Latest ArticlesThirteen new fluorine-containing drugs, which have been granted approval by the US Food and Drug Administration (FDA) in 2020, are profiled in this review. Therapeutic areas of these new fluorinated pharmaceuticals include medicines and diagnostic agents for Cushing's disease, neurofibromatosis, migraine, Alzheimer's disease, myelodysplastic syndromes, hereditary angioedema attacks, and various cancers. Molecules of these approved drugs feature aromatic fluorine (Ar-F) (11 compounds), aromatic Ar-CF3 (1), aliphatic CHF (1) and CF2 (1) groups. For each compound, we provide a spectrum of biological activity, medicinal chemistry discovery, and synthetic approaches.
In this work, a very simple dual-readout lateral flow test strip (LFTS) platform was developed for sensitive detection of alkaline phosphatase (ALP) based on a portable device. In this assay, quantum dots (QDs) conjugated with bovine serum albumin (QDs-BSA) were chosen as fluorescence signal labels. In the absence of ALP, MnO2 nanosheets aggregate on the test line and exhibit an obvious brown color, which can be observed by naked eyes to realize semi-qualitative analysis. Meanwhile, fluorescence intensity of QDs-BSA can also be effectively quenched by MnO2 nanosheets due to inner-filter effect. Correspondingly, in the presence of ALP, ALP can catalyze the hydrolysis of ascorbic acid 2-phosphate (AAP) to generate L-ascorbic acid (AA), which can reduce MnO2 into Mn2+, accompanying with the obvious fluorescence recovery of the QDs. By simply monitoring the change of colorimetric and fluorescent signal on the test line, trace amount of ALP can be quantitatively detected. Under the optimal conditions, measurable evaluation of ALP was reached in a linear range from 1 U/L to 20 U/L with a detection limit of 0.7 U/L based on fluorescence signal. Furthermore, this colorimetric/fluorescent dual-readout assay was successfully applied to monitor ALP in human serum samples, showing its great potential as a point of care biosensor for clinical diagnosis.
Ultrabroad spectral absorption is required for semiconductor photocatalysts utilized for solar-to-chemical energy conversion. The light response range can be extended by element doping, but the photocatalytic performance is generally not enhanced correspondingly. Here we present a solid alkali activation strategy to synthesize near-infrared (NIR) light-activated carbon-doped polymeric carbon nitride (A-cPCN) by combining the copolymerization of melamine and 1, 3, 5-trimesic acid. The prepared A-cPCN is highly crystalline with a narrowed bandgap and enhanced efficiency in the separation of photogenerated electrons and holes. Under irradiation with NIR light (780 nm ≥ λ ≥ 700 nm), A-cPCN shows an excellent photocatalytic activity for H2 generation from water with rate of 165 µmol g−1 h−1, and the photo-redox activity for H2O2 production (109 µmol g−1 h−1) from H2O and O2, whereas no observed photocatalytic activity over pure PCN. The NIR photocatalytic activity is due to carbon doping, which leads to the formation of an interband level, and the alkali activation that achieved shrinking the transfer distance of photocarriers. The current synergistic strategy may open insights to fabricate other carbon-nitrogen-based photocatalysts for enhanced solar energy capture and conversion.
This work presents a novel strategy for engineering a GC stationary phase with high selectivity, inertness and thermal stability by introducing the 3D π-rich TP moieties to the terminals of a polar chain polymer. Herein, we provide the first example, i.e., a new TP-terminated polycaprolactone polymer (TPP) as the stationary phase for GC analyses. As demonstrated, the TPP column achieved distinctly improved inertness to fatty acids and aldehydes, and dramatically enhanced thermal stability (about 100 ℃ higher) over the PCL column. Also, the TPP column exhibited high resolving capability towards the positional isomers of phenols, anilines and alkylated/halobenzenes and showed good potential in detecting minor impurities in chemical products. Importantly, the proposed strategy is facile, feasible and generally applicable to analogous polymers.
Exosomal miRNAs, as potential biomarkers in liquid biopsy for cancer early diagnosis, have aroused widespread concern. Herein, an electrochemical biosensor based on DNA "nano-bridge" was designed and applied to detect exosomal microRNA-21 (miR-21) derived from breast cancer cells. In brief, the target miR-21 can specifically open the hairpin probe 1(HP1) labeled on the gold electrode (GE) surface through strand displacement reaction. Thus the exposed loop region of HP1 can act as an initiator sequence to activate the hybridization chain reaction (HCR) between two kinetically trapped hairpin probes: HP2 immobilized on the GE surface and biotin labeled HP3 in solution. Cascade HCR leads to the formation of DNA "nano-bridge" tethered to the GE surface with a great deal of "piers". Upon addition of avidin-modified horseradish peroxidase (HRP), numerous HRP were bound to the formed "nano-bridge" through biotin-avidin interaction to arouse tremendous current signal. In theory, only a single miR-21 is able to trigger the continuous HCR between HP2 and HP3 until all of the HP2 are exhausted. Therefore the proposed biosensor achieved ultrahigh sensitivity toward miR-21 with the detection limit down to 168 amol/L, as well as little cross-hybridization even at the single-base-mismatched level. Successful attempts were also made in the detection of exosomal miR-21 obtained from the MCF-7 of breast cancer cell line. To our knowledge, this is the first attempt to built horizontal DNA nano-structure on the electrode surface for exosomal miRNAs detection. In a word, the high sensitivity, selectivity, low cost make the proposed method hold great potential application for early point-of-care (POC) diagnostics of cancer.
Bandgap engineering through single-atom site binding on semiconducting photocatalyst can boost the intrinsic activity, selectivity, carrier separation, and electron transport. Here, we report a mixed-valence Ag(0) and Ag(Ⅰ) single atoms co-decorated semiconducting chalcopyrite quantum dots (Ag/CuFeS2 QDs) photocatalyst. It demonstrates efficient photocatalytic performances for specific organic dye (rhodamine B, denoted as RhB) as well as inorganic dye (Cr(Ⅵ)) removal in water under natural sunlight irradiation. The RhB degradation and Cr(Ⅵ) removal efficiencies by Ag/CuFeS2 QDs were 3.55 and 6.75 times higher than those of the naked CuFeS2 QDs at their optimal pH conditions, respectively. Besides, in a mixture of RhB and Cr(Ⅵ) solution under neutral condition, the removal ratio has been elevated from 30.2% to 79.4% for Cr(Ⅵ), and from 95.2% to 97.3% for RhB degradation by using Ag/CuFeS2 QDs after 2 h sunlight illumination. The intrinsic mechanism for the photocatalytic performance improvement is attributed to the narrow bandgap of the single-atomic Ag(Ⅰ) anchored CuFeS2 QDs, which engineers the electronic structure as well as expands the optical light response range. Significantly, the highly active Ag(0)/CuFeS2 and Ag(Ⅰ)/CuFeS2 effectively improve the separation efficiency of the carriers, thus enhancing the photocatalytic performances. This work presents a highly efficient single atom/QDs photocatalyst, constructed through bandgap engineering via mixed-valence single noble metal atoms binding on semiconducting QDs. It paves the way for developing high-efficiency single-atom photocatalysts for complex pollutions removal in dyeing wastewater environment.
5-Methylcytosine (5mC) is the most important epigenetic modification in mammals. The active DNA demethylation could be achieved through the ten-eleven translocation (TET) protein-mediated oxidization of 5mC with the generation of 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). It has been known that 5mC, 5hmC and 5fC play critical roles in modulating gene expression. However, unlike the 5mC, 5hmC, and 5fC, the functions of 5caC are still underexplored. Investigation of the functions of 5caC relies on the accurate quantification and localization analysis of 5caC in DNA. In the current study, we developed a method by chemical conversion in conjugation with ligation-based real-time quantitative PCR (qPCR) for the site-specific quantification of 5caC in DNA. This method depends on the selective conversion of 5caC to form dihydrouracil (DHU) by pyridine borane treatment. DHU behaves like thymine and pairs with adenine (DHU-A). Thus, the chemical conversion by pyridine borane leads to the transformation of base paring from 5caC-G to DHU-A, which is utilized to achieve the site-specific detection and quantification of 5caC in DNA. As a proof-of-concept, the developed method was successfully applied in the site-specific quantification of 5caC in synthesized DNA spiked in complex biological samples. The method is rapid, straightforward and cost-effective, and shows promising in promoting the investigation of the functional roles of 5caC in future study.
The effects of different species and concentrations' signal molecules on aerobic activated sludge system were investigated through batch experiments. Results showed that the fastest NH4+-N oxidization rate and the most extracellular polymeric substances (EPS) secretion were obtained by adding 5 nmol/L N-hexanoyl-l-homoserine lactone (C6-HSL) into the aerobic activated sludge. Further study investigated the correlation among N-acyl-homoserine lactones-mediated quorum sensing (AHLs-mediated QS), nutrient removal performances and microbial communities with the long-term addition of 5 nmol/L C6-HSL. It was found that C6-HSL-manipulation could enhance the stability and optimize the decontamination performance of aerobic granular sludge (AGS) system. Microbial compositions considerably shifted with long-term C6-HSL-manipulation. Exogenous C6-HSL-manipulation inhibited quorum quenching-related (QQ-related) activities and enhanced QS-related activities during the stable period. The proposed C6-HSL-manipulation might be a potential technology to inhibit the growth of harmful bacteria in AGS, which could provide a theoretical foundation for the realization of more stable biological wastewater treatments.
Pillar[5]arenes, designed and prepared by Ogoshi et al. in 2008 initially, refer to fifth classical macrocyclics. Among a wide range of pillar[5]arenes, rim-differentiated pillar[5]arenes containing five identical substituents on one rim and five different identical groups on the other rims are considered the most noteworthy type of pillar[5]arenes. As compared with the perfunctionalized pillar[5]arene, the self-assembly properties of rim-differentiated pillar[5]arenes have more varieties. On the other hand, in comparison with other types of pillar[5]arenes, the rim-differentiated pillar[5]arenes exhibit a more rigid symmetrical structure. In the present review, the synthetic methods, host-guest interactions, self-assembly properties and applications of rim-differentiated pillar[5]arenes are summarized. Hopefully, this review will be conducive to researchers in macrocyclic supramolecular chemistry.
A hydrophobic carbon dots (Glc-OCDs) derived from octadecylamine and glucose were successfully synthesized for the first time and then grafted onto the porous silica surface by the "Nano-on-Micro" strategy, which was served as a new stationary phase (Sil-Glc-OCDs) for reversed-phase liquid chromatography. The structure of this stationary phase was carefully verified by laser scanning confocal microscope, Fourier transform infrared spectrometry, elemental analysis, contact angle measurement, etc. Several analytes including seven polycyclic aromatic hydrocarbons, eight alkylbenzenes, eight phenols and seven sulfonamides can be well separated on this stationary phase. Better separation performance for certain analytes over commercial C18 column was obtained. Interestingly, this stationary phase exhibited excellent chromatographic selectivity in the separation of the isomers of tert‑butylbenzene, sec‑butylbenzene, isobutylbenzene and n-butylbenzene. In addition, this new Sil-Glc-OCDs column was also applied for detection of calycosin-7-glucoside, ononin, calycosin, formononetin, genistein and isorhamnetin in the extract of Radix Astragali, which were found that the concentration was 0.15 g/L, 0.088 g/L, 0.14 g/L, 0.086 g/L, 0.18 g/L and 0.29 g/L, respectively. We believe that this CDs-grafted silica materials are promising for chromatographic separation.
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