnetic properties of the composite were evaluated using various characterization techniques. The results indicated that the composite was successfully fabricated. A series of parameters that affect extraction and elution were optimized through one-factor-at-a-time and Box-Behnken design of response surface methodology (BBD-RSM). The unique layered structures and easily accessible active sites of the composite facilitated molecular transport, resulting in instantaneous equilibrium of nucleosides adsorption within 5 min. Based on this study, a magnetic dispersive micro-solid-phase extraction (MD-µ-SPE) method assisted by the MGO@PEI-BA was developed in combination with UHPLC-UV analysis for the determination of nucleosides in rat urine. Under the optimum conditions, a wide linear range (10-2000 ng mL-1), good linearity (r > 0.99), low detection limits (1-3 ng mL-1), low relative standard deviations (RSDs ≤ 3.9%), and satisfactory recoveries (82.7-96.3%) were achieved. These results demonstrate that the MGO@PEI-BA is an excellent adsorbent for extracting nucleosides from biological samples.

A Bifunctional Fluorescence Probe Based on AIE-ICT Strategy for Visual Detection of Cu2+/Co2+ in Complex Matrix.

A novel fluorescence chemical sensor-based probe 1-{[(E)-(2-aminophenyl)azanylidene]methyl}naphthalen-2-ol (AMN) was designed and synthesized, which performed a "naked eye" detection ability toward Cu2+ and Co2+ based on aggregation-induced emission (AIE) fluorescence strategy. It has sensitive detection ability for Cu2+ and Co2+. In addition, the color changed from yellow-green to orange under the sunlight, realizing the rapid identification of Cu2+/Co2+, which has the potential of on-site visual detection under the "naked eye". Moreover, different "on" and "off" fluorescence expressions were exhibited under excessive glutathione (GSH) in AMN-Cu2+ and AMN-Co2+ systems, which could be employed to distinguish Cu2+ from Co2+. The detection limits for Cu2+ and Co2+ were measured to be 8.29 × 10-8 M and 9.13 × 10-8 M, respectively. The binding mode of AMN was calculated to be 2:1 by Jobs' plot method analysis. Ultimately, the new fluorescence sensor was applied to detect Cu2+ and Co2+ in real samples (tap water, river water, and yellow croaker), and the results were satisfying. Therefore, this high-efficiency bifunctional chemical sensor platform based on "on-off" fluorescence detection will provide significant guidance for the advance development of single-molecule sensors for multi-ion detection.

1H NMR serum metabolomics and its endogenous network pharmacological analysis of Gushudan on kidney-yang-deficiency-syndrome rats.

The pharmacodynamics, 1H NMR metabolomics and endogenous network pharmacology strategy approaches were integrated to investigate the preventive mechanism of Gushudan (GSD) on kidney-yang-deficiency-syndrome (KYDS) rats in this study. Firstly, the KYDS rat model was achieved by hydrocortisone induction, and the efficacy of GSD on KYDS model rats was assessed by the pharmacodynamic indicators. Next, the comprehensive untargeted serum metabolic profile of rats was obtained in 1H NMR metabolomics study, 29 potential biomarkers closely associated with KYDS were identified, which were mainly involved in carbohydrate metabolism, amino acid metabolism and intestinal flora metabolism. In addition, the potential biomarkers-targets-pathways-disease metabolic network was further investigated for deeper understanding the preventive effects of GSD on KYDS rats and its mechanism, which was further obtained for the important targets related to biomarkers and diseases such as NOS3, PTGS2 and CXCL8, and important metabolic pathways such as glyoxylate and dicarboxylate metabolism, arginine and proline metabolism, and microbial metabolism in diverse environments. Finally, compared with our previous anti-osteoporosis study of GSD, it suggested that some similar metabolic pathways, which would provide some scientific reference of the existence of the kidney-bone axis under the traditional Chinese medicine (TCM) theory of "kidney dominates bone".

Integrative serum metabolomic analysis for preventive effects of Yaobitong capsule in adjuvant-induced rheumatoid arthritis rat based on RP/HILIC-UHPLC-Q-TOF MS.

Yaobitong capsule (YBTC) has been used for the prevention and treatment of inflammation-related lumbago and leg pain. However, its intervention mechanism still remains unclear. This study was aimed to evaluate the control efficiency of YBTC on adjuvant-induced rheumatoid arthritis (RA) rats by metabonomic method and to explore its possible anti-arthritis mechanism. Taking into account the complexity of endogenous metabolites in serum samples, an integrated metabolomics method based on RP/HILIC-UHPLC-Q-TOF MS was developed, to overcome the limitations of a single chromatographic in this study. The results showed that 32 potential biomarkers of arthritis were identified, primarily related to amino acid metabolism, glucose metabolism, lipid metabolism and nucleotide metabolism. Further receiver operating characteristic analysis revealed that the area under the curve of two down-regulated metabolites (3-Hydroxy-hexadecanoic acid, 2-Oxoarginine) and one up-regulated metabolite (l-Glutamic acid) among 32 biomarkers were 0.906, 0.969 and 1.000, respectively, indicating that high predictive ability of this method for RA. In this study, an integrated serum metabolomics method based on high-resolution mass spectrometry was successfully established for the first time to study the intervention mechanism of YBTC in RA, providing evidence regarding the clinical application of YBTC and a new insight for the prevention of RA in the future.

A liquid chromatography-mass spectrometry untargeted urinary metabonomics combined with quantitative analysis of seven amino acids biomarkers on yaobitong capsule in the intervention of rheumatoid arthritis rats.

Yaobitong capsule is a compound preparation of traditional Chinese medicine that has been widely applied in disease treatment. To insight into the therapeutic effects of the yaobitong capsule on rheumatoid arthritis and its mechanisms, a liquid chromatography-mass spectrometry untargeted urine metabolomics method was established and validated, combined with the quantitative analysis of seven potential amino acid biomarkers in rat urine. The results showed that 35 potential biomarkers were found in untargeted metabonomics, which was related to amino acid metabolism, lipid metabolism, energy metabolism, and purine metabolism. Moreover, seven amino acid biomarkers, including proline, methionine, glutamic acid, histidine, lysine, cysteine, and glutamine, were further separated and quantified in multiple-reaction monitoring with a positive ionization mode. Then the linearity, standard curves, accuracy, precision, limit of quantitation, recovery, stability, carryover, and matrix effect of the quantitative method were examined. Finally, the validated method was successfully applied to investigate the urine samples of the control group, adjuvant-induced rheumatoid arthritis model group, yaobitong capsule-treatment group, and positive control group in rats. The contents of seven amino acids in different groups showed significant differences. Consequently, our findings revealed that the yaobitong capsule exerted therapeutic effects on rheumatoid arthritis rats by maintaining amino acid homeostasis.

Mechanisms exploration of terrestrosin D on pulmonary fibrosis based on plasma metabolomics and network pharmacology.

Terrestrosin D (TED) is the active ingredient of Tribulus terrestris L., which is used in traditional Chinese medicine (TCM) formulations and has a wide range of pharmacological activities. A previous study showed that TED alleviated bleomycin (BLM)-induced pulmonary fibrosis (PF) in mice. However, the mechanisms underlying the therapeutic effect of TED are still unclear and need further investigation. In this study, we evaluated the effect of TED in a mice of BLM-induced PF in terms of histopathological and biochemical indices. UHPLC-MS-based plasma metabolomics combined with network pharmacology was used to explore the pathological basis of PF and the mechanism of action of TED. Histological and biochemical analyses showed that TED mitigated inflammatory injury in the lungs, especially at the dosage of 20 mg/kg. Furthermore, BLM changed the plasma metabolite profile in the mice, which was reversed by TED via regulation of amino acid and lipid metabolism. Subsequently, a biomarkers-targets-disease network was constructed, and tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß1 were identified as the putative therapeutic targets of TED. Both factors were quantitatively analyzed using enzyme-linked immunosorbent assay (ELISA). Taken together, the combination of UHPLC-MS-based metabolomics and network pharmacology can unveil the mechanisms of diseases and drug action.

CuCo2S4 nanozyme-based stimulus-responsive hydrogel kit for rapid point-of-care testing of uric acid.

An efficient analysis platform composed of nanozyme-based hydrogel kit and smartphone was constructed for on-site detection of uric acid (UA) in a rapid and realiable manner. CuCo2S4 nanoparticles (CuCo2S4 NPs) as a peroxidase mimic were successfully prepared and the peroxidase-like activity and catalytic mechanism were studied in detail. The hydrogen peroxide (H2O2) stimulus-responsive nanozyme-based hydrogel kit was manufactured by integrating agarose, CuCo2S4 NPs, and 3,3',5,5'-tetramethylbenzidine (TMB) into the cap of centrifuge tube. H2O2 generated via UA oxidation acts as stimulus signal, which triggers the oxidation of TMB to form blue product (oxTMB) under the catalysis of CuCo2S4 NPs, resulting in the color response of the constructed kit. The color image of the kit was captured by a smartphone built-in camera and converted into color intensity using ImageJ software, thus achieving the quantitative determination of UA. The portable kit possesses high selectivity and was used to monitor UA in human serum with satisfactory results (recovery was in the range 95.8-107.3% and RSD was not greater than 4.6%). The established sensing platform is convenient and reliable, which provides a new strategy for point-of-care testing of UA and has a broad prospect in the fields of chemical sensing and biomedical.

A Hydrothermal Method to Generate Carbon Quantum Dots from Waste Bones and Their Detection of Laundry Powder.

Surfactants are one of the major pollutants in laundry powder, which have an impact on the environment and human health. Carbon quantum dots (CQDs) are spherical zero-dimensional fluorescent nanoparticles with great potential for fluorescent probing, electrochemical biosensing and ion sensing. Herein, a bottom-up approach was developed for the synthesis of CQDs from biomass to detect laundry detergent and laundry powder. Waste chicken bones were used as carbon precursors after being dried, crushed and reacted with pure water at 180 °C for 4 h to generate CQDs, which exhibited a monodisperse quasi-spherical structure with an average particle size of 3.2 ± 0.2 nm. Functional groups, including -OH, C=O, C=C and C-O, were identified on the surface of the prepared CQDs. The optimal fluorescence excitation wavelength of the yellow-brown CQDs was 380 nm, with a corresponding emission peak at 465 nm. CQDs did not significantly increase cell death in multiple cell lines at concentrations of 200 µg·mL-1. Fluorescence enhancement of CQDs was observed after addition of sodium dodecyl benzene sulphonate, a major anionic surfactant in laundry powder. A linear relationship between fluorescence enhancement CQDs and the concentration of laundry powder was established. Thus, a hydrothermal method was developed to generate CQDs from waste biomass that may be used as a fluorescent probe to detect laundry powder.

Nitrogen-Doped Carbon Dot and CdTe Quantum Dot Dual-Color Multifunctional Fluorescent Sensing Platform: Sensing Behavior and Glucose and pH Detection.

A novel fluorescent probe based on a nitrogen-doped carbon dot (N-CD) and CdTe quantum dot (CdTe QD) platform has been constructed for H2O2/glucose detection and pH sensing. In this work, H2O2-tolerant blue fluorescence N-CDs were added to the H2O2-mediated yellow fluorescence quenching of CdTe QDs to construct a dual-color ratiometric fluorescent H2O2 probe. H2O2-induced passivated group detachment and action on deep nanocrystals promoted CdTe QD fluorescence quenching. Meanwhile, the addition of the blue fluorescent background of N-CDs sharply reflected the color change in CdTe QDs. Under the optimized experimental conditions, the platform was effectively applied to the detection of H2O2 produced by the enzymatic reaction of glucose, showing high sensitivity (limit of detection 7.86 µM) and wide linear range (26-900 µM) for glucose detection. The pH-sensing behavior of CdTe QDs and N-CDs was attributed to the displacement of a weak acid (3-mercaptopropionic acid) by a strong acid (HCl) and the acid titration process of two coexisting bases (N-CDs and NH3·H2O), respectively. The loss of passivation and doping effects led to a decrease in the fluorescence intensity of CdTe QDs and N-CDs. Moreover, utilizing the ability of bimaterial system fluorescence to pH sensing, a semiquantitative pH detection based on the linear response was developed. The pH range was analyzed by three kinds of N-CD (Fex = 440 nm) and CdTe QD (Fex = 548 nm) typical emission spectral shapes. In addition, the recovery results showed that the bimaterial system was proved to be appropriate for the assay of glucose in spiked serum samples.

Integrative metabolic profile of myelodysplastic syndrome based on UHPLC-MS.

Myelodysplastic syndrome (MDS) is a neoplastic disease originating from hematopoietic stem cells. Currently, hematopoietic stem cell transplantation (HSCT) is the most effective cure, although lenalidomide, azacytidine, and decitabine have been applied to relieve symptoms of MDS. The purpose of this study was to evaluate the changes in endogenous metabolites by applying a UHPLC-MS (ultra-high-performance liquid chromatography-MS) metabolomics approach and to investigate metabolic pathways related to MDS. An untargeted metabolomics approach based on UHPLC-MS in combination with multivariate data analysis, including partial least squares discrimination analysis and orthogonal partial least squares discriminant analysis, was established to investigate potential biomarkers in the plasma of MDS patients. As a result, 29 biomarkers were identified to distinguish between MDS patients, HSCT patients, and healthy controls, which were mainly related to inflammation regulation, amino acid metabolism, fatty acid metabolism, and energy metabolism. To our knowledge, this is the first time where plasma metabolomics was combined with HSCT to study the pathogenesis and therapeutic target of MDS. The identification of biomarkers and analysis of metabolic pathways could offer the possibility of discovering new therapeutic targets for MDS in the future.