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Implementing combination medication through crystal engineering technology receives increasing attention from researchers due to improvements in the clinical treatment effects as well as the physicochemical properties of the drug. Berberine (BER) is commonly used to treat gastroenteritis and bacterial diarrhea, with the problems of poor solubility and low oral bioavailability. Recently, it is found that gallic acid (GA) also has anti‐inflammatory and anti‐bacterial activities. Therefore, if the above‐mentioned two ingredients can be combined, it is possible to enhance the therapeutic effects and physicochemical properties of BER. Inspired by this, 8‐hydroxy‐7,8‐dihydroberberine (8H‐HBER) in this study is employed to react with gallic acid to yield BER gallate dihydrate (2BER‐2GA‐2 W). Furthermore, dissolution experiments demonstrate that the maximum apparent solubility (MAS) of 2BER‐2GA‐2 W in dilute hydrochloric acid solution medium (pH 1.2) has increased by 7 times compared to the commercial form of BER, because of avoiding the common‐ion effect. Moreover, 2BER‐2GA‐2 W has also obviously enhanced stability relative to the commercial form of BER. In addition, 2BER‐2GA‐2 W has a better inhibitory effect on Staphylococcus aureus (S. aureus) relative to the commercial form of BER. Hence, 2BER‐2GA‐2 W will be a promising solid‐state form of BER for its further development. [ABSTRACT FROM AUTHOR]

aim of this study was to analyze the epidemiological of gram-negative bloodstream infection (GNBSI) and establish a risk prediction model for mortality and acquiring multidrug resistant (MDR), the extended spectrum beta-lactamases (ESBLs) producing and carbapenem-resistant (CR) GNBSI. Methods: This retrospective study covered five years from January 2015 to December 2019. Data were obtained from Hospital Information System (HIS) and microbiology department records. The risk factors for mortality and acquiring MDR, ESBLs-producing and CR GNBSI were analyzed by univariable and multivariable analysis. Results: A total of 1018 GNBSI cases were collected. A majority of GNBSI patients were in hematology ward (23.77%). There were 38.61% patients who were assigned in the 41– 60 age group. Escherichia coli was the most common gram-negative organism (49.90%). Among isolates of GNBSI, 40.47% were found to be MDR strains, 34.09% were found to be ESBLs-producing strains and 7.06% were found to be CR strains. Escherichia coli was the most common MDR (71.36%) and ESBLs-producing strain (77.81%). Acinetobacter baumannii was the most common CR isolate (46.15%). Multivariate analysis indicated that diabetes mellitus, solid organ tumor, non-fermentative bacteria, MDR strain, central venous cannula, urinary catheter, therapy with carbapenems or tigecycline prior 30 days of infection were independent mortality risk factors for GNBSIs. Over all, therapy with tigecycline prior 30 days of infection was the mutual predictor for mortality of GNBSI, acquiring MDR, ESBLs-producing and CR GNBSI (OR, 8.221, OR, 3.963, OR, 3.588, OR, 9.222, respectively, all p < 0.001). Conclusion: Collectively, our study implies that patients who were diagnosed as GNBSI had a younger age. Therapy with tigecycline was the mutual and paramount predictor for mortality of GNBSI, acquiring MDR, ESBLs-producing and CR GNBSI. Our investigation had provided a theoretical basis for the use of antibiotics and prevention and control of hospital infection in our region. [ABSTRACT FROM AUTHOR]

The choline derivative (CD) and polyethylene-glycol (PEG) dually modified artemether (ARM) nanostructured lipid carriers (CD-PEG-ARM-NLC) have been designed to prolong the circulation of ARM in blood, as well as to develop targeting for new permeability pathways (NPPs) and erythrocyte choline carriers (ECCs) that are expressed on the Plasmodium-infected erythrocyte membrane. The CD-PEG-ARM-NLC constructed in this study was found to be able to target endoerythrocytic Plasmodium by increasing the drug concentration and residence time in the infected erythrocytic microenvironment and minimizing toxicity and side effects. CD-PEG-ARM-NLC was prepared using high-pressure homogenization followed by physicochemical characterization. The targeting ability of CD-PEG-NLC to infected erythrocytes probed by coumarin-6 was investigated by using fluorescence microscopy imaging. The SYBR Green I assay for parasite nucleic acid was adapted in order to assess the efficacy of inhibition against parasite growth in vitro. The antimalarial activity of ARM-loaded NLCs was evaluated by a Pearson four-day suppressive test in Pyy265BY-bearing mice. In vitro imaging indicated that the intracellular delivery of CD-PEG-ARM-NLC was efficiently taken up by the infected erythrocytes via ECCs and NPPs, which could be inhibited by addition of furosemide (an inhibitor of NPPs) and excessive choline (native substrate of ECCs). Moreover, in vitro and in vivo studies that evaluated antimalarial activity suggested that CD-PEG-ARM-NLC exhibited higher antimalarial activity in comparison to ARM-NLC and PEG-ARM-NLC. These findings suggested that choline and PEG dually modified NLC could be promising preparations for the production of hydrophobic antimalarial drugs, particularly for ARM. [ABSTRACT FROM AUTHOR]

As a quinazolinocarboline alkaloid, dehydroevodiamine (DHED) derived from Evodia rutaecarpa has recently gained attention because it improves memory failure in Alzheimer's mice. However, its solid forms, which have not yet been elucidated, could be a vital factor affecting its bioactivity and dosage form design. In this study, five DHED-related crystals, including DHED, its hydrochloride anhydrate (DHED·HCl), methanol solvate (DHED·HCl·CH3OH), dihydrate (DHED·HCl·2H2O) and trihydrate (DHED·HCl·3H2O), were obtained via re-crystallization. The five crystals fell into four distinct structural types based on the analysis of their similarities, and DHED·HCl·CH3OH and DHED·HCl·2H2O were proven to be isostructural. The water or solvent molecules incorporated into the crystal lattices via hydrogen bonds and π–π interactions were the main causes of formation of the distinct solid DHED hydrochloride forms. After dehydration at a high temperature, DHED·HCl·3H2O was transformed into an amorphous form (DHED·HCl-AM). Stability tests showed that the two isostructural crystals exhibited the same solid forms under all investigated conditions, and the humidity-induced phase transformation of DHED·HCl was closely tied to the moisture content. Solubility experiments showed that DHED achieved the highest solubility of approximately 3.6 μg ml−1, because of the loose molecular arrangements in DHED with the smallest packing coefficient and lack of π–π interactions. Additionally, transformations among evodiamine (EVO), DHED, DHED·HCl·2H2O and rutaecarpine (RUT) were also revealed: EVO was transformed into DHED·HCl·2H2O in hydrochloric acid-acidified acetone, and all of the solid forms of DHED hydrochloride were converted to RUT at 523 K. The transformations provided a novel and reliable approach to prepare these compounds. [ABSTRACT FROM AUTHOR]

Five novel crystals of acotiamide hydrochloride (AH) with solvates dimethyl formide (DMF), dimethyl sulfoxide (DMSO), ethyl acetate (EA) and water (W) [1AH‐1W‐1DMF, 1AH‐1DMSO‐I, 1AH‐1DMSO‐II, 1AH‐1W‐1DMSO and 2AH‐2DMSO‐1EA] were characterized using single‐crystal X‐ray diffraction, powder X‐ray diffraction, thermal analysis and Fourier transform infrared spectroscopy. The five crystals can be divided into four distinct structural types based on analysis of their similarities; 1AH‐1W‐1DMF and 1AH‐1W‐1DMSO are isostructural. The benzene rings in 1AH‐1DMSO‐I, 1AH‐1DMSO‐II and 2AH‐2DMSO‐1EA can rotate 180°, and the intramolecular hydrogen bond changes from an OH...C=O bond to an NH...OH bond relative to what is seen in 1AH‐1W‐1DMF and 1AH‐1W‐1DMSO. Phase transformation experiments show that a humidity‐induced phase transformation is closely tied to moisture content. [ABSTRACT FROM AUTHOR]

Docetaxel (DTX) solution has some serious adverse side effects. A redox-responsive DTX prodrug synthesized in our laboratory was used to prepare DTX prodrug self-assembled nanoparticles (DSNPs) with the method of nanoprecipitation. This study aimed at optimizing the formulation to develop stable preparation for the delivery of DTX. Single-factor test was used to evaluate the effects of the preparation concentration of DTX prodrug, stirring speed, the types of stabilizers and temperature on the prescription process of DSNPs. The particle size and polydispersity index were selected as the evaluation indexes. The entrapment efficiency, drug-loading, size distribution and zeta potential were characterized by UPLC and Zetasizer, respectively. The stability and cellular behavior of DSNPs were investigated by Zetasizer, LC–MS/MS and confocal laser scanning microscope, respectively. The particle size, entrapment efficiency and drug-loading of DSNPs were 173.8 ± 1.4 nm, 98.8% ± 0.1%, and 47.8% ± 0.9%, respectively. DSNPs showed good stability during the storage of 30 days, and were taken into the cells in a time-dependent and concentration-dependent manner. The method of nanoprecipitation could be used to entrap DTX. The preparation method was simple, and the quality of DSNPs was stable and reliable. Through the optimization of the formulation, we obtained uniform and stable DSNPs, which could escape from lysosomes of tumor cells. The optimized formulations were stable for intravenous administration. This study could provide scientific support for the development of nano-drug delivery system of small anti-tumor drug. [ABSTRACT FROM AUTHOR]

An ultrahigh-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous determination of sterigmatocystin, verruculogen, enniatin A, fusarenon-X, fumonisins B1, B2, B3, aflatoxins B1, B2, G1, G2, ochratoxin A, deoxynivalenol, 3-acetyldeoxynivalenol, 5-acetyldeoxynivalenol, and zearalenone. The mycotoxins were extracted and cleaned up using a multitoxin column, separated on a C18 column, and then detected on a triple-quadrupole mass spectrometer. The limits of detection and quantification ranged within 0.2–2 µg/kg and 1–10 µg/kg, respectively. The recoveries ranged from 70.8 to 118.4%, with relative standard deviations below 15%. The method was used to analyze 80 samples obtained from Shandong Province in China. Fifty-eight samples were contaminated with 10 mycotoxins at concentrations ranging from 1.4 to 6566.1 µg/kg. Some samples exceeded the maximum limits in China and in European regulations for mycotoxins in unprocessed maize. [ABSTRACT FROM PUBLISHER]

The remarkable catalytic properties of enzymes contribute to their unique 3D structures and arrangement of amino acid residues, which provide a blueprint for the design of artificial enzymes. Here, a series of peptide catalysts (PCs) that mimic the unique orientation and function of β-glycosyl hydrolases were designed. Transmission electron microscopy (TEM), fluorescence analysis, circular dichroism spectroscopy, X-ray diffraction and computational modeling were used to investigate and compare the relationship of the fibrinous structure of PCs with its glycoside hydrolysis activity. These results indicated that the catalytic activity of PCs was not only related to their amyloid-like structures, but it can also be influenced by the site, species, molecular arrangement and steric hindrance of the amino acid sequence. What's more, this is the first report on peptide-inspired catalysts that mimic the natural cellobiose hydrolases. All this provided insights into the potential use of peptide nanoenzymes in the generation of efficient artificial enzymes. [ABSTRACT FROM AUTHOR]

A fluorescence magnetic biosensor for the DNA methyltransferase activity was developed based on the cooperative amplification by combining the magnetic nanoparticles synergistic exonuclease III (Exo III)-assisted circular exponential amplification and a supramolecular structure ZnPPIX/G-quadruplex. First, a duplex DNA probe, which was constructed by the hybridization of a quadruplex-forming oligomer with a molecular beacon, was assembled on the magnetic nanoparticles (MNPs) as a reporter. A hairpin probe (HP)-containing sequence of GATC was used as the methylation substrate of DNA adenine methyltransferase (DAM). Once HP was methylated by DAM, it could be recognized and cleaved by Dpn I, which allows the release of a single-stranded DNA. The DNA (tDNA1) then hybridizes to the MNP probe, which then triggers the exonuclease III-mediated target exponential recycling reaction. Simultaneously, numerous quadruplex forming oligomers are liberated and folded into the G-quadruplex-ZnPPIX complexes with the help of zinc(ii)-protoporphyrin IX(ZnPPIX) on the MNP surface to give a remarkable fluorescence response. In the developed sensor, a small amount of target DAM can be converted to a large number of stable DNA triggers, leading to remarkable amplification of the target. Moreover, using MNPs as a vector of the sensor may reduce the interference from the real samples, which increases the anti-interference of the sensing system. Based on this unique amplification strategy, a very low detection limit down to 2.0 × 10−4 U mL−1 was obtained. Furthermore, the sensor could be used to evaluate the DAM activity in different growth stages of E. coli cells and screen Dam MTase inhibitors. Therefore, the strategy proposed here provides a promising platform for monitoring the activity and inhibition of DNA MTases and has great potential to be applied further in early clinical diagnostics and medical research. [ABSTRACT FROM AUTHOR]

A simple, label-free and sensitive fluorescence protein assay has been developed on the basis of aptamer exonuclease protection and exonuclease III (Exo III)-assisted recycling amplification-responsive cascade ZnPPIX/G-quadruplex supramolecular fluorescent labels. In the sensing system, a special aptamer probe containing the aptamer sequence at the 3′-terminus and the DNAzyme sequence at the 5′-terminus was applied, which has the capacity to recognize a protein target with high affinity and specificity. Exonuclease I (Exo I) can efficiently catalyze the degradation of free single stranded DNA probes in the 3′ to 5′ direction. In the presence of the target protein, the strong binding between the target protein and its aptamer can protect aptamer probes from degradation. Subsequently, the protected aptamer probes act as catalysators to trigger hybridization with the hairpin DNA probe that contains a partially “caged” G-quadruplex sequence. Upon interaction with the protected aptamer probes, the hairpin opens to yield the active G-quadruplex structure. In the presence of exonuclease III (Exo III), Exo III-assisted recycling amplification occurs generating numerous G-quadruplex supramolecular structures. The zinc(ii)-protoporphyrin IX (ZnPPIX) fluorophore binds to the G-quadruplexes and this results in the enhanced fluorescence of the fluorophore. The resulting fluorescence of the ZnPPIX/G-quadruplex provides the readout signal for the sensing event. Thrombin is used as the model analyte in the current proof-of-concept. The developed method was demonstrated to have very high sensitivity for the detection of proteins with a limit of detection of 0.2 pM without using washes or separations. In addition, this new method for protein detection is simple and inherits all the advantages of aptamers. The mechanism, moreover, may be generalized and used for other forms of protein analysis. [ABSTRACT FROM AUTHOR]

In this work, ZnO nano-needles were electrochemically deposited onto the surface of single carbon fiber. The influence of deposition condition on the surface morphology of ZnO nanostructures was investigated. A growth mechanism was suggested to elucidate the deposition process. Electrochemiluminescence conducted in 0.1 M KOH solution containing 0.1 M K2S2O8 and 0.1 M KCl displayed the stable and sensitive luminescent property of as-prepared ZnO nano-needles. The electrochemiluminescence intensity per projection area from ZnO nano-needles deposited on single carbon fiber was almost five orders of magnitude larger than that from ZnO nanostructures deposited on ITO and ZnO dip-coated on ITO. It demonstrated the high electrochemiluminescence efficiency of ZnO nano-needles deposited on single carbon fiber and the remarkable electrical conductivity of carbon fiber. This work presented a new strategy to deposit oxides on carbon fiber with tunable coverage and nanostructure. Furthermore, the excellent electrochemiluminescence property of ZnO nano-needles on carbon fiber highlights the importance and potential utility of such nanostructures in the development of optoelectronic and biomedical devices. [ABSTRACT FROM AUTHOR]

Novel three-dimensional Ag nanoflowers (3DAN) were successfully synthesized through a facile Cu2+ mediated solution method using N,N-dimethylformamide (DMF), which serves as both a reducing agent and a solvent at room temperature. It was found that the introduction of a trace amount of Cu2+ could greatly slow the rate of the Ag+ reaction and thus this process effectively reduced the growth speed of Ag nanoparticles allowing 3DAN to be formed. The mechanism underlying the self-assembly process and shape evolution of 3DAN were systematically investigated by varying reaction time. X-Ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the obtained products. X-Ray photoelectron spectroscopy (XPS) was used to assess the chemical state and surface composition of the 3DAN. UV-vis absorption spectra of the products collected from the reaction solution at various stages were taken to study their optical properties. In the measurement of surface-enhanced Raman scattering using rhodamine 6G (R6G) as the probe, the 3DAN exhibited a significant enhancement factor, indicating their potential applications in biosensing and nanodevices. [ABSTRACT FROM AUTHOR]