Dynamic Interchain Motion in 1D Tetrathiafulvalene-Based Coordination Polymers for Highly Sensitive Molecular Recognition.

The application of electrically conductive 1D coordination polymers (1D CPs) in nanoelectronic molecular recognition is theoretically promising yet rarely explored due to the challenges in their synthesis and optimization of electrical properties. In this regard, two tetrathiafulvalene-based 1D CPs, namely [Co(m-H2TTFTB)(DMF)2(H2O)]n (Co-m-TTFTB), and {[Ni(m-H2TTFTB)(CH3CH2OH)1.5(H2O)1.5]·(H2O)0.5}n (Ni-m-TTFTB) are successfully constructed. The shorter S···S contacts between the [M(solvent)3(m-H2TTFTB)]n chains contribute to a significant improvement in their electrical conductivities. The powder X-ray diffraction (PXRD) under different organic solvents reveals the flexible and dynamic structural characteristic of M-m-TTFTB, which, combined with the 1D morphology, lead to their excellent performance for sensitive detection of volatile organic compounds. Co-m-TTFTB achieves a limit of detection for ethanol vapor down to 0.5 ppm, which is superior to the state-of-the-art chemiresistive sensors based on metal-organic frameworks or organic polymers at room temperature. In situ diffuse reflectance infrared Fourier transform spectroscopy, PXRD measurements and density functional theory calculations reveal the molecular insertion sensing mechanism and the corresponding structure-function relationship. This work expands the applicable scenario of 1D CPs and opens a new realm of 1D CP-based nanoelectronic sensors for highly sensitive room temperature gas detection.

Accessible Tetrathiafulvalene Moieties in a 3D Covalent Organic Framework for Enhanced Near-Infrared Photo-Thermal Conversion and Photo-Electrical Response.

Redox-active tetrathiafulvalene (TTF)-based covalent organic frameworks (COFs) exhibit distinctive electrochemical and photoelectrical properties, but their prevalent two-dimensional (2D) structure with densely packed TTF moieties limits the accessibility of redox center and constrains their potential applications. To overcome this challenge, an 8-connected TTF linker (TTF-8CHO) is designed as a new building block for the construction of three-dimensional (3D) COFs. This approach led to the successful synthesis of a 3D COF with the bcu topology, designated as TTF-8CHO-COF. In comparison to its 2D counterpart employing a 4-connected TTF linker, the 3D COF design enhances access to redox sites, facilitating controlled oxidation by I2 or Au3+ to tune physical properties. When irradiated with a 0.7 W cm-2 808 nm laser, the oxidized 3D COF samples ( I X - ${\mathrm{I}}_{\mathrm{X}}^{-}$ @TTF-8CHO-COF and Au NPs@TTF-8CHO-COF) demonstrated rapid temperature increases of 239.3 and 146.1 °C, respectively, which surpassed those of pristine 3D COF (65.6 °C) and the 2D COF counterpart (6.4 °C increment after I2 treatment). Furthermore, the oxidation of the 3D COF heightened its photoelectrical responsiveness under 808 nm laser irradiation. This augmentation in photothermal and photoelectrical response can be attributed to the higher concentration of TTF·+ radicals generated through the oxidation of well-exposed TTF moieties.

Coordination-Modulated Metal Tetrathiafulvalene Octacarboxylate Frameworks for High-Performance Lithium-Ion Battery Anodes.

Modulation of the ligands and coordination environment of metal-organic frameworks (MOFs) has been an effective and relatively unexplored avenue for improving the anode performance of lithium-ion batteries (LIBs). In this study, three MOFs are synthesized, namely, M4 (o-TTFOB)(bpm)2 (H2 O)2 (where M is Mn, Zn, and Cd; o-H8 TTFOB is ortho-tetrathiafulvalene octabenzoate; and bpm is 2,2'-bipyrimidine), based on a new ligand o-H8 TTFOB with two adjacent carboxylates on one phenyl, which allows us to establish the impact of metal coordination on the performance of these MOFs as anode materials in LIBs. Mn-o-TTFOB and Zn-o-TTFOB, with two more uncoordinated oxygen atoms from o-TTFOB8- , show higher reversible specific capacities of 1249 mAh g-1 and 1288 mAh g-1 under 200 mA g-1 after full activation. In contrast, Cd-o-TTFOB shows a reversible capacity of 448 mAh g-1 under the same condition due to the lack of uncoordinated oxygen atoms. Crystal structure analysis, cyclic voltammetry measurements of the half-cell configurations, and density functional theory calculations have been performed to explain the lithium storage mechanism, diffusion kinetics, and structure-function relationship. This study demonstrates the advantages of MOFs with high designability in the fabrication of LIBs.

A simple and sensitive LC-MS/MS method for therapeutic drug monitoring of digoxin in children.

This short communication introduced a simple and sensitive LC-MS/MS method for therapeutic drug monitoring of digoxin in children with the lower limit of quantitation of 0.2 ng/mL based on 30 µL of plasma. The plasma sample was pretreated by one-step protein precipitation. Then the chromatographic separation was performed on a short C-18 column with a total run time of 2.4 min. The detection was achieved through multiple reaction monitoring using positive ionization mode on a triple quadrupole mass spectrometer. The linear range of digoxin in human plasma was among 0.2-6.4 ng/mL. The intra-day and inter-day accuracies of digoxin ranged from -6.0 % to 10.1 % and imprecisions were less than 8.8 %. The extraction recovery rate of digoxin in plasma samples was above 90 %. Matrix factor normalized by internal standard was within acceptance criteria. This method was fully verified and applied to determine the plasma digoxin concentrations of 43 pediatric patients. It is approved appropriate and practical for the therapeutic drug monitoring of digoxin in routine clinical laboratory practice, especially for children.

Redox-Active Mixed-Linker Metal-Organic Frameworks with Switchable Semiconductive Characteristics for Tailorable Chemiresistive Sensing.

Metal-organic frameworks (MOFs), with diverse metal nodes and designable organic linkers, offer unique opportunities for the rational engineering of semiconducting properties. In this work, we report a mixed-linker conductive MOF system with both tetrathiafulvalene and Ni-bis(dithiolene) moieties, which allows the fine-tuning of electronic structures and semiconductive characteristics. By continuously increasing the molar ratio between tetrathiafulvalene and Ni-bis(dithiolene), the switching of the semiconducting behaviors from n-type to p-type was observed along with an increase in electrical conductivity by 3 orders of magnitude (from 2.88×10-7  S m-1 to 9.26×10-5  S m-1 ). Furthermore, mixed-linker MOFs were applied for the chemiresistive detection of volatile organic compounds (VOCs), where the sensing performance was modulated by the corresponding linker ratios, showing synergistic and nonlinear modulation effects.

Redox-Active Metal-Organic Frameworks with Three-Dimensional Lattice Containing the m-Tetrathiafulvalene-Tetrabenzoate.

Metal-organic frameworks (MOFs) constructed by tetrathiafulvalene-tetrabenzoate (H4TTFTB) have been widely studied in porous materials, while the studies of other TTFTB derivatives are rare. Herein, the meta derivative of the frequently used p-H4TTFTB ligand, m-H4TTFTB, and lanthanide (Ln) metal ions (Tb3+, Er3+, and Gd3+) were assembled into three novel MOFs. Compared with the reported porous Ln-TTFTB, the resulted three-dimensional frameworks, Ln-m-TTFTB ([Ln2(m-TTFTB)(m-H2TTFTB)0.5(HCOO)(DMF)]·2DMF·3H2O), possess a more dense stacking which leads to scarce porosity. The solid-state cyclic voltammetry studies revealed that these MOFs show similar redox activity with two reversible one-electron processes at 0.21 and 0.48 V (vs. Fc/Fc+). The results of magnetic properties suggested Dy-m-TTFTB and Er-m-TTFTB exhibit slow relaxation of the magnetization. Porosity was not found in these materials, which is probably due to the meta-configuration of the m-TTFTB ligand that seems to hinder the formation of pores. However, the m-TTFTB ligand has shown to be promising to construct redox-active or electrically conductive MOFs in future work.

Enhancing the photothermal conversion of tetrathiafulvalene-based MOFs by redox doping and plasmon resonance.

Near-infrared (NIR) photothermal materials hold great promise for use in several applications, particularly in photothermal therapy, diagnosis, and imaging. However, current NIR responsive materials often show narrow absorption bands and low absorption efficiency, and have long response times. Herein, we demonstrate that the NIR absorption of tetrathiafulvalene-based metal-organic frameworks (MOFs) can be tuned by redox doping and using plasmonic nanoparticles. In this work, a MOF containing redox-active tetrathiafulvalene (TTF) units and Dy-carboxylate chains was constructed, Dy-m-TTFTB. The NIR absorption of the as-synthesized Dy-m-TTFTB was further enhanced by Ag+ or I2 oxidation, transforming the neutral TTF into a TTF˙+ radical state. Interestingly, treatment with Ag+ not only generated TTF˙+ radicals, but it also formed Ag nanoparticles (NPs) in situ within the MOF pores. With both TTF˙+ radicals and Ag NPs, Ag NPs@Dy-m-TTFTB was shown to exhibit a wide range of absorption wavelengths (200-1000 nm) and also a high NIR photothermal conversion. When the system was irradiated with an 808 nm laser (energy power of 0.7 W cm-2), Ag NPs@Dy-m-TTFTB showed a sharp temperature increase of 239.8 °C. This increase was higher than that of pristine Dy-m-TTFTB (90.1 °C) or I2 treated I3 -@Dy-m-TTFTB (213.0 °C).

Coordination-bond-directed synthesis of hydrogen-bonded organic frameworks from metal-organic frameworks as templates.

Controlled synthesis of hydrogen-bonded organic frameworks (HOFs) remains challenging, because the self-assembly of ligands is not only directed by weak hydrogen bonds, but also affected by other competing van der Waals forces. Herein, we demonstrate the coordination-bond-directed synthesis of HOFs using a preformed metal-organic framework (MOF) as the template. A MOF (CuI-TTFTB) based on two-coordinated CuI centers and tetrathiafulvalene-tetrabenzoate (TTFTB) ligands was initially synthesized. CuI-TTFTB was subsequently oxidized to the intermediate (CuII-TTFTB) and hydrated to the HOF product (TTFTB-HOF). Single-crystal-to-single-crystal (SC-SC) transformation was realized throughout the MOF-to-HOF transformation so that the evolution of structures was directly observed by single-crystal X-ray diffraction. The oxidation and hydration of the CuI center are critical to breaking the Cu-carboxylate bonds, while the synergic corbelled S⋯S and π⋯π interactions in the framework ensured stability of materials during post-synthetic modification. This work not only provided a strategy to guide the design and discovery of new HOFs, but also linked the research of MOFs and HOFs.

High-Performance Lithium-Ion Capacitors Based on Porosity-Regulated Zirconium Metal-Organic Frameworks.

Comprised of a battery anode and a supercapacitor cathode, hybrid lithium-ion capacitors (HLICs) are found to be an effective solution to realize both high power density and high energy density at the same time. Organic-inorganic hybrid materials with well-organized framework guided by the reticular chemistry are one of the promising anode materials for HLICs because of rich active sites and ordered porosity. Herein, metal-organic framework consisting of Zr4+ metal ions and tetrathiafulvalene-based ligands (Zr-MOF) is proposed as the pseudocapacitive anode of HLICs. The Zr-MOF possesses high stability, high crystallinity, and multiple meso-microporous channels favorable for ion transport. The as-prepared Zr-MOF||activated carbon HLICs present high energy density (122.5 Wh kg-1 ), high power density (12.5 kW kg-1 ), and stable cycling performance (86% capacity retention after 1000 cycles at 2000 mA g-1 ) within the operating voltage range of 1.0-4.0 V. The results expand the direct application of MOF for bridging the performance gap between batteries and supercapacitors.

Persistent Radical Tetrathiafulvalene-Based 2D Metal-Organic Frameworks and Their Application in Efficient Photothermal Conversion.

A series of stable radical 2D metal-organic frameworks has been assembled. (m-TTFTB)3 (m-Tetrathiafulvalene-tetrabenzoate) trimer building blocks are beneficial for the stability of the radicals due to delocalization of the unpaired electron. Hexanuclear rare-earth-cluster-based 1D chains further enhance the stability of the frameworks. The radical state of the middle TTF in the trimer has been observed by the change of central C-C and C-S bond distances and the configuration of the TTF by single-crystal X-ray diffraction. The radical characteristics are also confirmed by electron paramagnetic resonance, UV/Vis-NIR absorption, and X-ray photoelectron spectroscopy experiments. Stability tests showed that the radicals are stable even in solutions and under acid/base environments (pH 1-12). Owing to efficient light absorption due to intramolecular charge transfer, low thermal conductivity, and outstanding stability, the radical 2D Dy-MOF shows excellent photothermal properties, an increase of 34.7 °C within 240 s under one-sun illumination.

[Polymorphism of Platelet Specific Antigens (HPA-1-5, 15) in Han Donors in the North Area of Henan Province].

OBJECTIVE: To study the gene polymorphism distribution characteristics of human platelet HPA-1-5 and 15 blood group antigens and construct a certain scale of platelet HPA database in the north area of Henan Province so as to provide platelet apheresis for clinical departments. METHODS: Using polymerase chain reaction with sequence-specific primers (PCR-SSP), the genotyping of HPA-1-5 and 15 system was carried out; the periperal blood of 500 healthy Han donors in north area of Henan Province was collected randomly, the gene and genotype frequencies were detected by direct counting method, and the population distribution frequncy of HPA genes was analyzed by Hardy-Weinberg balance test, and compared with other regions and ethnics by using χ(2) test. RESULTS: There was statistically significant (P < 0.05) of increase HPA-3b and HPA-5a in North area of Henan Province, compared with Chinese Han population; the HPA-3b and 5a increase and HPA-2a decrease were statistically significant (P < 0.05), compared with Ethnic minority of China. There was partly increase of HPA-1a, 2a, 3a and 5a, compared with different regions and ethnic in abroad. HPA allele genes of 500 Han donors in the North area of Henan Province were as follows: 0.985 and 0.015 for 1a and 1b; 0.924 and 0.076 for 2a and 2b; 0.469 and 0.531 for 3a and 3b; 1.000 and 1.000 for 4a and 5a; 0.532 and 0.468 for 15a and 15b, respectively. HPA allele gene frequencies were 1aa0.970, 1ab0.030; 2aa0.848, 2ab0.152; 3aa0.222, 3ab0.494, 3bb0.284; 4aa1.000; 5aa1.000; 15aa0.282, 15ab0.500, 15bb0.218. Compared with other regions and ethnic, HPA gene frequencies partly had statistical significance. CONCLUSION: Distribution of HPA allele frequencies in the North area of Henan province is in accordence with the Hardy-Weinberg law. There are race and regional differences in HPA allele gene frequencies, compared with other regions and countries. And the HPA systems HPA-3 and 15 display the genetic polymorphisms, which provides a theoretical basis for the relevant research of the same type platelet infusion and alloimmune thrombocytopenia.

[Synergistic effect of targeted inhibition of MEK/ERK and PI3K/AKT survival signaling pathways on induction of apoptosis in melanoma].

OBJECTIVE: The treatment of metastatic melanoma by conventional chemotherapeutic agents remains unsatisfactory. The present study was undertaken to reveal the role of co-inhibition of survival signaling pathways in apoptosis of melanoma cells. METHODS: A panel of human melanoma cell lines and fresh melanoma isolates was assessed for their sensitivity to the MEK inhibitor U0126 and/or AKT inhibitor LY294002. The proliferation and apoptosis of the cells were examined after treatment with the inhibitors. RESULTS: Constitutive activation of ERK1/2 and AKT was closely related to concentrations of serum in the culture medium (extracellular signals). The sensitivity of melanoma cells to apoptosis induced by inhibition of MEK/ERK was not correlated with the active BRAF mutation (BRAF(V600E)). Inhibition of MEK/ERK predominantly induced apoptosis; whereas inhibition of PI3K/AKT primarily inhibited proliferation. Co-inhibition of MEK/ERK1/2 and PI3K/AKT synergistically induced apoptosis. CONCLUSION: Co-targeting MEK/ERK and PI3K/AKT pathways may further improve treatment for melanoma.

[Analysis of chromosomal abnormalities in pancreatic cancer by spectral karyotyping].

OBJECTIVE: to investigate the chromosomal characteristics of pancreatic ductal adenocarcinomas by spectral karyotyping. METHODS: cytogenetic aberrations of pancreatic cancer cell line P2 established from a Chinese patient was investigated by spectral karyotyping (SKY). Chromosomal alterations were further evaluated in 10 cases of pancreatic cancer and 10 cases of chronic pancreatitis by two color fluorescence in situ hybridization (FISH) by using EGFR/CEP7 probe and paraffin embedded tissue samples. RESULTS: hypotriploid and 26 chromosomal aberrations were revealed in cell line P2. Recurrent chromosomal numerical alterations included loss of chromosome 4, 9, 18, 19, 22, Y, 10p, 15p, 8p, 6q and 12p, with gain of chromosome 7 and 12q. Frequent chromosomal structural abnormalities included der(9;15)(q10;q10), der(10)(3;10)(?;q26) and der(12)(8;12)(?;p13). Four of 10 cases showed EGFR copy number changes by FISH. CONCLUSIONS: highly complex chromosomal rearrangements occur in pancreatic cancers. Additional studies of more cases are needed, including FISH analysis of EGFR copy number changes, to reach a conclusion.

[Increased atria expression of receptor activity-modifying proteins in heart failure patients].

OBJECTIVE: Receptor activity-modifying proteins (RAMPs) determine the ligand specificity of the calcitonin receptor-like receptor (CRLR); co-expression of RAMP1 and CRLR results in a calcitonin gene related peptide (CGRP) receptor, whereas the association of RAMP2 or RAMP3 with CRLR gives an adrenomedullin(ADM) receptor. As CGRP and ADM may play a beneficial role in heart failure, this study aimed at the question whether RAMPs mRNAs are changed in heart failure. METHODS: Semi-quantitative reverse transcription-PCR (RT-PCR) was used to detect and quantify the mRNAs of RAMP1 and RAMP3 in the atria of heart failing patients. RESULTS: It was found that the expressions of RAMP1, RAMP2 and RAMP3 mRNAs increased with the worsening of heart function, but the expressions of RAMP1 and RAMP2 mRNA decreased at level IV of heart failure. CONCLUSION: The above results demonstrated in the atria of heart failure patients an up-regulation of CGRP receptor by an increase of RAMP1 in association with CRLR and an up-regulation of ADM receptor by an increase of RAMP2 expression in association with CRLR, thus suggesting that CGRP and ADM receptors be playing a functional role in compensating the chronic heart failure in human.

[Comparison of three methods for quantitative analysis of LPO in different biological samples].

OBJECTIVE: To explore the optimized methods for detecting lipid peroxide (LPO) in biological samples and the reference value of LPO in human plasma. METHODS: Three most commonly adopted methods were used for detecting LPO in different biological samples simultaneously, and then their linearity, accuracy, precision, stability and detecting efficiency were compared. The methods were FOX assay, Modified iodometric assay and TBARS assay. The standard curve (linearity evaluation), rate of sample recovery (accuracy evaluation), reproducibility (precision evaluation), stability of reading number (stability evaluation), as well as the detected values of LPO in different sample systems by three methods simultaneously (detecting efficiency) were evaluated. The sample systems were: isolated low-density lipoprotein (LDL), supernatant of cell culture, and human plasma. RESULTS: When applied to detecting LPO in the isolated LDL sample system, FOX assay was found to have the most sensitive detecting efficiency, good accuracy and precision. When applied to detecting LPO in the supernatant of cell culture and human plasma sample systems, the Modified iodometric assay and TBARS assay showed better function than FOX assay; the rate of sample recovery of FOX assay 61.92% +/- 2.92% was obviously lower as compared with 99.00% +/- 2.65% of modified iodometric assay and 101.63% +/- 12.00% of TBARS assay; and the reproducibility of FOX assay 19.15% was also lower as compared with 4.36% of Modified iodometric assay and 3.14% of TBARS assay. The three methods all showed fine linearity and stability. The values of LPO concentration in normal human plasma were (14.189 +/- 4.889) mumol/L by Modified iodometric assay and (0.936 +/- 0.462) mumol/L by TBARS assay; these values were close to those in other reports. CONCLUSION: FOX assay was found to be most sensitive in the three methods for measurement of LPO in a relative pure sample system (such as isolated LDL). In complex sample system, however, the Modified iodometric assay and TBARS assay showed better function. The authors suggest that suitable method be chosen according to the nature of sample, that more than one method be chosen for plasma LPO assay in the same planned analysis, and that Modified iodometric assay and TBARS assay be worth the first choice.