Developing an off-on fluorescence sensor based on red copper nanoclusters wrapped by sulfhydryl and polymer double ligands for sensitive detection of N-acetyl-L-cysteine.

N-acetyl-L-cysteine (NAC) as a class of thiols is commonly used in the treatment of lung diseases, detoxification and prevention of liver damage. In this paper, 4-mercaptobenzoic acid (4-MBA) coated and polyvinylpyrrolidone (PVP) attached copper nanoclusters (4-MBA@PVP-CuNCs) were successfully synthesized using a simple one-pot method with an absolute quantum yield of 10.98 %, and its synthetic conditions (like effects of single/double ligands and temperature) were studied intensively. Then Hg2+ could quench the fluorescence of the 4-MBA@PVP-CuNCs and its fluorescence was restored with the addition of NAC. Based on the above principles, an off-on switching system was established to detect NAC. That is, the 4-MBA@PVP-CuNCs-Hg probe was prepared by adding Hg2+ to switch off the fluorescence of the CuNCs by static quenching, and then NAC was added to switch on the fluorescence of the probe based on the chelation of NAC and Hg2+. Moreover, the effects of metal ion types and mercury ion doses for the probe construction were also further discussed. The method showed excellent linearity in the range of 0.05-1.25 µM and low detection limit of 16 nM. Meanwhile, good recoveries in real urine, tablets and pellets were observed, which proved the reliability of the method and provided a convenient, fast and sensitive method for NAC detection.

Glutathione Modified silicon-doped Carbon Quantum dots as a Sensitive Fluorescent Probe for ClO- Detection.

A selective and sensitive fluorescence method for hypochlorite (ClO-) was designed using glutathione (GSH) modified silicon-doped carbon quantum dots (GSH@Si-CDs). Then a dual emission ratio fluorescence probe (RF-probe) was obtained based on carbodiimide-activated coupling reaction between GSH and Si-CDs. i.e., when the excitation wavelength was kept at 360 nm, the GSH@Si-CDs exhibited strong blue and weak yellow fluorescence at 430 and 580 nm. Meanwhile, the fluorescence of GSH@Si-CDs could be selectively quenched at 430 nm and enhanced at 580 nm in the presence of ClO-, and corresponding limit of detection (LOD) and linear range were measured to be 0.35 µM and 1.0-33.3 µM. The sensing mechanism of the system was also investigated in detail. Moreover, the RF-probe with good accuracy was successfully employed to monitor ClO- in real samples with satisfactory results compared to the standard iodometric method.

A Ratio Fluorescence Method Based on Dual Emissive Copper Nanoclusters for the Detection of Vanillin.

In this study, a novel double-emission fluorescence probe at 340 and 400 nm was synthesized by one-pot method using phenylalanine (Phe) and ascorbic acid (AA) as stabilizing and reducing agents. It was found that the fluorescence intensity of the probe at 400 nm could be controlled by controlling the temperature within a certain range, and the ratio of double-emission fluorescence probe could be further regulated. Under the optimal conditions, the fluorescence intensity at 340 nm decreased significantly, while it only showed a slight decrease at 400 nm, which constituted the ratio fluorescence probe. The synthesized fluorescence probe showed good linearity in the range of 0.2-32 µM, and its detection limit was 63.4 nM. Moreover, the method was successfully employed to determine VA in vanilla drink and perfumes, and corresponding results were consistent with those of HPLC.

Sensitive Detections of Sodium Dichloroisocyanurate and Rosmarinic Acid by Polyvinylpyrrolidone Coated Copper Nanoclusters.

In this article, the water-soluble blue-light-emitting copper nanoclusters (CuNCs) were prepared by polyvinylpyrrolidone (PVP) and ascorbic acid as templating and reducing agents, respectively. The optimization of synthesis conditions of PVP-CuNCs were studied and analyzed. And the quantum yield of the PVP-CuNCs was calculated to be 14.97%. It had good specificity and exceptionally sensitive detection for sodium dichloroisocyanurate (DCCNa)/rosmarinic acid (RA), with a linear response range of 0.030-2.400/0.030-0.900 µM and corresponding LOD value of 10.766/8.985 nM. Moreover, the fluorescent reaction mechanisms of the PVP-CuNCs-DCCNa and PVP-CuNCs-DCCNa-RA systems were discussed, and the sensing probe could be effectively used for the assays of DCCNa and RA in genuine samples, whose results were acceptable.

Silicon Doped Carbon Dots as an New Ratiometric Fluorescence Probe for Proanthocyanidins Assay Based on the Redox Reaction Between Cr(VI) and Proanthocyanidins.

In the study, silicon doped carbon quantum dots (Si-CQDs) was prepared by one-pot hydrothermal method with (3-aminopropyl) triethoxysilane (APTES) and o-phenylenediamine (OPD) as raw materials. Then a new ratiometric fluorescent probe (RF-probe) was successfully established for sensitively and selectively monitoring proanthocyanidins (PAs) with a linear range of 10-500 nM and limit of detection (LOD) of 5.6 nM. that is, the fluorescence (FL) intensity of Si-CQDs at 570 nm was used as the built-in reference, while dopamine (DA) reacting with 4-hexylresorcinol (4-HR) could produce a new fluorescent substance (named as azamonardine, AZMON), and its FL intensity at 480 nm was reduced because Cr(VI) could oxidize DA to generate quinone without fluorescence. In the presence of PAs, Cr(VI) was reduced to Cr(III), which caused that the amount of DA reacting with 4-HR was increased, thus the FL intensity of AZMON was recovered. Furthermore, the RF-probe was successfully used for the determination of PAs in black goji berry from two different areas and PAs capsule with satisfactory results compared to the standard HPLC method.

Impact of perioperative blood transfusion on long-term survival in patients with different stages of perihilar cholangiocarcinoma treated with curative resection: A multicentre propensity score matching study.

Background & aim: The association of perioperative blood transfusion (PBT) with long-term survival in perihilar cholangiocarcinoma (pCCA) patients after surgical resection with curative intent is controversial and may differ among different stages of the disease. This study aimed to investigate the impact of PBT on long-term survival of patients with different stages of pCCA. Methods: Consecutive pCCA patients from three hospitals treated with curative resection from 2012 to 2019 were enrolled and divided into the PBT and non-PBT groups. Propensity score matching (PSM) was used to balance differences in baseline characteristics between the PBT and non-PBT groups. Kaplan-Meier curves and log-rank test were used to compare overall survival (OS) and recurrence-free survival (RFS) between patients with all tumor stages, early stage (8th AJCC stage I), and non-early stage (8th AJCC stage II-IV) pCCA in the PBT and non-PBT groups. Cox regression analysis was used to determine the impact of PBT on OS and RFS of these patients. Results: 302 pCCA patients treated with curative resection were enrolled into this study. Before PSM, 68 patients (22 patients in the PBT group) were in the early stage and 234 patients (108 patients in the PBT group) were in the non-early stage. Patients with early stage pCCA in the PBT group had significantly lower OS and RFS rates than those in the non-PBT group. However, there were with no significant differences between the 2 groups with all tumor stages and non-early stage pCCA. After PSM, there were 18 matched pairs of patients with early stage and 72 matched pairs of patients with non-early stage. Similar results were obtained in the pre- and post-PSM cohorts: patients with early stage pCCA in the PBT group showed significantly lower OS and RFS rates than those in the non-PBT group, but there were no significant differences between the 2 groups for patients with all tumor stages and non-early stage pCCA. Cox regression analysis demonstrated that PBT was independently associated with worse OS and RFS for patients with early stage pCCA. Conclusions: PBT had a negative impact on long-term survival in patients with early stage pCCA after curative resection, but not in patients with non-early stage pCCA.

Activation of cGAS-STING Signal to Inhibit the Proliferation of Bladder Cancer: The Immune Effect of Cisplatin.

Cisplatin is commonly used in neoadjuvant, adjuvant, and systemic therapy for advanced bladder cancer, but its immune-related mechanism is still unclear. Exploration of the immune effects of cisplatin in bladder cancer would complement the comprehensive mechanism of cisplatin and provide the basis for combination therapy of cisplatin and immunotherapy in bladder cancer. We confirmed the immune effects of cisplatin on T24 and TCCSUP bladder cancer cell lines in vitro and explored the important function of these immune effects in the bladder cancer microenvironment in a mice tumor model. We found cisplatin induced immune response in bladder cancer by RNA sequencing and validated that cGAS-STING signal was deeply involved in this response. Cisplatin induced cGAS-STING signal inhibited the proliferation of bladder cancer and increased the infiltration percentages of CD8+ T cells and dendritic cells in a transplantation mice tumor model. Accumulation of dsDNA and the release of chromatin bound cGAS are important to activate downstream STING. Our findings indicated a cisplatin-related immune effect in bladder cancer, and cisplatin combined with immunotherapy might have a synergistic effect for bladder cancer therapy.

Ratiometric detection of doxycycline in pharmaceutical based on dual ligands-enhanced copper nanoclusters.

A water-soluble, stable, simple and dual ligands (bovine serum albumin and L-histidine)-enhanced copper nanoclusters (BSA-CuNCs@L-His) was synthesized by one-step wet chemical method. Interestingly, the introduction of L-His ligand could improve evidently the quantum yields (QYs, 3.47%) and stability of BSA-CuNCs due to forming the stronger interaction of L-His and Cu and producing bigger diameter CuNCs by coordination-induced aggregation. Thus, a new ratiometric fluorescent probe (RF-probe) was successfully exploited for sensitively and selectively mensurating doxycycline (DOX) because DOX could simultaneously regulate the fluorescence (FL) intensities of BSA-CuNCs@L-His at 410 and 520 nm. The FL quenching of BSA-CuNCs@L-His at 410 nm by DOX was mainly originated from the static quenching process, while DOX could bind to Trp-212 in BSA from the skeleton of BSA-CuNCs@L-His by electrostatic interaction causing the appearance of new emission peak at 520 nm. The content of DOX was monitored by the RF-probe with a linear range of 0.05-14.0 µM and a LOD (limit of detection) and LOQ (limit of quantification) of 6.4 and 21.3 nM (at 3σ/slope and 10σ/slope). Moreover, compared to the standard HPLC method, the proposed RF-probe was extended to the detection of DOX in doxycycline hydrochloride (DOXH) tablets, DOXH injections and DOXH capsules with satisfactory results.

A ratiometric fluorescent sensing of proanthocyanidins by MnO2 nanosheets simultaneously tuning the photoluminescence of Au/AgNCs and thiamine.

By simultaneously regulating the photoluminescence of alloy Au/Ag nanoclusters (NCs) and thiamine (VB1) through MnO2 nanosheets (MnO2 NS), a novel ratiometric fluorescent probe (RF-probe) was established for sensitively and selectively monitoring proanthocyanidins (PAs). The introduction of Ag (I) ions could enhance significantly the quantum yields (QYs, 11.1%) of AuNCs based on the synthetic method of UVI (UV irradiation) combined with MWH (microwave heating). MnO2 NS could quench the fluorescence (FL) of Au/AgNCs mainly coming from Förster resonance energy transfer (FRET), while it could act as a nanozyme catalyst for directly catalyzing the oxidation of VB1 to produce highly fluorescent oxVB1. In the presence of PAs, MnO2 was reduced to Mn2+, which caused that its quenching capacity and oxidase-like activity were vanished, thus the FL of oxVB1 and Au/AgNCs was reduced and recovered. The concentration of PAs could be monitored by the RF-probe with a linear range of 0.27-22.4 µmol L-1 and corresponding limit of detection (LOD) and limit of quantification (LOQ) were calculated to be 75.9 and 250.5 nmol L-1. Furthermore, the RF-probe was successfully used for the determination of PAs in mineral water, PAs additive and PAs capsule with satisfactory results compared to the standard HPLC method.

Alliance between doping Ag and dual ligands-enhanced fluorescent gold nanoclusters for the assays of vitamin B12 and chlortetracycline hydrochloride.

A stable, water-soluble, heightened quantum yields (QYs) Au nanoclusters by the alliance between doping Ag and dual ligands (thiosalicylic acid and bovine serum albumin) (TSA/BSA-Au/AgNCs) was prepared using one-step wet chemical synthesis. The effect of different types of aromatic thiols and the molar ratio of Au-Ag on the photo-luminescence performance of AuNCs was discussed in detail. The alloy NCs is shown to be viable fluorescent method for vitamin B12 (VB12) and chlortetracycline hydrochloride (CCH) assays, and become an excellent temperature sensor in the range of 10-50 °C. The fluorescence (FL) of TSA/BSA-Au/AgNCs was quenched with the addition of VB12 or CCH coming from Förster resonance energy transfer (FRET) combined with inner filter effect (IFE). The method can detect VB12/CCH by fluorometry with a linear response in the range of 0.33-60.0/0.33-60.0 µmol·L-1 and a 71.0/64.0 nmol·L-1 detection limit (at 3σ/slope). Furthermore, the proposed method was extended to the assays of VB12 in mineral water or tablets and CCH in veterinary drug or ointment with satisfactory results.

Conjugated Cationic Pp-x Formed on g-C3N4 for Photocatalyzed Water Splitting.

Polycationic Pp-x@g-C3N4 composite was synthesized through an in situ polymerization process of N-alkylpyridinium acetylenic alcohol bromide (p-x) above the surface of g-C3N4. The structure of p-0 and the Pp-x@g-C3N4 properties were checked by modern technologies. Photocatalytic tests of Pp-x@g-C3N4 in water splitting unveiled much better Pp-x@g-C3N4 hydrogen evolution activities by comparison with both g-C3N4 and Pp-0. The hydrogen production by Pp-0@g-C3N4 was 1654.5 µmol h-1 g-1, which is ∼26- and 22-fold greater in relation to what g-C3N4 and Pp-0 produced (62.7 and 75.0 µmol h-1 g-1, respectively), suggesting strong bilateral and synergistic interactions of g-C3N4 with Pp-0. Although the lengthening methylene chain in the polymers weakened the hydrogen generation ability of Pp-x@g-C3N4, the conjugated double bonds, solubilization, and dispersion of Pp-x polycationic surfactants made Pp-x@g-C3N4 superior to g-C3N4 in water splitting. Due to the readily available raw materials, a simple way of preparation (starting chemicals to p-0 to Pp-0@g-C3N4), high photocatalysis efficiency, light irritation stability, recyclable ability, and low toxicity, Pp-0@g-C3N4 is a good candidate for water splitting.

Porous ZIF-8@polyacrylonitrile composite beads for iodine capture.

The safe and effective capture and storage of iodine from nuclear waste is of great significance in industry. This article reports the preparation of a series of millimeter-sized ZIF-8@polyacrylonitrile composite beads with high specific surface area and porosity by the phase inversion method for iodine capture. The composite beads showed a higher capture capacity (4150 mg g-1) under excess iodine vapor. The amount of iodine adsorbed in the organic solution is also as high as 643 mg g-1, and the adsorption conforms to the Freundlich isotherm and the pseudo-second-order kinetic model. Moreover, composite beads also exhibit higher thermal stability (310 °C). Therefore, ZIF-8@polyacrylonitrile composite beads show great potential as a material for capturing and temporarily storing radioactive iodine.

Poly(sodium-p-styrenesulfonate)-enhanced fluorescent silver nanoclusters for the assay of two food flavors and silicic acid.

A water-soluble, long-term stable, poly(sodium-p-styrenesulfonate)-enhanced and d-penicillamine stabilized argentum nanoclusters (PSS-DPA-AgNCs) was synthesized by a one-step ultraviolet radiation combined with microwave heating method. The effects of different types of polyelectrolytes and energy suppliers on the AgNCs photo-luminescence performance were investigated in detail. The prepared AgNCs are exhibited to be viable fluorescent method for 2-Mercapto-3-butanol (2-M-3-B), 3-Mercapto-2-butanone (3-M-2-B) and silicate (SiO32-) determinations. The fluorescence (FL) of PSS-DPA-AgNCs is quenched with the addition of 2-M-3-B/3-M-2-B/SiO32- mainly originating from a static quenching process. The method can monitor 2-M-3-B/3-M-2-B by fluorometry with a linear response in the range of 0.33-90.0/0.33-80.0 µM and a 74/250 nM detection limit (at 3σ/slope). For the SiO32- assay, corresponding data are 3.33-100.0 µM and 278 nM. Moreover, the proposed method was successfully used for the assays of two food flavors in the steamed bread and soda drinks, and silicate in the mineral water samples respectively.

Fluorometric assay of iron(II) lactate hydrate and ammonium ferric citrate in food and medicine based on poly(sodium-p-styrenesulfonate)-enhanced Ag nanoclusters.

Poly(sodium-p-styrenesulfonate)-enhanced and D-penicillamine stabilized Ag nanoclusters (PSS-DPA-AgNCs) were prepared using one-step ultraviolet irradiation combined with microwave heating method, and the effects of the AgNCs photo-luminescence performance based on different types of polyelectrolytes and energy suppliers were studied detailedly. The as-prepared AgNCs can be used as a viable fluorescent probe for monitoring indirectly iron(II) lactate hydrate (ILH) and ammonium ferric citrate (AFC), respectively. The fluorescence (FL) quenching of PSS-DPA-AgNCs by Fe3+ (it is obtained from oxidized ILH/ionized AFC) mainly derives from a dynamic quenching process. Excellent linear relationships exist between the FL quenching degree of the AgNCs and the concentrations of ILH/AFC in the range of 0.17-6.00/0.067-3.33 µmol·L-1, and corresponding limit of detection (at 3σ/slope) is 12.4/6.04 nmol·L-1. Moreover, the AgNCs probe was extended to the assays of ILH in tablets, solid beverage or ILH additive and AFC in two kinds of edible salts or syrup with satisfactory results compared with the standard 1, 10-phenanthroline method. In addition, the AgNCs probe reveals a good temperature sensing capability.

Boron doped carbon dots as a multifunctional fluorescent probe for sorbate and vitamin B12.

Boron doped carbon dots (B-CD) were synthesized by a one-step hydrothermal method using phenylboronic acid as the starting material. They have an average size of about 3.3 nm, with excitation/emission wavelength of 247/323 nm and a quantum yield of 12%. The B-CD is shown to be viable fluorescent probe for sorbate (PS) and vitamin B12 (VB12). The fluorescence (FL) of the B-CD is quenched in the presence of PS or VB12 mainly coming from inner filter effect (IFE), but Förster resonance energy transfer (FRET) from the B-CD (as a donor) to PS/VB12 (as an acceptor) cannot be excluded. The probe enables PS to be detected by fluorometry with a linear response in the 0.20-24 µM concentration range and a 6.1 nM detection limit (at 3σ/slope). For VB12, the data are 0.20-30 µM and 8.0 nM. Graphical abstract Boron doped carbon dots (B-CD) as a probe was prepared by phenylboronic acid as single starting material via one-step hydrothermal method, which has remarkable selectivity and high sensitivity for monitoring PS/VB12. The fluorescence quenching of B-CD by PS/VB12 mainly comes from inner filter effect.

A multifunctional sensor for selective and sensitive detection of vitamin B12 and tartrazine by Förster resonance energy transfer.

We used thiamine nitrate (TN) as single material to fabricate nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) with a quantum yield of 10.4% through one-pot hydrothermal method, and its properties were characterized by TEM, XPS, FTIR, fluorescence (FL) and UV-vis spectrophotometer, respectively. The fluorescence of N,S-CQDs was effectively quenched in the presence of vitamin B12 (VB12)/tartrazine due to Förster resonance energy transfer (FRET). Moreover, the rate (KT) and efficiency (E%) of energy transfer from N,S-CQDs (as a donor) to VB12/tartrazine (as an acceptor) enhanced with increasing the concentrations of acceptor, and the KT and E% were also varied with the change of excitation wavelengths (from 338 to 408 nm). Based on this principle, a multifunctional fluorescence probe was designed for selective and sensitive detection of VB12/tartrazine with a detection limit (3σ/slope) of 15.6/18.0 nmol/L. Meanwhile, the proposed method was successfully employed to detect VB12/tartrazine in milk and several beverages with a recovery range of 97.5-104.2%/91.0-110.6%.

Effects of Different Levels of Intra-Abdominal Pressure on the Postoperative Hepatic Function of Patients Undergoing Laparoscopic Cholecystectomy: A Systematic Review and Meta-Analysis.

OBJECTIVE: The aim of this meta-analysis is to compare the differences in postoperative markers of the hepatic function under different intra-abdominal pressures in laparoscopic cholecystectomy (LC). METHODS: Several databases were searched for control studies, and then the weighted data were pooled with random-effect models. RESULTS: A total of 11 studies involving 865 patients were included. The meta-analysis reveals that the level of the aspartate aminotransferase and alanine transaminase of the low-pressure group has a lower postoperative increase than the moderate-pressure group (P<0.001). The level of the aspartate aminotransferase and alanine transaminase of the moderate-pressure group has a lower postoperative increase than the high-pressure group (P<0.001). Totally, the effect of lower pressure LC on postoperative hepatic functions is less significant than that of the higher one. Potential subgroup analysis does not modify these results. CONCLUSIONS: The recommended pressure in LC is suggested to be lower so as to result in a better surgical safety, especially for special populations.

Data of fluorescence, UV-vis absorption and FTIR spectra for the study of interaction between two food colourants and BSA.

In this data article, the fluorescence, UV-vis absorption and FTIR spectra data of BSA-AR1/AG50 system were presented, which were used for obtaining the binding characterization (such as binding constant, binding distance, binding site, thermodynamics, and structural stability of protein) between BSA and AR1/AG50.

Interactions of two food colourants with BSA: Analysis by Debye-Hückel theory.

We have focused on exploring pH- and ionic strength-modulated binding of acid red 1 (AR1) and acid green 50 (AG50) with bovine serum albumin (BSA) by fluorescence, UV-vis absorption and FTIR spectra. The results implied that the quenching mechanism of BSA-AR1/AG50 system was a static quenching, electrostatic force dominated the formation of BSA-AR1/AG50 complex, and the binding affinity of AR1 was greater than that of AG50 on the subdomain IIA of BSA. Moreover, their true thermodynamic binding constant (Keq), true free energy change (ΔG(0)I→0), and effective charge (ZP) in the anion receptor pocket of BSA were calculated using Debye-Hückel limiting law. The local charge bound by AR1/AG50 rather than the overall or surface charge of BSA played a key role in determining their interaction strength. Besides, the thermal and structural stabilization of BSA was discussed by analyzing the changes of Tm and Hurea without/with the addition of AR1/AG50, respectively.

Comparison of interactions between three food colorants and BSA.

Fast Green FCF (FCF), Patent Blue V (PBV) and Acid Blue 1 (AB1) are used as food colorants. Multiple spectroscopic techniques were employed to probe in depth the affinity of FCF/PBV/AB1 with BSA in different pH and/or salt concentrations. The results showed that FCF/PBV/AB1 quenched the intrinsic fluorescence of BSA by a static process, and electrostatic force dominated the formation of BSA-FCF/PBV/AB1 complex which was confirmed by the effects of salt on their interactions. Subdomain IIA was the primary binding site for FCF/PBV/AB1 on BSA in the pH range of 5.5-7.4, while both Trp 212 and Trp 134 residues of BSA might be bound by FCF/PBV/AB1 at pH 4.8. The K values suggested that the binding ability of three food colorants with BSA was FCF>PBV>AB1. The results of UV-vis absorption, synchronous fluorescence, 3D fluorescence and FT-IR spectra proved that the structure of BSA altered by FCF/PBV/AB1.