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Jing Liu, Dujuan Zhao, Wenxiu He, Huiyuan Zhang, Zhonghao Li, Yuxia Luan
The anti-leukemia effect of cytarabine (Ara-C) is severely restricted by its high hydrophilic properties and rapid plasma degradation. Herein, a novel amphiphilic small molecular prodrug of Ara-C was developed by coupling a short aliphatic chain, hexanoic acid (HA) to 4-NH2 of the parent drug. Based on the amphiphilic nature, the resulting bioconjugate (HA-Ara) could spontaneously self-assemble into stable spherical nanoassemblies (NAs) with an extremely high drug loading (∼71wt%). Moreover, folate receptor (FR)-targeting NAs with high grafting efficient folic acid - bovine serum albumin (FA-BSA) conjugate immobilized on the surface (NAs/FA-BSA) was prepared...
October 19, 2016: Journal of Colloid and Interface Science
Oliver R Baudendistel, Daniel E Wieland, Magnus S Schmidt, Valentin Wittmann
Ligation reactions at the anomeric center of carbohydrates have gained increasing importance in the field of glycobiology. Oxyamines are frequently used in labeling, immobilization, and bioconjugation of reducing carbohydrates. Herein, we present a systematic investigation of these ligation reactions under aqueous conditions. A series of four unprotected monosaccharides (glucose, N-acetylglucosamine, mannose, and 2-deoxyglucose) and one disaccharide (N,N'-diacetylchitobiose) was reacted with three primary and one secondary oxyamine...
October 24, 2016: Chemistry: a European Journal
Maria Luisa Navacchia, Aurore Fraix, Nicola Chinaglia, Eleonora Gallerani, Daniela Perrone, Venera Cardile, Adriana C E Graziano, Massimo L Capobianco, Salvatore Sortino
This contribution reports the synthesis of some novel bioconjugates with anticancer activity and able to release nitric oxide (NO) under visible light excitation. The 4-nitro-2-(trifluoromethyl)aniline derivative, a suitable NO photodonor, was conjugated with 2'-deoxyadenosine and urso- and cheno-deoxycholic acid derivatives, through a thioalkylic chain or the 4-alkyl-1,2,3-triazole moiety. Photochemical experiments demonstrated the effective release of NO from 2'-deoxyadenosine and ursodeoxycholic acid conjugates under the exclusive control of visible light inputs...
October 13, 2016: ACS Medicinal Chemistry Letters
Yuanyuan Wu, Vincent T Remcho
Capillary electrophoresis (CE) coupled with UV absorbance detection has been applied as an analysis tool for carbon dots (C-dots), which were hydrothermally synthesized from precursors citric acid (CA) and ethylene diamine (EDA). An alkaline working buffer (100mM tris acetate, pH 8.4) was found to be optimal for rapid and reliable analysis of C-dots. A calibration curve was established over a broad concentration range (0.5-10mg/mL) with excellent linearity (R(2)=0.9989). The CE method was also applied to enhance understanding of and facilitate optimization of ensuing C-dot biolabeling reactions...
December 1, 2016: Talanta
Eduardo Rodrigo, Inés Alonso, José Luis García Ruano, M Belén Cid
The easily available vinyl sulfone 3 showed a great potential for new applications in several fields, such as organic synthesis and bioconjugates formation. This was demonstrated by performing a systematic assessment of its reactivity in Michael, radical and cycloaddition reactions. Heteroaryl vinyl sulfone 3 presented an excellent output in terms of reactivity and selectivity, proving superior to phenyl vinyl sulfone 1 and with clear advantages over bis-sulfone 2. This behavior might be due to the conformational and orbital control exerted by the tetrazole unit according to DFT calculations...
October 21, 2016: Journal of Organic Chemistry
Abbas Shahsavari, Mehdi Azad, Naser Mobarra, Koorosh Goodarzvand Chegini, Nematollah Gheibi
Calprotectin is member of the S-100 protein family with a wide plethora of intra-and extracellular functions. Anticancer activities, antimicrobial effects and being a qualified disease marker are among the compelling features of this protein to be used as a pharmaceutical agent. However, there are several impediments to applications of protein pharmaceuticals including: proteolytic degradation, short circulating half-life, low solubility and immunogenicity. Pegylation is a common bioconjugation polymer capable of overcoming these drawbacks...
October 18, 2016: Protein Journal
Gary A Clawson, Thomas Abraham, Weihua Pan, Xiaomeng Tang, Samuel S Linton, Christopher O McGovern, Welley S Loc, Jill P Smith, Peter J Butler, Mark Kester, James H Adair, Gail L Matters
Pancreatic ductal adenocarcinomas (PDACs) constitutively express the G-protein-coupled cholecystokinin B receptor (CCKBR). In this study, we identified DNA aptamers (APs) that bind to the CCKBR and describe their characterization and targeting efficacy. Using dual SELEX selection against "exposed" CCKBR peptides and CCKBR-expressing PDAC cells, a pool of DNA APs was identified. Further downselection was based on predicted structures and properties, and we selected eight APs for initial characterizations. The APs bound specifically to the CCKBR, and we showed not only that they did not stimulate proliferation of PDAC cell lines but rather inhibited their proliferation...
October 18, 2016: Nucleic Acid Therapeutics
Boriphat Methachan, Kamolrat Thanapprapasr
The emergence of theranostics with ultrasound technology is a promising development, as it opens pathways to providing more effective treatments for cancer. Advancements in ultrasound imaging would give a more detailed and accurate image for better diagnosis and treatment planning. Polymeric ultrasound contrast agents (UCAs) are appealing because they are stable and easily modified for active targeting. In addition, a better therapy could be achieved in conjunction with advancements in UCAs. The active targeting not only makes the precise imaging possible, but also leads to targeted delivery of active components to specific local treatment sites...
October 14, 2016: Ultrasound in Medicine & Biology
Tjerk J Sminia, Han Zuilhof, Tom Wennekes
This review discusses the advances in metabolic oligosaccharide engineering (MOE) from 2010 to 2016 with a focus on the structure, preparation, and reactivity of its chemical probes. A brief historical overview of MOE is followed by a comprehensive overview of the chemical probes currently available in the MOE molecular toolbox and the bioconjugation techniques they enable. The final part of the review focusses on the synthesis of a selection of probes and finishes with an outlook on recent and potential upcoming advances in the field of MOE...
September 16, 2016: Carbohydrate Research
Sudath Hapuarachchige, Dmitri Artemov
Click chemistry provides fast, convenient, versatile, and reliable chemical reactions that take place between pairs of functional groups of small molecules that can be purified without chromatographic methods. Due to the fast kinetics and low or no elimination of byproducts, click chemistry is a promising approach that is rapidly gaining acceptance in drug discovery, radiochemistry, bioconjugation, and nanoscience applications. Increasing use of click chemistry in synthetic procedures or as a bioconjugation technique in diagnostic imaging is occurring because click reactions are fast, provide a quantitative yield, and produce a minimal amount of nontoxic byproducts...
October 2016: Topics in Magnetic Resonance Imaging: TMRI
Katarzyna Szot-Karpińska, Piotr Golec, Adam Lesniewski, Barbara Palys, Frank Marken, Joanna Niedziółka-Jönsson, Grzegorz Wegrzyn, Marcin Łoś
With the advent of nanotechnology, carbon nanomaterials such as carbon nanofibers (CNF) have aroused substantial interest in various research fields including energy storage and sensing. Further improvement of their properties might be achieved via application of viral particles such as bacteriophages. In this report we present a filamentous M13 bacteriophage, with a point mutation in gene VII (pVII-mutant-M13), that selectively binds to the carbon nanofibers to form 3D structures. The phage-display technique was utilized for the selection of the pVII-mutant-M13 phage from the phage display peptide library...
October 17, 2016: Bioconjugate Chemistry
D Madea, T Slanina, P Klán
A bioorthogonal 'catch and photorelease' strategy, which combines alkyne-azide cycloaddition between p-hydroxyphenacyl azide and alkyne derivatives to form a 1,2,3-triazole adduct and subsequent photochemical release of the triazole moiety via a photo-Favorskii rearrangement, is introduced. The first step can also involve photorelease of a strained alkyne and its Cu-free click reaction with azide.
October 14, 2016: Chemical Communications: Chem Comm
Giuseppe Meola, Henrik Braband, Paul Schmutz, Michael Benz, Bernhard Spingler, Roger Alberto
The synthesis of mono- and difunctionalized [Re(η(6)-C6H5R)(η(6)-C6H6-nRn)](+) (n = 0, 1; R = COOH, Br) complexes starting from [Re(η(6)-benzene)2](+) is described. The lithiation of [Re(η(6)-benzene)2](+) with n-BuLi leads preferentially to the neutral, alkylated product [Re(η(6)-C6H6)(η(5)-C6H6-Bu)] but not to the expected deprotonation of the arene ring. Deprotonation/lithiation with LDA gave the mono- and the dilithiated products in situ. Their reactions with 1,1,2,2-tetra-bromoethane (TBE) or with CO2, respectively, gave [Re(η(6)-C6H5Br)(η(6)-C6H6)](+), [Re(η(6)-C6H5Br)2](+), or [Re(η(6)-C6H5COOH)(η(6)-C6H6)](+), [Re(η(6)-C6H5COOH)2](+)...
October 12, 2016: Inorganic Chemistry
Kenward King Ho Vong, Satoshi Maeda, Katsunori Tanaka
Alkyl esters, such as propargyl esters, typically lack the electron-withdrawing inductive effects needed to participate in nucleophilic acyl substitution reactions. Herein, we report an unusual observation where glycine propargyl ester derivatives displayed selective, base-independent reactivity towards linear alkylamines under mild, metal-free conditions. Through global reaction route mapping (GRRM) modeling calculations, it is predicted that these observations may be governed by factors related to hydrogen bonding and intermolecular interactions, rather than electron-withdrawing inductive effects...
October 12, 2016: Chemistry: a European Journal
Yuliia Vyborna, Mykhailo Vybornyi, Robert Häner
The pathway diversity of the self-assembly of amphiphilic DNA-pyrene conjugates is described. The hydrophobic pyrene units drive the self-assembly of the anionic oligomers in an aqueous environment into ribbon-shaped, DNA-grafted supramolecular polymers. Isothermal mixing of two types of sorted ribbons, each of which contains only one kind of two complementary oligonucleotides, results in the formation of tight networks. Thermal disassembly of these kinetically trapped networks and subsequent re-assembly of the liberated components leads to mixed supramolecular polymers, which now contain both types of oligonucleotides...
October 12, 2016: Bioconjugate Chemistry
Peng Dai, Chi Zhang, Matthew Welborn, James J Shepherd, Tianyu Zhu, Troy Van Voorhis, Bradley L Pentelute
Highly efficient and selective chemical reactions are desired. For small molecule chemistry, the reaction rate can be varied by changing the concentration, temperature, and solvent used. In contrast for large biomolecules, the reaction rate is difficult to modify by adjusting these variables because stringent biocompatible reaction conditions are required. Here we show that adding salts can change the rate constant over 4 orders of magnitude for an arylation bioconjugation reaction between a cysteine residue within a four-residue sequence (π-clamp) and a perfluoroaryl electrophile...
September 28, 2016: ACS Central Science
Yuan Cao, Giang K T Nguyen, Samuel Chuah, James P Tam, Chuan-Fa Liu
Herein we report a novel enzymatic bioconjugation method to prepare peptide dendrimers. Under the catalysis of a newly discovered peptide ligase, butelase 1, peptide dendrimers of di-, tetra- and octabranches were successfully synthesized using thiodepsipeptides as acyl donors for ligation with lysyl dendrimeric scaffolds. The efficient assembly of the highly clustered dendrimeric structure highlighted the versatility of butelase 1. We also showed that our synthetic antibacterial peptide dendrimers containing an RLYR motif are highly potent and broadly active against antibiotic-resistant strains...
October 10, 2016: Bioconjugate Chemistry
M H Staegemann, S Gräfe, R Haag, A Wiehe
The reaction of amines with pentafluorophenyl-substituted A3B-porphyrins has been used to obtain different useful reactive groups for further functionalization and/or conjugation of these porphyrins to other substrates or materials. Porphyrins with alkenyl, alkynyl, amino, azido, epoxide, hydroxyl, and maleimido groups have thus been synthesized. For the first time such functionalized porphyrins have been conjugated to hyperbranched polyglycerol (hPG) as a biocompatible carrier system for photodynamic therapy (PDT) using the copper(i)-catalyzed 1,3-dipolar cycloaddition (CuAAC)...
September 26, 2016: Organic & Biomolecular Chemistry
Ankit Dhaundiyal, Sunil K Jena, Sanjaya K Samal, Bhavin Sonvane, Mahesh Chand, Abhay T Sangamwar
OBJECTIVES: This study was designed to demonstrate the potential of novel α-lipoic acid-stearylamine (ALA-SA) conjugate-based solid lipid nanoparticles in modulating the pharmacokinetics and hepatotoxicity of tamoxifen (TMX). METHODS: α-lipoic acid-stearylamine bioconjugate was synthesized via carbodiimide chemistry and used as a lipid moiety for the generation of TMX-loaded solid lipid nanoparticles (TMX-SLNs). TMX-SLNs were prepared by solvent emulsification-diffusion method and optimized for maximum drug loading using rotatable central composite design...
October 5, 2016: Journal of Pharmacy and Pharmacology
Wilbur H Chen, Karen L Kotloff
Shigella sp. represent the second most common etiologic pathogen causing childhood diarrhea in developing countries. There are no licensed Shigella vaccines and their progress has been limited. In this issue of Clinical and Vaccine Immunology, Riddle and colleagues report results from a phase 1 study of a parenterally administered monovalent O-polysaccharide "bioconjugate" directed against S. flexneri 2a. Ultimately the goal is to develop a broad-spectrum Shigella vaccine to address this public health concern...
October 5, 2016: Clinical and Vaccine Immunology: CVI
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