Presence Of EDC Research Articles

Synthesis of the Novel N-(2-Hexadecynoyl)-l-Homoserine Lactone and Evaluation of Its Antiquorum Sensing Activity in Chromobacterium violaceum.

Chromobacterium violaceum is commonly found in soil and freshwater within tropical and subtropical regions. Although not a common occurrence, this bacterium has the potential to cause severe diseases in humans and animals, such as liver and lung abscesses and septicemia. Herein we report the synthesis of novel N-acyl homoserine lactones (HSLs) to evaluate their effectiveness as antiquorum sensing (anti-QS) agents in C. violaceum. The HSLs were prepared through three synthetic approaches, where hexanoic acid, decanoic acid, 6-decynoic acid, or 2-hexadecynoic acid (2-HDA) was treated with commercially available l-homoserine lactone (HSL) hydrobromide in either dichloromethane or tetrahydrofuran in the presence of EDC and DMAP. The effectiveness of HSLs as anti-QS agents was assessed through susceptibility tests and violacein quantification. The most effective anti-QS inhibitor among all N-acyl-HSLs tested was the N-(2-hexadecynoyl)-l-homoserine lactone (HSL 4). Further experimental approaches, such as quantification of acyl-homoserine lactones and biofilm inhibitory tests, were carried out to determine the effect of HSL 4 on these QS-dependent mechanisms. These experiments showed that HSL 4 was highly effective at inhibiting the production of HSLs and biofilm in C. violaceum at 0.25, 0.50, and 1 mg/mL. In addition, the cytotoxicity activity was evaluated against Vero cells to determine the selectivity of HSL 4 as a nontraditional antibacterial agent. HSL 4 was not toxic against Vero cells at concentrations ranging from 0.0039 to 1 mg/mL. Molecular docking experiments were conducted to study the interactions between novel HSLs and CviR (PDB ID 3QP5), a receptor that plays a significant role in C. violaceum QS. In silico studies indicate that HSL 4 exhibits better interactions with Leu 72 and Gln 95 of the CviR binding pocket when compared to the other analogs. These results validate previous in vitro studies, such as susceptibility tests and violacein production assays. The findings above indicate that novel acetylenic HSLs may potentially be agents that combat bacterial communication and biofilm formation. However, further investigation is necessary to expand the spectrum of bacterial strains capable of resisting antibiotics through QS and evaluate the compounds' cytotoxicity in other cell lines.

Review on the electrochemical oxidation of endocrine-disrupting chemicals using BDD anodes

The application of synthetic diamond-based electrodes in water treatment has been shown to be promising, especially for boron-doped diamond (BDD). With a wide potential window and high overpotential for oxygen evolution among many more excellent qualities, BDD anodes surpass the capabilities of conventional electrodes. Currently, the synthesis and fabrication of low-cost BDD anodes are still in the primary stages of development. Electrochemical oxidation of EDCs on BDD anodes in water samples have been shown to be effective with very high removal efficiencies. The presence of this group of pollutants in wastewater effluents and various water matrices causes environmental concerns and requires an immediate solution due to their persistence and threat for both humas and wildlife. Extensive research on BDD continues to be carried out with various EDCs, such as parabens and pesticides, to determine the most suitable parameters, possible mechanisms of the degradation process, and its viability in large-scale applications. These efforts remain imperative as the presence of EDCs could severely affect human health and the surrounding environment. Although significant progress has been achieved, the advanced technology is unable to achieve feasible application in a large scale due to major hindrances. In this mini review, the focus was on the recent applications of electrochemical oxidation using BDD thin-film anodes (2019 to present) for the removal of a range of EDCs. The main factors that affect the performance of BDD anodes in the electrochemical oxidation of EDCs were discussed and evaluated, highlighting some ways to overcome the issues that prevent the technology from moving onto the next stage of development.

Hydrogel bioink based on clickable cellulose derivatives: Synthesis, characterization and in vitro assessment

Hydrogel is considered as a promising candidate for bioink in terms of biocompatibility, biodegradability, printability and supporting cellular behavior. Recently, carbohydrates derivatives containing alkyne and azide pendant functional groups have been used in medical applications due to their improved chemical, biological, functional properties, and their amenability for chemical reactions under mild conditions.In this work, a novel bioink was developed based on azide and alkyne of cellulose derivatives. Azido-hydroxyethyl cellulose (D.Sazido = 0.04) was synthesized via open-ring reaction of 1-azido-2,3-epoxypropane and characterized spectroscopically and titrimetrically. Alkyne derivative, propargyl carboxymethyl cellulose (D.Spropargyl = 1.72) was synthesized through coupling reaction with propargylamine in the presence of EDC and NHS. The click-gel scaffold was obtained by mixing the two novel candidates in the presence of copper (I) catalyst.Extrusion bio-plotting experiment was successfully conducted of the two solutions into coagulant Cu (I)/DMSO solutions and demonstrated the possibility of using the clickable cellulose derivatives as bioink precursors. Chemical and physical properties of the click-gel were demonstrated. The biocompatibility assay of the prepared click-gels showed high level of viability in the human skin fibroblast cells (HFB4) at concentration 100 μg/mL.

Fabrication of Nanoreactors Based on End-Functionalized Polymethacrylate and Their Catalysis Application

Polymer-based nanoreactor, which can be achieved by self-assembling of amphiphilic polymers in water, has attracted more and more attention in recent years. In this study, a kind of Pd-nanoreactor was fabricated by self-assembling of chiral palladium complex-containing amphiphilic polymers in water. Firstly, chain transfer reagent (CTA) CEPA-PyOx was obtained by condensation reaction of (S,S)-4-hydroxymethyl-5-phenyl-2-(2′-pyridinyl)-1,2-oxazoline (PyOx) and 4-cyano-4-[((ethylthio)carbonothioyl)thio] pentanoic acid (CEPA) in the presence of EDC·HCl. Next, polymethacrylate with a terminal chiral oxazoline ligand (CEPA-POEGMA36-PyOx) was synthesized through Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization. After removal of the thioester bond and coordination with palladium trifluoroacetate, the polymer self-assembled in water affording Pd-nanoreactor, which possess core-shell structure and with chiral palladium complex in the core. At last, the nanoreactor was successfully applied in the asymmetric catalytic synthesis of flavanone in aqueous phase, and the catalyst loading was greatly reduced compared to unsupported palladium complex. In the presence of low palladium loading (0.5 mol%), flavanone was successfully synthesized with excellent yield (98%) and high enantioselectivity (82%).

Induction of Superhydrophobicity in a Cellulose Substrate by LbL Assembly of Covalently Linked Dual-Sized Silica Nanoparticles Layers

Micro/nano texturized oxidized cellulose membranes (MNOCM) were constructed by layer-by-layer (LbL) assembly in which a base cellulose film was modified by covalent linkages to amino-functionalized silica nanoparticles (amino-SiO2 NPs, 260 nm diameter) and epoxy-functionalized silica nanoparticles (epoxy-SiO2 NPs, 30 nm diameter). The amino-SiO2 NPs grafted onto the MNOCM surface through a standard amidation reaction between the amino groups of the SiO2 NPs and the carboxyl groups of the MNOCM surface in the presence of EDC and NHS consequently forming a first layer of large (260 nm) nanoparticles; subsequently, it was reacted with smaller (30 nm) epoxy-SiO2 NPs. Continuous repetitions of these alternating sized silica NPs through a standard LbL approach lead to a highly micro/nano-texturized MNOCM film as shown by SEM, which was ultimately sealed with a layer of hydrophobic PFOTES (1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane). Although the wettability of MNOCM was no longer hydrophilic, it was found that at five layers deep of NPs, it became superhydrophobic as evidenced by a water contact angle of 151° ± 2° and slide angle of 4°. The change in wettability was attributed to increases in final LbL layer surface roughness induced by the sufficient LbL layering of alternating sizes of NPs akin to what is observed in a lotus leaf surface. It was also noted that these superhydrophobic-MNOCM materials displayed good self-cleaning.

Design, synthesis, and antimicrobial activity of novel 5-substituted indole-2-carboxamide derivatives

A series of novel, bioactive 5-substituted indole-2-carboxamide derivatives (10a–t and 14a–k) are synthesized by the coupling of 5-substituted indole-2-carboxylic acids with various amines in the presence of EDC HCl/HOBt in DMF/CH2Cl2 as a solvent. In vitro, antibacterial activity of titled compounds against pathogenic bacteria Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and antifungal activity against pathogenic fungi Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, and Candida parapsilosis are evaluated using gentamicin/ciprofloxacin and fluconazole/oxiconazole as standard drugs, respectively. The majority of the synthesized compounds exhibited good antibacterial activity, but surprisingly none showed antifungal activity. Compounds 10c, 10d, 10i, 10j, 10l–n, 14g, 14h, 14i, 14j, and 14k exhibited high inhibitory antibacterial activity with MIC values in the range of 0.12–6.25 µg/mL. Interestingly, compounds 14i, 14j, and 14k exhibited excellent antibacterial activity against K. pneumoniae and E. coli compare to synthesized compound. All the experimental results promote us to consider this series as a starting point for the development of novel and more potent antibacterial agents in the future.

Synthesis, Spectral Characterization and Antioxidant Activity of Novel Zafirlukast Sulfonyl Derivatives

AbstractA new series of cyclopentyl 3‐(2‐methoxy‐4‐(piperazine‐1‐carbonyl)benzyl)‐1‐methyl‐1H‐indol‐5‐ylcarbamate sulfonyl derivatives were synthesized by the reaclion of 4‐((5‐(cyclopentyloxycarbonylamino)‐1‐methyl‐1H‐indol‐3‐yl)methyl)‐3‐methoxybenzoic acid (ZAK drug intermediate) with Boc piperazine in the presence of EDC⋅HCl, HOBt, TEA in DMF followed by deboxylation by using 2N HCl or 35 % HCl in acetone to get an intermediate compound. Further, this compound was treated with various substituted benzene sulfonyl chlorides in the presence of TEA in THF to afford title compounds. All the title compounds were characterized by 1HNMR, 13CNMR, IR and mass spectral data. The title compounds and starting material were evaluated for their antioxidant activity by using the DPPH, H2O2 and NO methods. The results revealed that some of the compounds have shown significant antioxidant activity.

Rationally modified estrogen receptor protein as a bio-recognition element for the detection of EDC pollutants: strategies and opportunities.

The estrogen receptor protein (ER) can bind a vast number of organic pollutants widely spread in the environment and collectively known as Endocrine Disrupting Chemicals, EDCs. Its broad selectivity makes it an ideal bio-recognition element for the detection of EDCs. Here we describe the strategy and rationale for the design of ER based biosensors and assays that generate a signal in the presence of EDCs. The opportunity to use either natural or rationally modified ER molecules is discussed. The latter approach was successfully applied in the EU-FP7 project RADAR, with the aim to develop a novel biosensor for the detection of organic pollutants both in the environment and in commercial water products.

Synthesis and cytotoxic activity of 3, 4, 11-trihydroxyl modified derivatives of bergenin

To synthesize a series of 3-, 4-, and/or 11-trihydroxy modified bergenin derivatives and evaluated their cytotoxic activity in vitro. The phenolic hydroxyl groups of bergenin were protected by benzyl groups with benzyl bromide. Treatment of dibenzyl bergenin with the corresponding acid in the presence of EDC·HCl and DMAP in CH2Cl2, followed by hydrogenation over Pd/C catalysts, afforded derivatives of bergenin esters. All of the target compounds were identified by IR, MS, and 1H NMR. Twenty-six novel and three known derivatives of bergenin esters were synthesized. Their cytotoxicity values were evaluated by the MTT assay on the inhibition of DU-145 and BGC-823 cells in vitro. Several triply-substituted (3a, 4a, 5a, 6a, 7a) and doubly-substituted (8b, 9b) bergenin derivatives exhibited higher cytotoxic activity than bergenin. The result showed that the size of substituents and the lipophilicity of the bergenin esters displayed an important role on their cytotoxic activity.

Quantification of particle-conjugated or particle-encapsulated peptides on interfering reagent backgrounds.

Particle-based technologies are increasingly being used in diagnostics and therapeutics. The particles employed in these applications are usually composed of polymers such as poly(lactide-co-glycolide) (PLG) and functionalized with peptides or proteins. Peptide or protein conjugation to particles is frequently achieved using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), while dimethyl sulfoxide (DMSO) is used to retrieve surface-attached or encapsulated peptides or proteins by solubilizing the particles. We examined strategies based on bicinchoninic acid (BSA), Coomassie Plus, and 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA) assays for the quantification of surface-attached or encapsulated peptides or proteins. We determined that the CBQCA assay is a highly sensitive and accurate substitute for radioactivity-based assays that is suitable for measuring multiple particle-bound or particle-encapsulated peptides or proteins in the presence of EDC or PLG in DMSO, compounds that interfere with the more commonly used BSA and Coomassie Plus assays. Our strategy enables the accurate quantification of peptides or proteins loaded onto or into particles-an essential component of particle-based platform design for diagnostics and therapeutics.

BSA–boronic acid conjugate as lectin mimetics

We report bovine serum albumin (BSA)–boronic acid (BA) conjugates as lectin mimetics and their glyco-capturing capacity. The BSA–BA conjugates were synthesized by amidation of carboxylic acid groups in BSA with aminophenyl boronic acid in the presence of EDC, and were characterized by Alizarin Red S (ARS) assay and SDS–PAGE gel. The BSA–BA conjugates were immobilized onto maleimide-functionalized silica beads and their sugar capturing capacity and specificity were confirmed by ARS displacement assay. Further, surface plasmon resonance (SPR) analysis of the glyco-capturing activity of the BSA–BA conjugates was conducted by immobilizing BSA–BA onto SPR gold chip. Overall, we demonstrated a BSA–BA-based lectin mimetics for glyco-capturing applications. These lectin mimetics are expected to provide an important tool for glycomics and biosensor research and applications.

Polyinosinic:polycytidylic acid loading onto different generations of PAMAM dendrimer-coated magnetic nanoparticles

Poly (I:C), which is a synthetic double-stranded RNA, have significant toxicity on tumor cells. The immobilization of Poly (I:C) onto nanoparticles is important for the fabrication of targeted delivery systems. In this study, different generations of newly synthesized PAMAM dendron-coated magnetic nanoparticles (DcMNP) which can be targeted to the tumor site under magnetic field were efficiently loaded for the first time with Poly (I:C). Different generations of DcMNPs (G2, G3, G4, G5, G6, and G7) were synthesized. Poly (I:C) activation was achieved in the presence of EDC and 1-methylimidazole. Loading of Poly (I:C) onto DcMNPs was followed by agarose gel electrophoresis. Acidic reaction conditions were found as superior to basic and neutral for binding of Poly (I:C). In addition, having more functional groups at the surface, higher generations (G7, G6, and G5) of PAMAM DcMNPs were found more suitable as a delivery system for Poly (I:C). Further in vitro and in vivo analyses of Poly (I:C)/PAMAM magnetic nanoparticles may provide new opportunities for the selective targeting and killing of tumor cells.

ASSESSMENT OF IMMUNOGENICITY OF CP8, CLFA-FnBPB AND CP8-CLFA-FnBPB ANTIGENS

To assess the effects of conjugating Capsular Polysaccharide (CP) with Clumping factor A (ClfA) and Fibronectin-Binding Proteins B (FnBPB) on the immunogenicity of the antigen, CP was isolated and purified from serotype 8 (CP8) Staphylococcus aureus from bovine mastitis dairy herds in Inner Mongolia and ClfA-FnBPB was produced with Escherichia coli encoding a fusion protein ClfA-FnBPB gene. The CP8-ClfA-FnBPB complete antigen was constructed by first attaching Alcohol Dehydrogenase (ADH) to CP8 which was then combined with ClfA-FnBPB at the presence of EDC (1-ethyl-3, (3-di-methylaminopropyl carbodiimide). The immunogenicity of CP8, ClfA-FnBPB and CP8- ClfA-FnBPB was determined by intraperitoneal injecting 40 8-wk old of Balb/c mice four groups with 0.2 mL/mouse of 0.9% NaCl (Control) or CP8, ClfA-FnBPB and CP8-ClfA-FnBPB solution. The mice were group-fed with same pellet diet in an environmentally controlled room with a constant temperature of 22°C and 12h/24h light. The concentration of CP8, ClfA-FnBPB or CP-ClfA-FnBPB in respective solutions was 50, 25 or 75 µg mL-1. Two injections were given, on d7 and d21 of the experiment. Blood samples were taken on d0, d14, d21 and d28 and measured for the antibodies titer. On d28, all mice were injected with CP8 type of S. aureus and the mortality of the mice determined for the following 14 days (challenge test). The results showed that ClfA-FnBPB was successfully expressed by E coli and the isolated and purified ClfA-FnBPB was successfully conjugated with CP8 to yield a CP8-ClfA-FnBPB complete antigen. Mice immunized with CP8-ClfA-FnBPB had higher antibody titer than that of CP8 (p

Endocrine-disrupting chemicals in human follicular fluid impair in vitro oocyte developmental competence

Increased global industrial activity has exposed humans to a wide variety of chemical substances some of which, called 'endocrine-disrupting chemicals' (EDCs) or 'endocrine disruptors', can disrupt the endocrine system in the body. The ovarian follicle is a very fragile micro-environment where interactions between hormones, growth factors, the oocyte and its surrounding somatic cells are essential to generate a fully competent oocyte. In vitro experiments suggest that EDCs can disturb this finely tuned balance, but very scarse in vivo data are available to confirm this assumption. Therefore, we have investigated if the presence of EDCs in human follicular fluid is a risk factor for the developmental competence of an in vivo exposed oocyte. Furthermore, because of the limited access to human follicular fluid, we verified if follicular fluid contamination can be predicted based on EDC levels in serum. Follicular fluid (n = 40) and serum (n = 20) samples from women undergoing assisted reproductive technology (ART) were analyzed by means of gas chromatography combined with mass spectrometry to examine the presence of different EDCs, such as polychlorinated biphenyls, polybrominated diphenyl ethers and organochlorine pesticides. Statistical models were used to investigate the relation between the characteristics and ART results of the patients and the contamination status of their follicular fluid and to assess the capacity of serum samples to predict follicular fluid contamination. Chlorinated biphenyl 153 (72 ± 44 and 201 ± 106 pg/ml) and p,p'-DDE (392 ± 348 and 622 ± 406 pg/ml) were the compounds found in the highest concentrations in follicular fluid and serum samples, respectively. A new variable principal component 1, representing the overall contamination status of the follicular fluid samples, is strongly associated with fertilization rate (P < 0.00001) and the proportion of high-quality embryos relative to the amount of retrieved oocytes (P < 0.05), even when the analysis is adjusted for age, estradiol concentration, BMI, fertilization procedure and male subfertility as explanatory variables. The strong correlations between the EDC concentrations in serum and follicular fluid (r ≥ 0.93) allowed us to build regression models, which accurately predict EDC concentrations in the follicular fluid based on serum samples. An overall higher EDC contamination in the follicular micro-environment was associated with a decreased fertilization rate and consequently with a lower chance of an oocyte to develop into a high-quality embryo. In addition, EDC concentrations in serum were reliable predictors of the contamination status of the follicular micro-environment.

Synthesis and Biological Screening of Thiazole-5-Carboxamide Derivatives

Thiazole derivatives have been studied extensively because of their ready accessibility, diverse chemical activity. The chemistry of thiazole continues to draw the attention of synthetic organic chemists due to their varied biological activities, 1-5 such as antibacterial, antitubercular, anti-cancer, antifungal and anti-inflammatory activities. 6-9 Also 4-(4-aminophenyl)-thiazoles have been reported to exhibit antitubercular activity. 10 5-azole carboxamide derivatives show antianoxic activity. 11 The aryl imidazolyl carboxamide derivatives were shown to be cannabinoid CB1 receptor antagonist. 12,13 Based on these observations, substituted thiazole carboxamides were synthesized and subjected to microbial screening. Here in, we report a simple efficient and effective protocol for the synthesis of N-(4-(2-benzylthiazol-4-yl)phenyl)-2-benzyl-4-methylthiazole-5-carboxamide derivatives using EDC-HOBt coupling in DMF and their antimicrobial activities. The target compounds 5a-n were synthesized by reaction of 2-benzyl-4-methylthiazole-5-carboxylic acid 3a-c with 2-methyl/substitutedbenzyl-4-(4-aminophenyl) thiazoles 2a-f in the presence of EDC- HOBt in DMF in good yields (Scheme 1). The yields, melting points and molecular formula of carboxamide derivatives 5a-n are listed in Table 1. The reaction failed when ethyl 2-benzyl4-methylthiazole-5-carboxylate 1a-c was refluxed with 2methyl/substitutedbenzyl-4-(4-aminophenyl) thiazole 2af in absolute ethanol for 24 h. When the same reaction was carried out with acid chloride or mixed anhydride activation of the carboxylic acid, the yields were poor. The amino phenyl thiazole derivatives 2a-f were synthesized using literature protocol. 10,14 The target compounds were characterized by IR, 1 H NMR, 13 C NMR, mass and elemental analysis and all the spectral data are in accordance with the assumed structures. In additions to the signals for aromatic protons 1 H NMR spectra of the compounds 5a-n reveal singlet at 2.73-2.78 ppm for thiazole-CH3 protons. Furthermore, the spectra show singlet for methylene protons of benzylic carbon atoms in the range 3.73- 4.41 ppm. These compounds were found to be effective against the Gram-positive bacteria S. aureu and B. Subtilis and Gramnegative bacteria E. coli and P. aeruginosa. The zones of inhibition in mm, for the bioactive compounds against microorganisms tested are reported in Table 2. N-(4-(2-(4chlorobenzylthiazol-4-yl)phenyl)-2-(4-chlorobenzyl)-4methylthiazole-5-carboxamide (5k) is active against both gram positive and gram negative stains but looses activity on adding one chlorine at 3-position as in N-(4-(2-(3,4dichlorobenzylthiazol-4-yl)phenyl)-2-(4-chlorobenzyl)4-methylthiazole-5-carboxamide (5l). When chlorine in the first benzyl ring in 5l, was replaced by fluorine as in N(4-(2-(3,4-dichlorobenzylthiazol-4-yl)phenyl)-2-(4-fluorobenzyl)-4-methylthiazole-5-carboxamide (5i), it showed antibacterial activity. N-(4-(2-(4-fluorobenzylthiazol-4-yl)phenyl)-2-(4-chlorobenzyl)-4-methylthiazole-5-carboxamide (5m) showed antifungal activity, but when one chlorine atom is added at 2-position as in N-(4-(2-(4-fluorobenzyl)thiazol-4-yl)phenyl)-2-(2,4-dichlorobenzyl)-4-methylthiazole-5-carboxamide (5c), it showed antibacterial activity with loss of antifungal activity. 2-methyl substituted carboxamide derivatives (5a, 5f) showed only antibacterial activity. The dimethoxy derivative 5n was found to be inactive against all stains.

N-acryloxysuccinimide: Synthesis, characterization, and incorporation in dental adhesives

In an attempt to enrich the world of dentistry through the development of new materials, this study proposes to synthesize and incorporate a monomer containing the N-hydroxysuccinimide (NHS) ester reactive group to a dental adhesive. As such, this study developed a simple method to obtain NHS esters by employing acrylic acid (AA) and NHS in the presence of EDC ( N-ethyl- N′-(3-dimethylaminopropyl)carbodiimide), from an aprotic medium. The experimental N-acryloxysuccinimide (NSA) monomer was analyzed by infrared spectroscopy (FTIR) and nuclear magnetic resonance of hydrogen ( 1H NMR). This monomer was then incorporated within a prepared dental adhesive, in a 5% proportion. The modified adhesive, containing NSA, was applied to the dental surface of bovine teeth to obtain an adhesive/dentin interface in vitro. The characterization of this interface by Raman spectroscopy presented the formation of new amide bonds. Moreover, through scanning electron microscopy (SEM), it became possible to observe an intense penetration of this modified adhesive on the dental surface. Considering the outcome, it can be concluded that the synthesized NSA monomer provided a favorable condition for the dental adhesives to interact chemically with the dentin collagen fibers.

Covalent Heparin Modification of a Polysulfone Flat Sheet Membrane for Selective Removal of Low‐Density Lipoproteins: A Simple and Versatile Method

A simple, convenient and economical method for the heparinization of PSf membranes is described, with the aim of preparing an LDL adsorber for simultaneous LDL apheresis and hemodialysis. An atmospheric pressure glow discharge generator is used to activate the PSf membrane surface, with subsequent chemical binding of heparin in the presence of EDC and NHS. ATR-FTIR spectroscopy and XPS measurements confirm successful surface modification. The PSf-Hep membrane shows good blood compatibility, with a relatively low amount and normal morphology of adherent platelets. ELISA results indicate that the PSf-Hep membrane exhibits excellent selective affinity for LDL in single and binary protein solutions, suggesting potential applications in hemodialysis with simultaneous LDL removal.

ChemInform Abstract: Using Benzotriazole Esters as a Strategy in the Esterification of Tertiary Alcohols.

AbstractBenzotriazole esters, formed in situ from carboxylic acids and HOBt in the presence of EDC, are efficient intermediates in the esterification with tert‐butyl alcohol using either DMAP or calcinated hydrotalcite as the base.

Stereocontrolled Photodimerization with Congested 1,8-Bis(4′-anilino)naphthalene Templates

Suzuki cross-coupling of a 1,8-dihalonaphthalene with 4-methoxy-3-methylphenylboronic acid or 4-acetamidophenylboronic acid and subsequent functional group transformation gave 1,8-bis(3'-methyl-4'-anilino)naphthalene, 16, and 1,8-bis(4'-anilino)naphthalene, 21, in 65% and 90% overall yield, respectively. These congested compounds exhibit two cofacial aniline rings that favor a proximate, parallel arrangement of covalently attached cinnamoyl units suitable for stereoselective photodimerization. The [2 + 2]cycloaddition was found to proceed with high yield and exclusive formation of cis,trans,cis-cyclobutane-1,2-dicarboxylic acids. Amide formation with cinnamoyl chloride and template 21 followed by photochemical dimerization and acidic hydrolysis gave β-truxinic acid, 10, in 69% overall yield. Coupling of 21 and (E)-3-(3,4-dimethylphenyl)acrylic acid in the presence of EDC, UV irradiation, and cleavage gave cis,trans,cis-3,4-bis(3,4-dimethylphenyl)cyclobutane-1,2-dicarboxylic acid, 26, in 60% yield. In both cases, the template was quantitatively recovered.

Detection of Bifidobacterium Species-specific 16S rDNA Based on QD FRET Bioprobe

Fluorescence resonance energy transfer (FRET) that consists of quantum dot as donors and organic fluorophore dyes as acceptors has been a very important method to detect biomolecules such as nucleic acids. In this work, we established a new FRET detection system of Bifidobacterium species-specific 16S rDNA using QD-ROX FRET bioprobe, in which 525 nm QD-DNA conjugation consisted of the carboxyl-modified QD and the amino-modified DNA in the presence of EDC. Both ROX-DNA and the conjugation above could hybridize with the target DNA after forming the QD-ROX bioprobe. When the hybridization made the distance between the QD and ROX to meet FRET effect needed, 525 nm QD fluorescence intensity decreased and ROX fluorescence intensity increased. In the control, there was no notable change of fluorescence intensities without target DNA. It is very clear that the change of the QD and ROX fluorescence intensities provide the good base and guaranty for this rapid and simple detection system.